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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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16 pages, 2713 KiB  
Review
Machine Learning-Driven Innovations in Microfluidics
by Jinseok Park, Yang Woo Kim and Hee-Jae Jeon
Biosensors 2024, 14(12), 613; https://doi.org/10.3390/bios14120613 - 13 Dec 2024
Cited by 9 | Viewed by 3445
Abstract
Microfluidic devices have revolutionized biosensing by enabling precise manipulation of minute fluid volumes across diverse applications. This review investigates the incorporation of machine learning (ML) into the design, fabrication, and application of microfluidic biosensors, emphasizing how ML algorithms enhance performance by improving design [...] Read more.
Microfluidic devices have revolutionized biosensing by enabling precise manipulation of minute fluid volumes across diverse applications. This review investigates the incorporation of machine learning (ML) into the design, fabrication, and application of microfluidic biosensors, emphasizing how ML algorithms enhance performance by improving design accuracy, operational efficiency, and the management of complex diagnostic datasets. Integrating microfluidics with ML has fostered intelligent systems capable of automating experimental workflows, enabling real-time data analysis, and supporting informed decision-making. Recent advances in health diagnostics, environmental monitoring, and synthetic biology driven by ML are critically examined. This review highlights the transformative potential of ML-enhanced microfluidic systems, offering insights into the future trajectory of this rapidly evolving field. Full article
(This article belongs to the Special Issue Design, Fabrication, and Applications of Microfluidic Devices for Biosensing)
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13 pages, 3048 KiB  
Article
Paper-Based DNA Biosensor for Rapid and Selective Detection of miR-21
by Alexander Hunt, Sri Ramulu Torati and Gymama Slaughter
Biosensors 2024, 14(10), 485; https://doi.org/10.3390/bios14100485 - 8 Oct 2024
Cited by 5 | Viewed by 2604
Abstract
Cancer is the second leading cause of death globally, with 9.7 million fatalities in 2022. While routine screenings are vital for early detection, healthcare disparities persist, highlighting the need for equitable solutions. Recent advancements in cancer biomarker identification, particularly microRNAs (miRs), have improved [...] Read more.
Cancer is the second leading cause of death globally, with 9.7 million fatalities in 2022. While routine screenings are vital for early detection, healthcare disparities persist, highlighting the need for equitable solutions. Recent advancements in cancer biomarker identification, particularly microRNAs (miRs), have improved early detection. MiR-21 is notably overexpressed in various cancers and can be a valuable diagnostic tool. Traditional detection methods, though accurate, are costly and complex, limiting their use in resource-limited settings. Paper-based electrochemical biosensors offer a promising alternative, providing cost-effective, sensitive, and rapid diagnostics suitable for point-of-care use. This study introduces an innovative electrochemical paper-based biosensor that leverages gold inkjet printing for the quantitative detection of miR-21. The biosensor, aimed at developing cost-effective point-of-care devices for low-resource settings, uses thiolated self-assembled monolayers to immobilize single-stranded DNA-21 (ssDNA-21) on electrodeposited gold nanoparticles (AuNPs) on the printed gold surface, facilitating specific miR-21 capture. The hybridization of ssDNA-21 with miR-21 increases the anionic barrier density, impeding electron transfer from the redox probe and resulting in a current suppression that correlates with miR-21 concentration. The biosensor exhibited a linear detection range from 1 fM to 1 nM miR-21 with a sensitivity of 7.69 fM µA−1 cm2 and a rapid response time (15 min). With a low detection limit of 0.35 fM miR-21 in serum, the biosensor also demonstrates excellent selectivity against interferent species. This study introduces an electrochemical paper-based biosensor that uses gold inkjet printing to precisely detect miR-21, a key biomarker overexpressed in various cancers. This innovative device highlights the potential for cost-effective, accessible cancer diagnostics in underserved areas. Full article
(This article belongs to the Special Issue Nano Biosensors and Their Applications for In Vivo/Vitro Diagnosis—2nd Edition)
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24 pages, 13114 KiB  
Review
Recent Advances in Natural-Polymer-Based Hydrogels for Body Movement and Biomedical Monitoring
by Jing Liu, Saisai Li, Shuoze Li, Jinyue Tian, Hang Li, Zhifeng Pan, Lijun Lu and Yanchao Mao
Biosensors 2024, 14(9), 415; https://doi.org/10.3390/bios14090415 - 27 Aug 2024
Cited by 3 | Viewed by 2439
Abstract
In recent years, the interest in medical monitoring for human health has been rapidly increasing due to widespread concern. Hydrogels are widely used in medical monitoring and other fields due to their excellent mechanical properties, electrical conductivity and adhesion. However, some of the [...] Read more.
In recent years, the interest in medical monitoring for human health has been rapidly increasing due to widespread concern. Hydrogels are widely used in medical monitoring and other fields due to their excellent mechanical properties, electrical conductivity and adhesion. However, some of the non-degradable materials in hydrogels may cause some environmental damage and resource waste. Therefore, organic renewable natural polymers with excellent properties of biocompatibility, biodegradability, low cost and non-toxicity are expected to serve as an alternative to those non-degradable materials, and also provide a broad application prospect for the development of natural-polymer-based hydrogels as flexible electronic devices. This paper reviews the progress of research on many different types of natural-polymer-based hydrogels such as proteins and polysaccharides. The applications of natural-polymer-based hydrogels in body movement detection and biomedical monitoring are then discussed. Finally, the present challenges and future prospects of natural polymer-based hydrogels are summarized. Full article
(This article belongs to the Special Issue Artificial Skins and Wearable Biosensors for Healthcare Monitoring)
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37 pages, 7820 KiB  
Review
Recent Advances in Dielectrophoretic Manipulation and Separation of Microparticles and Biological Cells
by Junzhu Yao, Kai Zhao, Jia Lou and Kaihuan Zhang
Biosensors 2024, 14(9), 417; https://doi.org/10.3390/bios14090417 - 27 Aug 2024
Cited by 8 | Viewed by 6273
Abstract
Dielectrophoresis (DEP) is an advanced microfluidic manipulation technique that is based on the interaction of polarized particles with the spatial gradient of a non-uniform electric field to achieve non-contact and highly selective manipulation of particles. In recent years, DEP has made remarkable progress [...] Read more.
Dielectrophoresis (DEP) is an advanced microfluidic manipulation technique that is based on the interaction of polarized particles with the spatial gradient of a non-uniform electric field to achieve non-contact and highly selective manipulation of particles. In recent years, DEP has made remarkable progress in the field of microfluidics, and it has gradually transitioned from laboratory-scale research to high-throughput manipulation in practical applications. This paper reviews the recent advances in dielectric manipulation and separation of microparticles and biological cells and discusses in detail the design of chip structures for the two main methods, direct current dielectrophoresis (DC-DEP) and alternating current dielectrophoresis (AC-DEP). The working principles, technical implementation details, and other improved designs of electrode-based and insulator-based chips are summarized. Functional customization of DEP systems with specific capabilities, including separation, capture, purification, aggregation, and assembly of particles and cells, is then performed. The aim of this paper is to provide new ideas for the design of novel DEP micro/nano platforms with the desired high throughput for further development in practical applications. Full article
(This article belongs to the Special Issue Advanced Lab-on-Chip and Micro-systems for Manipulation and Bio-Detection)
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13 pages, 3302 KiB  
Article
Solid-Phase Electrochemiluminescence Enzyme Electrodes Based on Nanocage Arrays for Highly Sensitive Detection of Cholesterol
by Xinying Ma, Zhe Zhang, Yanyan Zheng and Jiyang Liu
Biosensors 2024, 14(8), 403; https://doi.org/10.3390/bios14080403 - 21 Aug 2024
Cited by 17 | Viewed by 1511
Abstract
The convenient and sensitive detection of metabolites is of great significance for understanding human health status and drug development. Solid-phase electrochemiluminescence (ECL) enzyme electrodes show great potential in metabolite detection based on the enzyme-catalyzed reaction product hydrogen peroxide (H2O2). [...] Read more.
The convenient and sensitive detection of metabolites is of great significance for understanding human health status and drug development. Solid-phase electrochemiluminescence (ECL) enzyme electrodes show great potential in metabolite detection based on the enzyme-catalyzed reaction product hydrogen peroxide (H2O2). Herein, a solid-phase ECL enzyme sensor was fabricated based on a confined emitter and an immobilized enzyme using electrostatic nanocage array, constructing a platform for the sensitive detection of cholesterol. The electrostatic cage nanochannel consists of a bipolar and bilayer vertically aligned mesoporous silica film (bp-VMSF). The upper layer of bp-VMSF is an amino-modified, positively charged VMSF (p-VMSF), and the lower layer is a negatively charged VMSF (n-VMSF). The most commonly used ECL probe tris(bipyridine)ruthenium(II) (Ru(bpy)32+) is fixed in n-VMSF by electrostatic adsorption from n-VMSF and electrostatic repulsion from the upper p-VMSF, generating significantly enhanced and stable ECL signals. The successful preparation of the electrostatic cage was characterized by scanning electron microscopy (SEM) and electrochemical methods. After amino groups on the outer surface of bp-VMSF were derivatized with aldehyde, cholesterol oxidase (ChOx) molecules were covalently immobilized. The successful construction of the enzyme electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). When the corresponding enzyme substrate, cholesterol, was present in the solution, the ECL signal of Ru(bpy)32+ was quenched by the enzyme-catalyzed reaction product H2O2, enabling the high-sensitivity detection of cholesterol. The linear range for detecting cholesterol was from 0.05 mM to 5.0 mM, with a limit of detection (LOD) of 1.5 μM. Full article
(This article belongs to the Special Issue Electrochemical and Fluorescent Biosensors: Novel Strategies, Methods, and Materials II)
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17 pages, 1670 KiB  
Article
Electrotactile BCI for Top-Down Somatosensory Training: Clinical Feasibility Trial of Online BCI Control in Subacute Stroke Patients
by Andrej M. Savić, Marija Novičić, Vera Miler-Jerković, Olivera Djordjević and Ljubica Konstantinović
Biosensors 2024, 14(8), 368; https://doi.org/10.3390/bios14080368 - 28 Jul 2024
Cited by 3 | Viewed by 4454
Abstract
This study investigates the feasibility of a novel brain–computer interface (BCI) device designed for sensory training following stroke. The BCI system administers electrotactile stimuli to the user’s forearm, mirroring classical sensory training interventions. Concurrently, selective attention tasks are employed to modulate electrophysiological brain [...] Read more.
This study investigates the feasibility of a novel brain–computer interface (BCI) device designed for sensory training following stroke. The BCI system administers electrotactile stimuli to the user’s forearm, mirroring classical sensory training interventions. Concurrently, selective attention tasks are employed to modulate electrophysiological brain responses (somatosensory event-related potentials—sERPs), reflecting cortical excitability in related sensorimotor areas. The BCI identifies attention-induced changes in the brain’s reactions to stimulation in an online manner. The study protocol assesses the feasibility of online binary classification of selective attention focus in ten subacute stroke patients. Each experimental session includes a BCI training phase for data collection and classifier training, followed by a BCI test phase to evaluate online classification of selective tactile attention based on sERP. During online classification tests, patients complete 20 repetitions of selective attention tasks with feedback on attention focus recognition. Using a single electroencephalographic channel, attention classification accuracy ranges from 70% to 100% across all patients. The significance of this novel BCI paradigm lies in its ability to quantitatively measure selective tactile attention resources throughout the therapy session, introducing a top-down approach to classical sensory training interventions based on repeated neuromuscular electrical stimulation. Full article
(This article belongs to the Section Biosensors and Healthcare)
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12 pages, 2956 KiB  
Article
Nanosensor-Enabled Detection and Identification of Intracellular Bacterial Infections in Macrophages
by Aritra Nath Chattopadhyay, Mingdi Jiang, Jessa Marie V. Makabenta, Jungmi Park, Yingying Geng and Vincent Rotello
Biosensors 2024, 14(8), 360; https://doi.org/10.3390/bios14080360 - 25 Jul 2024
Cited by 3 | Viewed by 2494
Abstract
Opportunistic bacterial pathogens can evade the immune response by residing and reproducing within host immune cells, including macrophages. These intracellular infections provide reservoirs for pathogens that enhance the progression of infections and inhibit therapeutic strategies. Current sensing strategies for intracellular infections generally use [...] Read more.
Opportunistic bacterial pathogens can evade the immune response by residing and reproducing within host immune cells, including macrophages. These intracellular infections provide reservoirs for pathogens that enhance the progression of infections and inhibit therapeutic strategies. Current sensing strategies for intracellular infections generally use immunosensing of specific biomarkers on the cell surface or polymerase chain reaction (PCR) of the corresponding nucleic acids, making detection difficult, time-consuming, and challenging to generalize. Intracellular infections can induce changes in macrophage glycosylation, providing a potential strategy for signature-based detection of intracellular infections. We report here the detection of bacterial infection in macrophages using a boronic acid (BA)-based pH-responsive polymer sensor array engineered to distinguish mammalian cell phenotypes by their cell surface glycosylation signatures. The sensor was able to discriminate between different infecting bacteria in minutes, providing a promising tool for diagnostic and screening applications. Full article
(This article belongs to the Special Issue Microbial Biosensor: From Design to Applications)
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37 pages, 7541 KiB  
Review
AI-Assisted Detection of Biomarkers by Sensors and Biosensors for Early Diagnosis and Monitoring
by Tomasz Wasilewski, Wojciech Kamysz and Jacek Gębicki
Biosensors 2024, 14(7), 356; https://doi.org/10.3390/bios14070356 - 22 Jul 2024
Cited by 42 | Viewed by 6584
Abstract
The steady progress in consumer electronics, together with improvement in microflow techniques, nanotechnology, and data processing, has led to implementation of cost-effective, user-friendly portable devices, which play the role of not only gadgets but also diagnostic tools. Moreover, numerous smart devices monitor patients’ [...] Read more.
The steady progress in consumer electronics, together with improvement in microflow techniques, nanotechnology, and data processing, has led to implementation of cost-effective, user-friendly portable devices, which play the role of not only gadgets but also diagnostic tools. Moreover, numerous smart devices monitor patients’ health, and some of them are applied in point-of-care (PoC) tests as a reliable source of evaluation of a patient’s condition. Current diagnostic practices are still based on laboratory tests, preceded by the collection of biological samples, which are then tested in clinical conditions by trained personnel with specialistic equipment. In practice, collecting passive/active physiological and behavioral data from patients in real time and feeding them to artificial intelligence (AI) models can significantly improve the decision process regarding diagnosis and treatment procedures via the omission of conventional sampling and diagnostic procedures while also excluding the role of pathologists. A combination of conventional and novel methods of digital and traditional biomarker detection with portable, autonomous, and miniaturized devices can revolutionize medical diagnostics in the coming years. This article focuses on a comparison of traditional clinical practices with modern diagnostic techniques based on AI and machine learning (ML). The presented technologies will bypass laboratories and start being commercialized, which should lead to improvement or substitution of current diagnostic tools. Their application in PoC settings or as a consumer technology accessible to every patient appears to be a real possibility. Research in this field is expected to intensify in the coming years. Technological advancements in sensors and biosensors are anticipated to enable the continuous real-time analysis of various omics fields, fostering early disease detection and intervention strategies. The integration of AI with digital health platforms would enable predictive analysis and personalized healthcare, emphasizing the importance of interdisciplinary collaboration in related scientific fields. Full article
(This article belongs to the Special Issue Microfluidic Biosensing Technologies for Point-of-Care Applications)
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35 pages, 3384 KiB  
Review
Boosting Electrochemical Sensing Performances Using Molecularly Imprinted Nanoparticles
by Francesco Gagliani, Tiziano Di Giulio, Muhammad Ibrar Asif, Cosimino Malitesta and Elisabetta Mazzotta
Biosensors 2024, 14(7), 358; https://doi.org/10.3390/bios14070358 - 22 Jul 2024
Cited by 5 | Viewed by 2792
Abstract
Nanoparticles of molecularly imprinted polymers (nanoMIPs) combine the excellent recognition ability of imprinted polymers with specific properties related to the nanosize, such as a high surface-to-volume ratio, resulting in highly performing recognition elements with surface-exposed binding sites that promote the interaction with the [...] Read more.
Nanoparticles of molecularly imprinted polymers (nanoMIPs) combine the excellent recognition ability of imprinted polymers with specific properties related to the nanosize, such as a high surface-to-volume ratio, resulting in highly performing recognition elements with surface-exposed binding sites that promote the interaction with the target and, in turn, binding kinetics. Different synthetic strategies are currently available to produce nanoMIPs, with the possibility to select specific conditions in relation to the nature of monomers/templates and, importantly, to tune the nanoparticle size. The excellent sensing properties, combined with the size, tunability, and flexibility of synthetic protocols applicable to different targets, have enabled the widespread use of nanoMIPs in several applications, including sensors, imaging, and drug delivery. The present review summarizes nanoMIPs applications in sensors, specifically focusing on electrochemical detection, for which nanoMIPs have been mostly applied. After a general survey of the most widely adopted nanoMIP synthetic approaches, the integration of imprinted nanoparticles with electrochemical transducers will be discussed, representing a key step for enabling a reliable and stable sensor response. The mechanisms for electrochemical signal generation will also be compared, followed by an illustration of nanoMIP-based electrochemical sensor employment in several application fields. The high potentialities of nanoMIP-based electrochemical sensors are presented, and possible reasons that still limit their commercialization and issues to be resolved for coupling electrochemical sensing and nanoMIPs in an increasingly widespread daily-use technology are discussed. Full article
(This article belongs to the Special Issue Nanotechnology-Enabled Biosensors)
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19 pages, 5361 KiB  
Review
Aptamer Screening: Current Methods and Future Trend towards Non-SELEX Approach
by Zhihui Fang, Xiaorui Feng, Fan Tang, Han Jiang, Shuyuan Han, Ran Tao and Chenze Lu
Biosensors 2024, 14(7), 350; https://doi.org/10.3390/bios14070350 - 18 Jul 2024
Cited by 9 | Viewed by 3941
Abstract
Aptamers are nucleic acid sequences that specifically bind with target molecules and are vital to applications such as biosensing, drug development, disease diagnostics, etc. The traditional selection procedure of aptamers is based on the Systematic Evolution of Ligands by an Exponential Enrichment (SELEX) [...] Read more.
Aptamers are nucleic acid sequences that specifically bind with target molecules and are vital to applications such as biosensing, drug development, disease diagnostics, etc. The traditional selection procedure of aptamers is based on the Systematic Evolution of Ligands by an Exponential Enrichment (SELEX) process, which relies on repeating cycles of screening and amplification. With the rapid development of aptamer applications, RNA and XNA aptamers draw more attention than before. But their selection is troublesome due to the necessary reverse transcription and transcription process (RNA) or low efficiency and accuracy of enzymes for amplification (XNA). In light of this, we review the recent advances in aptamer selection methods and give an outlook on future development in a non-SELEX approach, which simplifies the procedure and reduces the experimental costs. We first provide an overview of the traditional SELEX methods mostly designed for screening DNA aptamers to introduce the common tools and methods. Then a section on the current screening methods for RNA and XNA is prepared to demonstrate the efforts put into screening these aptamers and the current difficulties. We further predict that the future trend of aptamer selection lies in non-SELEX methods that do not require nucleic acid amplification. We divide non-SELEX methods into an immobilized format and non-immobilized format and discuss how high-resolution partitioning methods could facilitate the further improvement of selection efficiency and accuracy. Full article
(This article belongs to the Special Issue Nano Biosensors and Their Applications for In Vivo/Vitro Diagnosis—2nd Edition)
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15 pages, 3010 KiB  
Article
Enhanced Point-of-Care SARS-CoV-2 Detection: Integrating RT-LAMP with Microscanning
by Minkyeong Choi, Eunji Lee, Seoyeon Park, Chae-Seung Lim and Woong-Sik Jang
Biosensors 2024, 14(7), 348; https://doi.org/10.3390/bios14070348 - 17 Jul 2024
Cited by 3 | Viewed by 1503
Abstract
The COVID-19 pandemic has highlighted the urgent need for rapid and accurate diagnostic methods for various infectious diseases, including SARS-CoV-2. Traditional RT-PCR methods, while highly sensitive and specific, require complex equipment and skilled personnel. In response, we developed an integrated RT-LAMP-MS assay, which [...] Read more.
The COVID-19 pandemic has highlighted the urgent need for rapid and accurate diagnostic methods for various infectious diseases, including SARS-CoV-2. Traditional RT-PCR methods, while highly sensitive and specific, require complex equipment and skilled personnel. In response, we developed an integrated RT-LAMP-MS assay, which combines rapid reverse transcription loop-mediated isothermal amplification (RT-LAMP) with microscanning (MS) technology for detecting SARS-CoV-2. The assay uses magnesium pyrophosphate formed during LAMP amplification as a visual marker, allowing direct observation via microscopy without the need for additional chemical indicators or probes. For the SARS-CoV-2/IC RT-LAMP-MS assay, the sample-LAMP reagent mixture was added to a microchip with SARS-CoV-2 primers and internal controls, then incubated at 62 °C for 30 min in a heat block, followed by amplification analysis using a microscanner. In clinical tests, the RT-LAMP-MS assay showed 99% sensitivity and 100% specificity, which is identical to the RT-LAMP results and comparable to the commercial AllplexTM SARS-CoV-2 assay results. Additionally, the limit of detection (LOD) was determined to be 10−1 PFU mL−1 (dynamic range: 103~10−1 PFU mL−1). The assay delivers results in 30 min, uses low-cost equipment, and demonstrates 100% reproducibility in repeated tests, making it suitable for point-of-care use in resource-limited settings. Full article
(This article belongs to the Special Issue Recent Advance in Biosensors and Its Applications in Point-of-Care Molecular Diagnostics (POC-MDx))
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22 pages, 6502 KiB  
Review
Beta-Barrel Nanopores as Diagnostic Sensors: An Engineering Perspective
by Rani Wiswedel, Anh Thi Ngoc Bui, Jinhyung Kim and Mi-Kyung Lee
Biosensors 2024, 14(7), 345; https://doi.org/10.3390/bios14070345 - 16 Jul 2024
Cited by 4 | Viewed by 2469
Abstract
Biological nanopores are ultrasensitive and highly attractive platforms for disease diagnostics, including the sequencing of viral and microbial genes and the detection of biomarkers and pathogens. To utilize biological nanopores as diagnostic sensors, they have been engineered through various methods resulting in the [...] Read more.
Biological nanopores are ultrasensitive and highly attractive platforms for disease diagnostics, including the sequencing of viral and microbial genes and the detection of biomarkers and pathogens. To utilize biological nanopores as diagnostic sensors, they have been engineered through various methods resulting in the accurate and highly sensitive detection of biomarkers and disease-related biomolecules. Among diverse biological nanopores, the β-barrel-containing nanopores have advantages in nanopore engineering because of their robust structure, making them well-suited for modifications. In this review, we highlight the engineering approaches for β-barrel-containing nanopores used in single-molecule sensing for applications in early diagnosis and prognosis. In the highlighted studies, β-barrel nanopores can be modified by genetic mutation to change the structure; alter charge distributions; or add enzymes, aptamers, and protein probes to enhance sensitivity and accuracy. Furthermore, this review discusses challenges and future perspectives for advancing nanopore-based diagnostic sensors. Full article
(This article belongs to the Section Biosensor and Bioelectronic Devices)
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23 pages, 3403 KiB  
Review
Recent Progress in Organic Electrochemical Transistor-Structured Biosensors
by Zhuotao Hu, Yingchao Hu, Lu Huang, Wei Zhong, Jianfeng Zhang, Dengyun Lei, Yayi Chen, Yao Ni and Yuan Liu
Biosensors 2024, 14(7), 330; https://doi.org/10.3390/bios14070330 - 4 Jul 2024
Cited by 6 | Viewed by 2516
Abstract
The continued advancement of organic electronic technology will establish organic electrochemical transistors as pivotal instruments in the field of biological detection. Here, we present a comprehensive review of the state-of-the-art technology and advancements in the use of organic electrochemical transistors as biosensors. This [...] Read more.
The continued advancement of organic electronic technology will establish organic electrochemical transistors as pivotal instruments in the field of biological detection. Here, we present a comprehensive review of the state-of-the-art technology and advancements in the use of organic electrochemical transistors as biosensors. This review provides an in-depth analysis of the diverse modification materials, methods, and mechanisms utilized in organic electrochemical transistor-structured biosensors (OETBs) for the selective detection of a wide range of target analyte encompassing electroactive species, electro-inactive species, and cancer cells. Recent advances in OETBs for use in sensing systems and wearable and implantable applications are also briefly introduced. Finally, challenges and opportunities in the field are discussed. Full article
(This article belongs to the Special Issue Advances in FET-Based Biosensors and Neuromorphic Devices: Exploring Artificial Perception and Biomimetic Sensing)
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13 pages, 7891 KiB  
Review
Fueling the Future: The Emergence of Self-Powered Enzymatic Biofuel Cell Biosensors
by Akhilesh Kumar Gupta and Alexey Viktorovich Krasnoslobodtsev
Biosensors 2024, 14(7), 316; https://doi.org/10.3390/bios14070316 - 24 Jun 2024
Cited by 4 | Viewed by 2784
Abstract
Self-powered biosensors are innovative devices that can detect and analyze biological or chemical substances without the need for an external power source. These biosensors can convert energy from the surrounding environment or the analyte itself into electrical signals for sensing and data transmission. [...] Read more.
Self-powered biosensors are innovative devices that can detect and analyze biological or chemical substances without the need for an external power source. These biosensors can convert energy from the surrounding environment or the analyte itself into electrical signals for sensing and data transmission. The self-powered nature of these biosensors offers several advantages, such as portability, autonomy, and reduced waste generation from disposable batteries. They find applications in various fields, including healthcare, environmental monitoring, food safety, and wearable devices. While self-powered biosensors are a promising technology, there are still challenges to address, such as improving energy efficiency, sensitivity, and stability to make them more practical and widely adopted. This review article focuses on exploring the evolving trends in self-powered biosensor design, outlining potential advantages and limitations. With a focal point on enzymatic biofuel cell power generation, this article describes various sensing mechanisms that employ the analyte as substrate or fuel for the biocatalyst’s ability to generate current. Technical aspects of biofuel cells are also examined. Research and development in the field of self-powered biosensors is ongoing, and this review describes promising areas for further exploration within the field, identifying underexplored areas that could benefit from further investigation. Full article
(This article belongs to the Special Issue Trends in Development of Biosensors for Disease Diagnosis, Treatment and Management—2nd Edition)
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16 pages, 6549 KiB  
Article
Integrated High-Throughput Centrifugal Microfluidic Chip Device for Pathogen Detection On-Site
by Shuyu Lu, Yuanzhan Yang, Siqi Cui, Anyi Li, Cheng Qian and Xiaoqiong Li
Biosensors 2024, 14(6), 313; https://doi.org/10.3390/bios14060313 - 19 Jun 2024
Cited by 5 | Viewed by 2285
Abstract
An integrated and high-throughput device for pathogen detection is crucial in point-of-care testing (POCT), especially for early diagnosis of infectious diseases and preventing the spread of infection. We developed an on-site testing platform that utilizes a centrifugal microfluidic chip and automated device to [...] Read more.
An integrated and high-throughput device for pathogen detection is crucial in point-of-care testing (POCT), especially for early diagnosis of infectious diseases and preventing the spread of infection. We developed an on-site testing platform that utilizes a centrifugal microfluidic chip and automated device to achieve high-throughput detection. The low-power (<32 W), portable (220 mm × 220 mm × 170 mm, 4 kg) device can complete bacterial lysis, nucleic acid extraction and purification, loop-mediated isothermal amplification (LAMP) reaction, and real-time fluorescence detection. Magnetic beads for nucleic acid adsorption can be mixed by applying electromagnetic fields and centrifugal forces, and the efficiency of nucleic acid extraction is improved by 60% compared to the no-mixing group. The automated nucleic acid extraction process achieves equivalent nucleic acid extraction efficiency in only 40% of the time consumed using the kit protocol. By designing the valve system and disc layout, the maximum speed required for the centrifugal microfluidic chip is reduced to 1500 rpm, greatly reducing the equipment power consumption and size. In detecting E. coli, our platform achieves a limit of detection (LOD) of 102 CFU/mL in 60 min. In summary, our active centrifugal microfluidic platform provides a solution for the integration of complex biological assays on turntables, with great potential in the application of point-of-care diagnosis. Full article
(This article belongs to the Special Issue Biosensing Technologies in Medical Diagnosis)
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18 pages, 4421 KiB  
Article
Colorimetric Glucose Biosensor Based on Chitosan Films and Its Application for Glucose Detection in Beverages Using a Smartphone Application
by Anastasia Skonta, Myrto G. Bellou, Theodore E. Matikas and Haralambos Stamatis
Biosensors 2024, 14(6), 299; https://doi.org/10.3390/bios14060299 - 7 Jun 2024
Cited by 3 | Viewed by 2087
Abstract
Nowadays, biosensors are gaining increasing interest in foods’ and beverages’ quality control, owing to their economic production, enhanced sensitivity, specificity, and faster analysis. In particular, colorimetric biosensors can be combined with color recognition applications on smartphones for the detection of analytes, rendering the [...] Read more.
Nowadays, biosensors are gaining increasing interest in foods’ and beverages’ quality control, owing to their economic production, enhanced sensitivity, specificity, and faster analysis. In particular, colorimetric biosensors can be combined with color recognition applications on smartphones for the detection of analytes, rendering the whole procedure more applicable in everyday life. Herein, chitosan (CS) films were prepared with the deep eutectic solvent (DES) choline chloride/urea/glycerol (ChCl:U:Gly). Glucose oxidase (GOx), a widely utilized enzyme in quality control, was immobilized within CS films through glutaraldehyde (GA), leading to the formation of CS/GOx films. The optimized GOx concentration and DES content were determined for the films. Moreover, the effect of the pH and temperature of the glucose oxidation reaction on the enzymatic activity of GOx was studied. The structure, stability, and specificity of the CS/GOx films as well as the Km values of free and immobilized GOx were also determined. Finally, the analytical performance of the films was studied by using both a spectrophotometer and a color recognition application on a smartphone. The results demonstrated that the films were highly accurate, specific to glucose, and stable when stored at 4 °C for 4 weeks and when reused 10 times, without evident activity loss. Furthermore, the films displayed a good linear response range (0.1–0.8 mM) and a good limit of detection (LOD, 33 μM), thus being appropriate for the estimation of glucose concentration in real samples through a smartphone application. Full article
(This article belongs to the Special Issue Biosensing, Biosafety and Diagnosis)
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18 pages, 8646 KiB  
Article
Multifunctional Three-in-One Sensor on t-ZnO for Ultraviolet and VOC Sensing for Bioengineering Applications
by Rajat Nagpal, Cristian Lupan, Adrian Bîrnaz, Alexandr Sereacov, Erik Greve, Monja Gronenberg, Leonard Siebert, Rainer Adelung and Oleg Lupan
Biosensors 2024, 14(6), 293; https://doi.org/10.3390/bios14060293 - 5 Jun 2024
Cited by 3 | Viewed by 2241
Abstract
Zinc oxide (ZnO) is considered to be one of the most explored and reliable sensing materials for UV detection due to its excellent properties, like a wide band gap and high exciton energy. Our current study on a photodetector based on tetrapodal ZnO [...] Read more.
Zinc oxide (ZnO) is considered to be one of the most explored and reliable sensing materials for UV detection due to its excellent properties, like a wide band gap and high exciton energy. Our current study on a photodetector based on tetrapodal ZnO (t-ZnO) reported an extremely high UV response of ~9200 for 394 nm UV illumination at 25 °C. The t-ZnO network structure and morphology were investigated using XRD and SEM. The sensor showed a UV/visible ratio of ~12 at 25 °C for 394 nm UV illumination and 443 nm visible illumination. By increasing the temperature, monotonic decreases in response and recovery time were observed. By increasing the bias voltage, the response time was found to decrease while the recovery time was increased. The maximum responsivity shifted to higher wavelengths from 394 nm to 400 nm by increasing the operating temperature from 25 °C to 100 °C. The t-ZnO networks exhibited gas-sensing performances at temperatures above 250 °C, and a maximum response of ~1.35 was recorded at 350 °C with a good repeatability and fast recovery in 16 s for 100 ppm of n-butanol vapor. This study demonstrated that t-ZnO networks are good biosensors that can be used for diverse biomedical applications like the sensing of VOCs (volatile organic compounds) and ultraviolet detection under a wide range of temperatures, and may find new possibilities in biosensing applications. Full article
(This article belongs to the Special Issue Electrochemical (Bio-) Sensors in Biological Applications—2nd Edition)
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18 pages, 11054 KiB  
Article
Development of a Tetherless Bioimpedance Device That Uses Morphologic Changes to Predict Blood Flow Restrictions Mimicking Peripheral Artery Disease Progression
by Sungcheol Hong and Gerard Coté
Biosensors 2024, 14(6), 286; https://doi.org/10.3390/bios14060286 - 1 Jun 2024
Cited by 3 | Viewed by 2761
Abstract
A tetherless multi-targeted bioimpedance device was designed, modeled, built, and tested for measuring arterial pulse and, using morphological analysis, its potential for monitoring blood flow restrictions that mimic Peripheral Artery Disease (PAD) was assessed across multiple peripheral arteries. Specifically, we first developed a [...] Read more.
A tetherless multi-targeted bioimpedance device was designed, modeled, built, and tested for measuring arterial pulse and, using morphological analysis, its potential for monitoring blood flow restrictions that mimic Peripheral Artery Disease (PAD) was assessed across multiple peripheral arteries. Specifically, we first developed a small form factor, tetherless, bioimpedance device, based on high-frequency structure simulator (HFSS) simulations. After designing and building the device we then tested it in vivo on human subjects on multiple arteries and found that we did not need to modify the gain on the device compared to the bench top system. Further, it was found that changes in the morphology of the bioimpedance signal over time, depicted through the ratio of the first and second harmonic in the signal frequency, could be used to predict blood flow restrictions that mimic peripheral artery disease (PAD). The HFSS simulations helped guide the modulation frequency selection and the placement of the bioimpedance electrodes. We built the device and compared it to two commercially available bioimpedance devices and it was shown to demonstrate a distinct advantage in its multi-target capability, enabling more accurate pulse measurements from different arteries without the need for tuning the circuit for each artery. Comparing the ratio of the 1st and 2nd harmonics as a function of the blood flow restriction, the two commercial devices showed a maximum error across arteries of between 22% and 27% depending on the measurement location, whereas our system consistently displayed a stable value of just below 4%. With this system, there is the potential for comprehensive and personalized medical examinations for PAD at the point of care (POC). Full article
(This article belongs to the Section Biosensors and Healthcare)
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11 pages, 7827 KiB  
Communication
Morphology Control of Zr-Based Luminescent Metal-Organic Frameworks for Aflatoxin B1 Detection
by Fang Zhu, Qiuxue Chai, Dinghui Xiong, Nuanfei Zhu, Jialong Zhou, Ruoxi Wu and Zhen Zhang
Biosensors 2024, 14(6), 273; https://doi.org/10.3390/bios14060273 - 27 May 2024
Cited by 4 | Viewed by 1352
Abstract
Metal–organic frameworks (MOFs) have gained significant prominence as sensing materials owing to their unique properties. However, understanding the correlation between the morphology, properties, and sensing performance in these MOF-based sensors remains a challenge, limiting their applications and potential for improvement. In this study, [...] Read more.
Metal–organic frameworks (MOFs) have gained significant prominence as sensing materials owing to their unique properties. However, understanding the correlation between the morphology, properties, and sensing performance in these MOF-based sensors remains a challenge, limiting their applications and potential for improvement. In this study, Zr-MOF was chosen as an ideal model to explore the impact of the MOF morphology on the sensing performance, given its remarkable stability and structural variability. Three luminescent MOFs (namely rod-like Zr-LMOF, prismoid-like Zr-LMOF, and ellipsoid-like Zr-LMOF) were synthesized by adjusting the quantities of the benzoic acid and the reaction time. More importantly, the sensing performance of these Zr-LMOFs in response to aflatoxin B1 (AFB1) was thoroughly examined. Notably, the ellipsoid-like Zr-LMOF exhibited significantly higher sensitivity compared to other Zr-LMOFs, attributed to its large specific surface area and pore volume. Additionally, an in-depth investigation into the detection mechanism of AFB1 by Zr-LMOFs was conducted. Building upon these insights, a ratiometric fluorescence sensor was developed by coordinating Eu3+ with ellipsoid-like Zr-LMOF, achieving a remarkably lower detection limit of 2.82 nM for AFB1. This study contributes to an improved comprehension of the relationship between the MOF morphology and the sensing characteristics while presenting an effective approach for AFB1 detection. Full article
(This article belongs to the Special Issue Advanced Nanozyme for Biosensors)
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12 pages, 1127 KiB  
Article
Optimization of Microfluidics for Point-of-Care Blood Sensing
by Amirmahdi Tavakolidakhrabadi, Matt Stark, Ulrike Bacher, Myriam Legros and Cedric Bessire
Biosensors 2024, 14(6), 266; https://doi.org/10.3390/bios14060266 - 23 May 2024
Cited by 3 | Viewed by 1862
Abstract
Blood tests are widely used in modern medicine to diagnose certain illnesses and evaluate the overall health of a patient. To enable testing in resource-limited areas, there has been increasing interest in point-of-care (PoC) testing devices. To process blood samples, liquid mixing with [...] Read more.
Blood tests are widely used in modern medicine to diagnose certain illnesses and evaluate the overall health of a patient. To enable testing in resource-limited areas, there has been increasing interest in point-of-care (PoC) testing devices. To process blood samples, liquid mixing with active pumps is usually required, making PoC blood testing expensive and bulky. We explored the possibility of processing approximately 2 μL of whole blood for image flow cytometry using capillary structures that allowed test times of a few minutes without active pumps. Capillary pump structures with five different pillar shapes were simulated using Ansys Fluent to determine which resulted in the fastest whole blood uptake. The simulation results showed a strong influence of the capillary pump pillar shape on the chip filling time. Long and thin structures with a high aspect ratio exhibited faster filling times. Microfluidic chips using the simulated pump design with the most efficient blood uptake were fabricated with polydimethylsiloxane (PDMS) and polyethylene oxide (PEO). The chip filling times were tested with 2 μL of both water and whole blood, resulting in uptake times of 24 s for water and 111 s for blood. The simulated blood plasma results deviated from the experimental filling times by about 35% without accounting for any cell-induced effects. By comparing the flow speed induced by different pump pillar geometries, this study offers insights for the design and optimization of passive microfluidic devices for inhomogenous liquids such as whole blood in sensing applications. Full article
(This article belongs to the Section Biosensors and Healthcare)
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23 pages, 1025 KiB  
Article
Parkinson’s Disease Recognition Using Decorrelated Convolutional Neural Networks: Addressing Imbalance and Scanner Bias in rs-fMRI Data
by Pranita Patil and W. Randolph Ford
Biosensors 2024, 14(5), 259; https://doi.org/10.3390/bios14050259 - 19 May 2024
Cited by 4 | Viewed by 2179
Abstract
Parkinson’s disease (PD) is a neurodegenerative and progressive disease that impacts the nerve cells in the brain and varies from person to person. The exact cause of PD is still unknown, and the diagnosis of PD does not include a specific objective test [...] Read more.
Parkinson’s disease (PD) is a neurodegenerative and progressive disease that impacts the nerve cells in the brain and varies from person to person. The exact cause of PD is still unknown, and the diagnosis of PD does not include a specific objective test with certainty. Although deep learning has made great progress in medical neuroimaging analysis, these methods are very susceptible to biases present in neuroimaging datasets. An innovative decorrelated deep learning technique is introduced to mitigate class bias and scanner bias while simultaneously focusing on finding distinguishing characteristics in resting-state functional MRI (rs-fMRI) data, which assists in recognizing PD with good accuracy. The decorrelation function reduces the nonlinear correlation between features and bias in order to learn bias-invariant features. The publicly available Parkinson’s Progression Markers Initiative (PPMI) dataset, referred to as a single-scanner imbalanced dataset in this study, was used to validate our method. The imbalanced dataset problem affects the performance of the deep learning framework by overfitting to the majority class. To resolve this problem, we propose a new decorrelated convolutional neural network (DcCNN) framework by applying decorrelation-based optimization to convolutional neural networks (CNNs). An analysis of evaluation metrics comparisons shows that integrating the decorrelation function boosts the performance of PD recognition by removing class bias. Specifically, our DcCNN models perform significantly better than existing traditional approaches to tackle the imbalance problem. Finally, the same framework can be extended to create scanner-invariant features without significantly impacting the performance of a model. The obtained dataset is a multiscanner dataset, which leads to scanner bias due to the differences in acquisition protocols and scanners. The multiscanner dataset is a combination of two publicly available datasets, namely, PPMI and FTLDNI—the frontotemporal lobar degeneration neuroimaging initiative (NIFD) dataset. The results of t-distributed stochastic neighbor embedding (t-SNE) and scanner classification accuracy of our proposed feature extraction–DcCNN (FE-DcCNN) model validated the effective removal of scanner bias. Our method achieves an average accuracy of 77.80% on a multiscanner dataset for differentiating PD from a healthy control, which is superior to the DcCNN model trained on a single-scanner imbalanced dataset. Full article
(This article belongs to the Special Issue Biosensing and Imaging for Neurodegenerative Diseases)
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15 pages, 1221 KiB  
Review
Development of Non-Invasive Biosensors for Neonatal Jaundice Detection: A Review
by Chandan Jyoti Hazarika, Alee Borah, Poly Gogoi, Shrimanta S. Ramchiary, Bethuel Daurai, Manashjit Gogoi and Manob Jyoti Saikia
Biosensors 2024, 14(5), 254; https://doi.org/10.3390/bios14050254 - 17 May 2024
Cited by 3 | Viewed by 5174
Abstract
One of the most common problems many babies encounter is neonatal jaundice. The symptoms are yellowing of the skin or eyes because of bilirubin (from above 2.0 to 2.5 mg/dL in the blood). If left untreated, it can lead to serious neurological complications. [...] Read more.
One of the most common problems many babies encounter is neonatal jaundice. The symptoms are yellowing of the skin or eyes because of bilirubin (from above 2.0 to 2.5 mg/dL in the blood). If left untreated, it can lead to serious neurological complications. Traditionally, jaundice detection has relied on invasive blood tests, but developing non-invasive biosensors has provided an alternative approach. This systematic review aims to assess the advancement of these biosensors. This review discusses the many known invasive and non-invasive diagnostic modalities for detecting neonatal jaundice and their limitations. It also notes that the recent research and development on non-invasive biosensors for neonatal jaundice diagnosis is still in its early stages, with the majority of investigations being in vitro or at the pre-clinical level. Non-invasive biosensors could revolutionize neonatal jaundice detection; however, a number of issues still need to be solved before this can happen. These consist of in-depth validation studies, affordable and user-friendly gadgets, and regulatory authority approval. To create biosensors that meet regulatory requirements, additional research is required to make them more precise and affordable. Full article
(This article belongs to the Section Biosensors and Healthcare)
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28 pages, 5574 KiB  
Review
Double-Sided Tape in Microfluidics: A Cost-Effective Method in Device Fabrication
by Savanah Smith, Marzhan Sypabekova and Seunghyun Kim
Biosensors 2024, 14(5), 249; https://doi.org/10.3390/bios14050249 - 15 May 2024
Cited by 6 | Viewed by 4552
Abstract
The demand for easy-to-use, affordable, accessible, and reliable technology is increasing in biological, chemical, and medical research. Microfluidic devices have the potential to meet these standards by offering cost-effective, highly sensitive, and highly specific diagnostic tests with rapid performance and minimal sample volumes. [...] Read more.
The demand for easy-to-use, affordable, accessible, and reliable technology is increasing in biological, chemical, and medical research. Microfluidic devices have the potential to meet these standards by offering cost-effective, highly sensitive, and highly specific diagnostic tests with rapid performance and minimal sample volumes. Traditional microfluidic device fabrication methods, such as photolithography and soft lithography, are time-consuming and require specialized equipment and expertise, making them costly and less accessible to researchers and clinicians and limiting the applicability and potential of microfluidic devices. To address this, researchers have turned to using new low-cost materials, such as double-sided tape for microfluidic device fabrication, which offers simple and low-cost processes. The innovation of low-cost and easy-to-make microfluidic devices improves the potential for more devices to be transitioned from laboratories to commercialized products found in stores, offices, and homes. This review serves as a comprehensive summary of the growing interest in and use of double-sided tape-based microfluidic devices in the last 20 years. It discusses the advantages of using double-sided tape, the fabrication techniques used to create and bond microfluidic devices, and the limitations of this approach in certain applications. Full article
(This article belongs to the Special Issue Microfluidics and MEMS for Diagnostics and Biomedical Applications)
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27 pages, 2876 KiB  
Review
A Comprehensive Review of Organ-on-a-Chip Technology and Its Applications
by Negar Farhang Doost and Soumya K. Srivastava
Biosensors 2024, 14(5), 225; https://doi.org/10.3390/bios14050225 - 1 May 2024
Cited by 20 | Viewed by 14703
Abstract
Organ-on-a-chip (OOC) is an emerging technology that simulates an artificial organ within a microfluidic cell culture chip. Current cell biology research focuses on in vitro cell cultures due to various limitations of in vivo testing. Unfortunately, in-vitro cell culturing fails to provide an [...] Read more.
Organ-on-a-chip (OOC) is an emerging technology that simulates an artificial organ within a microfluidic cell culture chip. Current cell biology research focuses on in vitro cell cultures due to various limitations of in vivo testing. Unfortunately, in-vitro cell culturing fails to provide an accurate microenvironment, and in vivo cell culturing is expensive and has historically been a source of ethical controversy. OOC aims to overcome these shortcomings and provide the best of both in vivo and in vitro cell culture research. The critical component of the OOC design is utilizing microfluidics to ensure a stable concentration gradient, dynamic mechanical stress modeling, and accurate reconstruction of a cellular microenvironment. OOC also has the advantage of complete observation and control of the system, which is impossible to recreate in in-vivo research. Multiple throughputs, channels, membranes, and chambers are constructed in a polydimethylsiloxane (PDMS) array to simulate various organs on a chip. Various experiments can be performed utilizing OOC technology, including drug delivery research and toxicology. Current technological expansions involve multiple organ microenvironments on a single chip, allowing for studying inter-tissue interactions. Other developments in the OOC technology include finding a more suitable material as a replacement for PDMS and minimizing artefactual error and non-translatable differences. Full article
(This article belongs to the Section Nano- and Micro-Technologies in Biosensors)
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30 pages, 4958 KiB  
Review
Recent Advances in Aptamer-Based Biosensors for Bacterial Detection
by Vincent Léguillier, Brahim Heddi and Jasmina Vidic
Biosensors 2024, 14(5), 210; https://doi.org/10.3390/bios14050210 - 23 Apr 2024
Cited by 19 | Viewed by 7239
Abstract
The rapid and sensitive detection of pathogenic bacteria is becoming increasingly important for the timely prevention of contamination and the treatment of infections. Biosensors based on nucleic acid aptamers, integrated with optical, electrochemical, and mass-sensitive analytical techniques, have garnered intense interest because of [...] Read more.
The rapid and sensitive detection of pathogenic bacteria is becoming increasingly important for the timely prevention of contamination and the treatment of infections. Biosensors based on nucleic acid aptamers, integrated with optical, electrochemical, and mass-sensitive analytical techniques, have garnered intense interest because of their versatility, cost-efficiency, and ability to exhibit high affinity and specificity in binding bacterial biomarkers, toxins, and whole cells. This review highlights the development of aptamers, their structural characterization, and the chemical modifications enabling optimized recognition properties and enhanced stability in complex biological matrices. Furthermore, recent examples of aptasensors for the detection of bacterial cells, biomarkers, and toxins are discussed. Finally, we explore the barriers to and discuss perspectives on the application of aptamer-based bacterial detection. Full article
(This article belongs to the Special Issue Nano Biosensor and Its Application for In Vivo/Vitro Diagnosis)
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19 pages, 2525 KiB  
Review
Recent Advances in Lateral Flow Assays for Viral Protein Detection with Nanomaterial-Based Optical Sensors
by Min Jung Kim, Izzati Haizan, Min Ju Ahn, Dong-Hyeok Park and Jin-Ha Choi
Biosensors 2024, 14(4), 197; https://doi.org/10.3390/bios14040197 - 17 Apr 2024
Cited by 9 | Viewed by 4846
Abstract
Controlling the progression of contagious diseases is crucial for public health management, emphasizing the importance of early viral infection diagnosis. In response, lateral flow assays (LFAs) have been successfully utilized in point-of-care (POC) testing, emerging as a viable alternative to more traditional diagnostic [...] Read more.
Controlling the progression of contagious diseases is crucial for public health management, emphasizing the importance of early viral infection diagnosis. In response, lateral flow assays (LFAs) have been successfully utilized in point-of-care (POC) testing, emerging as a viable alternative to more traditional diagnostic methods. Recent advancements in virus detection have primarily leveraged methods such as reverse transcription–polymerase chain reaction (RT-PCR), reverse transcription–loop-mediated isothermal amplification (RT-LAMP), and the enzyme-linked immunosorbent assay (ELISA). Despite their proven effectiveness, these conventional techniques are often expensive, require specialized expertise, and consume a significant amount of time. In contrast, LFAs utilize nanomaterial-based optical sensing technologies, including colorimetric, fluorescence, and surface-enhanced Raman scattering (SERS), offering quick, straightforward analyses with minimal training and infrastructure requirements for detecting viral proteins in biological samples. This review describes the composition and mechanism of and recent advancements in LFAs for viral protein detection, categorizing them into colorimetric, fluorescent, and SERS-based techniques. Despite significant progress, developing a simple, stable, highly sensitive, and selective LFA system remains a formidable challenge. Nevertheless, an advanced LFA system promises not only to enhance clinical diagnostics but also to extend its utility to environmental monitoring and beyond, demonstrating its potential to revolutionize both healthcare and environmental safety. Full article
(This article belongs to the Section Nano- and Micro-Technologies in Biosensors)
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15 pages, 2287 KiB  
Article
A CRISPR/Cas12a-Based System for Sensitive Detection of Antimicrobial-Resistant Genes in Carbapenem-Resistant Enterobacterales
by Jiyong Shin, Sei Rim Kim, Zifan Xie, Yong-Su Jin and Yi-Cheng Wang
Biosensors 2024, 14(4), 194; https://doi.org/10.3390/bios14040194 - 16 Apr 2024
Cited by 11 | Viewed by 3911
Abstract
Antimicrobial-resistant (AMR) bacteria pose a significant global health threat, and bacteria that produce New Delhi metallo-β-lactamase (NDM) are particularly concerning due to their resistance to most β-lactam antibiotics, including carbapenems. The emergence and spread of NDM-producing genes in food-producing animals highlight the need [...] Read more.
Antimicrobial-resistant (AMR) bacteria pose a significant global health threat, and bacteria that produce New Delhi metallo-β-lactamase (NDM) are particularly concerning due to their resistance to most β-lactam antibiotics, including carbapenems. The emergence and spread of NDM-producing genes in food-producing animals highlight the need for a fast and accurate method for detecting AMR bacteria. We therefore propose a PCR-coupled CRISPR/Cas12a-based fluorescence assay that can detect NDM-producing genes (blaNDM) in bacteria. Thanks to its designed gRNA, this CRISPR/Cas12a system was able to simultaneously cleave PCR amplicons and ssDNA-FQ reporters, generating fluorescence signals. Our method was found to be highly specific when tested against other foodborne pathogens that do not carry blaNDM and also demonstrated an excellent capability to distinguish single-nucleotide polymorphism. In the case of blaNDM-1 carrying E. coli, the assay performed exceptionally well, with a detection limit of 2.7 × 100 CFU/mL: 100 times better than conventional PCR with gel electrophoresis. Moreover, the developed assay detected AMR bacteria in food samples and exhibited enhanced performance compared to previously published real-time PCR assays. Thus, this novel PCR-coupled CRISPR/Cas12a-based fluorescence assay has considerable potential to improve current approaches to AMR gene detection and thereby contribute to mitigating the global threat of AMR. Full article
(This article belongs to the Special Issue CRISPR/Cas-Based Biosensing Systems: Development and Applications)
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24 pages, 1370 KiB  
Review
Electronic Tongues and Noses: A General Overview
by Diego Tibaduiza, Maribel Anaya, Johan Gómez, Juan Sarmiento, Maria Perez, Cristhian Lara, Johan Ruiz, Nicolas Osorio, Katerin Rodriguez, Isaac Hernandez and Carlos Sanchez
Biosensors 2024, 14(4), 190; https://doi.org/10.3390/bios14040190 - 13 Apr 2024
Cited by 14 | Viewed by 5139
Abstract
As technology advances, electronic tongues and noses are becoming increasingly important in various industries. These devices can accurately detect and identify different substances and gases based on their chemical composition. This can be incredibly useful in fields such as environmental monitoring and industrial [...] Read more.
As technology advances, electronic tongues and noses are becoming increasingly important in various industries. These devices can accurately detect and identify different substances and gases based on their chemical composition. This can be incredibly useful in fields such as environmental monitoring and industrial food applications, where the quality and safety of products or ecosystems should be ensured through a precise analysis. Traditionally, this task is performed by an expert panel or by using laboratory tests but sometimes becomes a bottleneck because of time and other human factors that can be solved with technologies such as the provided by electronic tongue and nose devices. Additionally, these devices can be used in medical diagnosis, quality monitoring, and even in the automotive industry to detect gas leaks. The possibilities are endless, and as these technologies continue to improve, they will undoubtedly play an increasingly important role in improving our lives and ensuring our safety. Because of the multiple applications and developments in this field in the last years, this work will present an overview of the electronic tongues and noses from the point of view of the approaches developed and the methodologies used in the data analysis and steps to this aim. In the same manner, this work shows some of the applications that can be found in the use of these devices and ends with some conclusions about the current state of these technologies. Full article
(This article belongs to the Special Issue Electrochemical (Bio-) Sensors in Biological Applications—2nd Edition)
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15 pages, 2644 KiB  
Article
A Novel Microfluidic Strategy for Efficient Exosome Separation via Thermally Oxidized Non-Uniform Deterministic Lateral Displacement (DLD) Arrays and Dielectrophoresis (DEP) Synergy
by Dayin Wang, Shijia Yang, Ning Wang, Han Guo, Shilun Feng, Yuan Luo and Jianlong Zhao
Biosensors 2024, 14(4), 174; https://doi.org/10.3390/bios14040174 - 4 Apr 2024
Cited by 8 | Viewed by 3392
Abstract
Exosomes, with diameters ranging from 30 to 150 nm, are saucer-shaped extracellular vesicles (EVs) secreted by various type of human cells. They are present in virtually all bodily fluids. Owing to their abundant nucleic acid and protein content, exosomes have emerged as promising [...] Read more.
Exosomes, with diameters ranging from 30 to 150 nm, are saucer-shaped extracellular vesicles (EVs) secreted by various type of human cells. They are present in virtually all bodily fluids. Owing to their abundant nucleic acid and protein content, exosomes have emerged as promising biomarkers for noninvasive molecular diagnostics. However, the need for exosome separation purification presents tremendous technical challenges due to their minuscule size. In recent years, microfluidic technology has garnered substantial interest as a promising alternative capable of excellent separation performance, reduced reagent consumption, and lower overall device and operation costs. In this context, we hereby propose a novel microfluidic strategy based on thermally oxidized deterministic lateral displacement (DLD) arrays with tapered shapes to enhance separation performance. We have achieved more than 90% purity in both polystyrene nanoparticle and exosome experiments. The use of thermal oxidation also significantly reduces fabrication complexity by avoiding the use of high-precision lithography. Furthermore, in a simulation model, we attempt to integrate the use of dielectrophoresis (DEP) to overcome the size-based nature of DLD and distinguish particles that are close in size but differ in biochemical compositions (e.g., lipoproteins, exomeres, retroviruses). We believe the proposed strategy heralds a versatile and innovative platform poised to enhance exosome analysis across a spectrum of biochemical applications. Full article
(This article belongs to the Special Issue Application of Microfluidics in Cell Manipulation and Biosensing)
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23 pages, 5990 KiB  
Review
Research Progress on the Application of Covalent Organic Framework Nanozymes in Analytical Chemistry
by Dongmei Yao, Ling Xia and Gongke Li
Biosensors 2024, 14(4), 163; https://doi.org/10.3390/bios14040163 - 29 Mar 2024
Cited by 6 | Viewed by 2736
Abstract
Covalent organic frameworks (COFs) are porous crystals that have high designability and great potential in designing, encapsulating, and immobilizing nanozymes. COF nanozymes have also attracted extensive attention in analyte sensing and detection because of their abundant active sites, high enzyme-carrying capacity, and significantly [...] Read more.
Covalent organic frameworks (COFs) are porous crystals that have high designability and great potential in designing, encapsulating, and immobilizing nanozymes. COF nanozymes have also attracted extensive attention in analyte sensing and detection because of their abundant active sites, high enzyme-carrying capacity, and significantly improved stability. In this paper, we classify COF nanozymes into three types and review their characteristics and advantages. Then, the synthesis methods of these COF nanozymes are introduced, and their performances are compared in a list. Finally, the applications of COF nanozymes in environmental analysis, food analysis, medicine analysis, disease diagnosis, and treatment are reviewed. Furthermore, we also discuss the application prospects of COF nanozymes and the challenges they face. Full article
(This article belongs to the Special Issue Enzyme Biosensors: Challenges and Future Perspectives)
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10 pages, 413 KiB  
Review
Standard Operating Procedure to Optimize Resazurin-Based Viability Assays
by Jessica Petiti, Laura Revel and Carla Divieto
Biosensors 2024, 14(4), 156; https://doi.org/10.3390/bios14040156 - 26 Mar 2024
Cited by 22 | Viewed by 9845
Abstract
The resazurin assay, also known as the Alamar Blue assay, stands as a cornerstone technique in cell biology, microbiology, and drug development. It assesses the viability of cells through the conversion of resazurin into highly fluorescent resorufin. The resulting fluorescence intensity provides a [...] Read more.
The resazurin assay, also known as the Alamar Blue assay, stands as a cornerstone technique in cell biology, microbiology, and drug development. It assesses the viability of cells through the conversion of resazurin into highly fluorescent resorufin. The resulting fluorescence intensity provides a reliable estimate of viable cell numbers. Cytotoxicity assays, such as the resazurin-based method, play a crucial role in the screening of potential drug candidates and in the assessment of pharmaceutical and chemical toxicity. In recent years, inconsistencies have arisen in pharmacogenomic studies, often due to poorly optimized laboratory protocols. These inconsistencies hinder progress in understanding how substances affect cell health, leading to unreliable findings. Thus, the need for standardized and rigorously optimized protocols is evident to ensure consistent and accurate results in cytotoxicity studies. This manuscript describes a standardized procedure for optimizing resazurin-based viability assays to improve the reliability of cytotoxicity data. This optimization approach focuses on critical experimental parameters and data quality, aiming to achieve a level of measurement imprecision of less than 20%. In conclusion, to address the critical issues of reproducibility and reliability, protocol standardization, such as the one described in this manuscript, can greatly enhance the credibility of cytotoxicity studies, ultimately advancing drug safety assessments. Full article
(This article belongs to the Section Biosensors and Healthcare)
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18 pages, 3412 KiB  
Article
Development of Highly Sensitive Fluorescent Sensors for Separation-Free Detection and Quantitation Systems of Pepsin Enzyme Applying a Structure-Guided Approach
by Aya M. Mostafa, Stephen J. Barton, Stephen P. Wren and James Barker
Biosensors 2024, 14(3), 151; https://doi.org/10.3390/bios14030151 - 20 Mar 2024
Cited by 3 | Viewed by 2137
Abstract
Two fluorescent molecularly imprinted polymers (MIPs) were developed for pepsin enzyme utilising fluorescein and rhodamine b. The main difference between both dyes is the presence of two (diethylamino) groups in the structure of rhodamine b. Consequently, we wanted to investigate the effect of [...] Read more.
Two fluorescent molecularly imprinted polymers (MIPs) were developed for pepsin enzyme utilising fluorescein and rhodamine b. The main difference between both dyes is the presence of two (diethylamino) groups in the structure of rhodamine b. Consequently, we wanted to investigate the effect of these functional groups on the selectivity and sensitivity of the resulting MIPs. Therefore, two silica-based MIPs for pepsin enzyme were developed using 3-aminopropyltriethoxysilane as a functional monomer and tetraethyl orthosilicate as a crosslinker to achieve a one-pot synthesis. Results of our study revealed that rhodamine b dyed MIPs (RMIPs) showed stronger binding, indicated by a higher binding capacity value of 256 mg g−1 compared to 217 mg g−1 for fluorescein dyed MIPs (FMIPs). Moreover, RMIPs showed superior sensitivity in the detection and quantitation of pepsin with a linear range from 0.28 to 42.85 µmol L−1 and a limit of detection (LOD) as low as 0.11 µmol L−1. In contrast, FMIPs covered a narrower range from 0.71 to 35.71 µmol L−1, and the LOD value reached 0.34 µmol L−1, which is three times less sensitive than RMIPs. Finally, the developed FMIPs and RMIPs were applied to a separation-free quantification system for pepsin in saliva samples without interference from any cross-reactors. Full article
(This article belongs to the Section Biosensors and Healthcare)
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24 pages, 1503 KiB  
Review
Continuous and Non-Invasive Lactate Monitoring Techniques in Critical Care Patients
by Jose-Luis Lafuente, Samuel González, Clara Aibar, Desirée Rivera, Eva Avilés and Juan-Jose Beunza
Biosensors 2024, 14(3), 148; https://doi.org/10.3390/bios14030148 - 18 Mar 2024
Cited by 8 | Viewed by 6759
Abstract
Lactate, once merely regarded as an indicator of tissue hypoxia and muscular fatigue, has now gained prominence as a pivotal biomarker across various medical disciplines. Recent research has unveiled its critical role as a high-value prognostic marker in critical care medicine. The current [...] Read more.
Lactate, once merely regarded as an indicator of tissue hypoxia and muscular fatigue, has now gained prominence as a pivotal biomarker across various medical disciplines. Recent research has unveiled its critical role as a high-value prognostic marker in critical care medicine. The current practice of lactate detection involves periodic blood sampling. This approach is invasive and confined to measurements at six-hour intervals, leading to resource expenditure, time consumption, and patient discomfort. This review addresses non-invasive sensors that enable continuous monitoring of lactate in critical care patients. After the introduction, it discusses the iontophoresis system, followed by a description of the structural materials that are universally employed to create an interface between the integumentary system and the sensor. Subsequently, each method is detailed according to its physical principle, outlining its advantages, limitations, and pertinent aspects. The study concludes with a discussion and conclusions, aiming at the design of an intelligent sensor (Internet of Medical Things or IoMT) to facilitate continuous lactate monitoring and enhance the clinical decision-making support system in critical care medicine. Full article
(This article belongs to the Section Biosensors and Healthcare)
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14 pages, 1102 KiB  
Article
Towards a Self-Powered Amperometric Glucose Biosensor Based on a Single-Enzyme Biofuel Cell
by Asta Kausaite-Minkstimiene, Algimantas Kaminskas, Galina Gayda and Almira Ramanaviciene
Biosensors 2024, 14(3), 138; https://doi.org/10.3390/bios14030138 - 8 Mar 2024
Cited by 9 | Viewed by 3518
Abstract
This paper describes the study of an amperometric glucose biosensor based on an enzymatic biofuel cell consisting of a bioanode and a biocathode modified with the same enzyme—glucose oxidase (GOx). A graphite rod electrode (GRE) was electrochemically modified with a layer of Prussian [...] Read more.
This paper describes the study of an amperometric glucose biosensor based on an enzymatic biofuel cell consisting of a bioanode and a biocathode modified with the same enzyme—glucose oxidase (GOx). A graphite rod electrode (GRE) was electrochemically modified with a layer of Prussian blue (PB) nanoparticles embedded in a poly(pyrrole-2-carboxylic acid) (PPCA) shell, and an additional layer of PPCA and was used as the cathode. A GRE modified with a nanocomposite composed of poly(1,10-phenanthroline-5,6-dione) (PPD) and gold nanoparticles (AuNPs) entrapped in a PPCA shell was used as an anode. Both electrodes were modified with GOx by covalently bonding the enzyme to the carboxyl groups of PPCA. The developed biosensor exhibited a wide linear range of 0.15–124.00 mM with an R2 of 0.9998 and a sensitivity of 0.16 μA/mM. The limit of detection (LOD) and quantification (LOQ) were found to be 0.07 and 0.23 mM, respectively. The biosensor demonstrated exceptional selectivity to glucose and operational stability throughout 35 days, as well as good reproducibility, repeatability, and anti-interference ability towards common interfering substances. The studies on human serum demonstrate the ability of the newly designed biosensor to determine glucose in complex real samples at clinically relevant concentrations. Full article
(This article belongs to the Special Issue Recent Advances in Glucose Biosensors)
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32 pages, 6840 KiB  
Review
Advancements in Brain Research: The In Vivo/In Vitro Electrochemical Detection of Neurochemicals
by Xiaoxuan Xu, Yimei Zuo, Shu Chen, Amir Hatami and Hui Gu
Biosensors 2024, 14(3), 125; https://doi.org/10.3390/bios14030125 - 26 Feb 2024
Cited by 9 | Viewed by 4985
Abstract
Neurochemicals, crucial for nervous system function, influence vital bodily processes and their fluctuations are linked to neurodegenerative diseases and mental health conditions. Monitoring these compounds is pivotal, yet the intricate nature of the central nervous system poses challenges. Researchers have devised methods, notably [...] Read more.
Neurochemicals, crucial for nervous system function, influence vital bodily processes and their fluctuations are linked to neurodegenerative diseases and mental health conditions. Monitoring these compounds is pivotal, yet the intricate nature of the central nervous system poses challenges. Researchers have devised methods, notably electrochemical sensing with micro-nanoscale electrodes, offering high-resolution monitoring despite low concentrations and rapid changes. Implantable sensors enable precise detection in brain tissues with minimal damage, while microdialysis-coupled platforms allow in vivo sampling and subsequent in vitro analysis, addressing the selectivity issues seen in other methods. While lacking temporal resolution, techniques like HPLC and CE complement electrochemical sensing’s selectivity, particularly for structurally similar neurochemicals. This review covers essential neurochemicals and explores miniaturized electrochemical sensors for brain analysis, emphasizing microdialysis integration. It discusses the pros and cons of these techniques, forecasting electrochemical sensing’s future in neuroscience research. Overall, this comprehensive review outlines the evolution, strengths, and potential applications of electrochemical sensing in the study of neurochemicals, offering insights into future advancements in the field. Full article
(This article belongs to the Special Issue Trends in Development of Biosensors for Disease Diagnosis, Treatment and Management—2nd Edition)
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29 pages, 1939 KiB  
Review
On-Site Bioaerosol Sampling and Airborne Microorganism Detection Technologies
by Afagh Rastmanesh, Jayanta S. Boruah, Min-Seok Lee and Seungkyung Park
Biosensors 2024, 14(3), 122; https://doi.org/10.3390/bios14030122 - 24 Feb 2024
Cited by 12 | Viewed by 8508
Abstract
Bioaerosols are small airborne particles composed of microbiological fragments, including bacteria, viruses, fungi, pollens, and/or by-products of cells, which may be viable or non-viable wherever applicable. Exposure to these agents can cause a variety of health issues, such as allergic and infectious diseases, [...] Read more.
Bioaerosols are small airborne particles composed of microbiological fragments, including bacteria, viruses, fungi, pollens, and/or by-products of cells, which may be viable or non-viable wherever applicable. Exposure to these agents can cause a variety of health issues, such as allergic and infectious diseases, neurological disorders, and cancer. Therefore, detecting and identifying bioaerosols is crucial, and bioaerosol sampling is a key step in any bioaerosol investigation. This review provides an overview of the current bioaerosol sampling methods, both passive and active, as well as their applications and limitations for rapid on-site monitoring. The challenges and trends for detecting airborne microorganisms using molecular and immunological methods are also discussed, along with a summary and outlook for the development of prompt monitoring technologies. Full article
(This article belongs to the Special Issue Point of Care Diagnostics for Infectious Disease)
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13 pages, 1476 KiB  
Article
Switching Separation Migration Order by Switching Electrokinetic Regime in Electrokinetic Microsystems
by Alaleh Vaghef-Koodehi and Blanca H. Lapizco-Encinas
Biosensors 2024, 14(3), 119; https://doi.org/10.3390/bios14030119 - 22 Feb 2024
Cited by 4 | Viewed by 1615
Abstract
Analyte migration order is a major aspect in all migration-based analytical separations methods. Presented here is the manipulation of the migration order of microparticles in an insulator-based electrokinetic separation. Three distinct particle mixtures were studied: a binary mixture of particles with similar electrical [...] Read more.
Analyte migration order is a major aspect in all migration-based analytical separations methods. Presented here is the manipulation of the migration order of microparticles in an insulator-based electrokinetic separation. Three distinct particle mixtures were studied: a binary mixture of particles with similar electrical charge and different sizes, and two tertiary mixtures of particles of distinct sizes. Each one of the particle mixtures was separated twice, the first separation was performed under low voltage (linear electrokinetic regime) and the second separation was performed under high voltage (nonlinear electrokinetic regime). Linear electrophoresis, which discriminates particles by charge, is the dominant electrokinetic effect in the linear regime; while nonlinear electrophoresis, which discriminates particles by size and shape, is the dominant electrokinetic effect in the nonlinear regime. The separation results obtained with the three particle mixtures illustrated that particle elution order can be changed by switching from the linear electrokinetic regime to the nonlinear electrokinetic regime. Also, in all cases, better separation performances in terms of separation resolution (Rs) were obtained by employing the nonlinear electrokinetic regime allowing nonlinear electrophoresis to be the discriminatory electrokinetic mechanism. These findings could be applied to analyze complex samples containing bioparticles of interest within the micron size range. This is the first report where particle elution order is altered in an iEK system. Full article
(This article belongs to the Special Issue Advanced Microfluidic Devices and Lab-on-Chip (Bio)sensors)
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13 pages, 2749 KiB  
Article
Real-Time On-Site Monitoring of Viruses in Wastewater Using Nanotrap® Particles and RICCA Technologies
by Vishnu Sharma, Hitomi Takamura, Manish Biyani and Ryo Honda
Biosensors 2024, 14(3), 115; https://doi.org/10.3390/bios14030115 - 21 Feb 2024
Cited by 5 | Viewed by 2650
Abstract
Wastewater-based epidemiology (WBE) is an effective and efficient tool for the early detection of infectious disease outbreaks in a community. However, currently available methods are laborious, costly, and time-consuming due to the low concentration of viruses and the presence of matrix chemicals in [...] Read more.
Wastewater-based epidemiology (WBE) is an effective and efficient tool for the early detection of infectious disease outbreaks in a community. However, currently available methods are laborious, costly, and time-consuming due to the low concentration of viruses and the presence of matrix chemicals in wastewater that may interfere with molecular analyses. In the present study, we designed a highly sensitive “Quick Poop (wastewater with fecal waste) Sensor” (termed, QPsor) using a joint approach of Nanotrap microbiome particles and RICCA (RNA Isothermal Co-Assisted and Coupled Amplification). Using QPsor, the WBE study showed a strong correlation with standard PEG concentrations and the qPCR technique. Using a closed format for a paper-based lateral flow assay, we were able to demonstrate the potential of our assay as a real-time, point-of-care test by detecting the heat-inactivated SARS-CoV-2 virus in wastewater at concentrations of 100 copies/mL and within one hour. As a proof-of-concept demonstration, we analyzed the presence of viral RNA of the SARS-CoV-2 virus and PMMoV in raw wastewater samples from wastewater treatment plants on-site and within 60 min. The results show that the QPsor method can be an effective tool for disease outbreak detection by combining an AI-enabled case detection model with real-time on-site viral RNA extraction and amplification, especially in the absence of intensive clinical laboratory facilities. The lab-free, lab-quality test capabilities of QPsor for viral prevalence and transmission in the community can contribute to the efficient management of pandemic situations. Full article
(This article belongs to the Special Issue Microbial Biosensor: From Design to Applications)
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18 pages, 3848 KiB  
Article
Design of a Porous Silicon Biosensor: Characterization, Modeling, and Application to the Indirect Detection of Bacteria
by Roselien Vercauteren, Clémentine Gevers, Jacques Mahillon and Laurent A. Francis
Biosensors 2024, 14(2), 104; https://doi.org/10.3390/bios14020104 - 17 Feb 2024
Cited by 5 | Viewed by 2241
Abstract
The design of a porous silicon (PSi) biosensor is not often documented, but is of the upmost importance to optimize its performance. In this work, the motivation behind the design choices of a PSi-based optical biosensor for the indirect detection of bacteria via [...] Read more.
The design of a porous silicon (PSi) biosensor is not often documented, but is of the upmost importance to optimize its performance. In this work, the motivation behind the design choices of a PSi-based optical biosensor for the indirect detection of bacteria via their lysis is detailed. The transducer, based on a PSi membrane, was characterized and models were built to simulate the analyte diffusion, depending on the porous nanostructures, and to optimize the optical properties. Once all performances and properties were analyzed and optimized, a theoretical response was calculated. The theoretical limit of detection was computed as 104 CFU/mL, based on the noise levels of the optical setup. The experimental response was measured using 106 CFU/mL of Bacillus cereus as model strain, lysed by bacteriophage-coded endolysins PlyB221. The obtained signal matched the expected response, demonstrating the validity of our design and models. Full article
(This article belongs to the Special Issue MEMS Based Biosensors and Its Applications)
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20 pages, 22209 KiB  
Review
Advances in Cancer Research: Current and Future Diagnostic and Therapeutic Strategies
by Xiaohui Liu, Hui Jiang and Xuemei Wang
Biosensors 2024, 14(2), 100; https://doi.org/10.3390/bios14020100 - 16 Feb 2024
Cited by 14 | Viewed by 6611
Abstract
Cancers of unknown primary (CUP) exhibit significant cellular heterogeneity and malignancy, which poses significant challenges for diagnosis and treatment. Recent years have seen deeper insights into the imaging, pathology, and genetic characteristics of CUP, driven by interdisciplinary collaboration and the evolution of diagnostic [...] Read more.
Cancers of unknown primary (CUP) exhibit significant cellular heterogeneity and malignancy, which poses significant challenges for diagnosis and treatment. Recent years have seen deeper insights into the imaging, pathology, and genetic characteristics of CUP, driven by interdisciplinary collaboration and the evolution of diagnostic and therapeutic strategies. However, due to their insidious onset, lack of evidence-based medicine, and limited clinical understanding, diagnosing and treating CUP remain a significant challenge. To inspire more creative and fantastic research, herein, we report and highlight recent advances in the diagnosis and therapeutic strategies of CUP. Specifically, we discuss advanced diagnostic technologies, including 12-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography (18F-FDG PET/CT) or 68Ga-FAPI (fibroblast activation protein inhibitor) PET/CT, liquid biopsy, molecular diagnostics, self-assembling nanotechnology, and artificial intelligence (AI). In particular, the discussion will extend to the effective treatment techniques currently available, such as targeted therapies, immunotherapies, and bio-nanotechnology-based therapeutics. Finally, a novel perspective on the challenges and directions for future CUP diagnostic and therapeutic strategies is discussed. Full article
(This article belongs to the Special Issue Trends and Perspective of Advanced Nanotechnology for Bio-Sensing, Imaging and Cancer Therapy)
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13 pages, 1496 KiB  
Article
Development of Taste Sensor with Lipid/Polymer Membranes for Detection of Umami Substances Using Surface Modification
by Wenhao Yuan, Zeyu Zhao, Shunsuke Kimura and Kiyoshi Toko
Biosensors 2024, 14(2), 95; https://doi.org/10.3390/bios14020095 - 11 Feb 2024
Cited by 3 | Viewed by 2737
Abstract
A taste sensor employs various lipid/polymer membranes with specific physicochemical properties for taste classification and evaluation. However, phosphoric acid di(2-ethylhexyl) ester (PAEE), employed as one of the lipids for the taste sensors, exhibits insufficient selectivity for umami substances. The pH of sample solutions [...] Read more.
A taste sensor employs various lipid/polymer membranes with specific physicochemical properties for taste classification and evaluation. However, phosphoric acid di(2-ethylhexyl) ester (PAEE), employed as one of the lipids for the taste sensors, exhibits insufficient selectivity for umami substances. The pH of sample solutions impacts the dissociation of lipids to influence the membrane potential, and the response to astringent substances makes accurate measurement of umami taste difficult. This study aims to develop a novel taste sensor for detecting umami substances like monosodium L-glutamate (MSG) through surface modification, i.e., a methodology previously applied to taste sensors for non-charged bitter substance measurement. Four kinds of modifiers were tested as membrane-modifying materials. By comparing the results obtained from these modifiers, the modifier structure suitable for measuring umami substances was identified. The findings revealed that the presence of carboxyl groups at para-position of the benzene ring, as well as intramolecular H-bonds between the carboxyl group and hydroxyl group, significantly affect the effectiveness of a modifier in the umami substance measurement. The taste sensor treated with this type of modifier showed excellent selectivity for umami substances. Full article
(This article belongs to the Special Issue Applications of Advanced Electrochemical (Bio)sensors in Environment, Food, and Medicine)
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50 pages, 3619 KiB  
Review
Advances in Respiratory Monitoring: A Comprehensive Review of Wearable and Remote Technologies
by Diana Vitazkova, Erik Foltan, Helena Kosnacova, Michal Micjan, Martin Donoval, Anton Kuzma, Martin Kopani and Erik Vavrinsky
Biosensors 2024, 14(2), 90; https://doi.org/10.3390/bios14020090 - 6 Feb 2024
Cited by 47 | Viewed by 19972
Abstract
This article explores the importance of wearable and remote technologies in healthcare. The focus highlights its potential in continuous monitoring, examines the specificity of the issue, and offers a view of proactive healthcare. Our research describes a wide range of device types and [...] Read more.
This article explores the importance of wearable and remote technologies in healthcare. The focus highlights its potential in continuous monitoring, examines the specificity of the issue, and offers a view of proactive healthcare. Our research describes a wide range of device types and scientific methodologies, starting from traditional chest belts to their modern alternatives and cutting-edge bioamplifiers that distinguish breathing from chest impedance variations. We also investigated innovative technologies such as the monitoring of thorax micromovements based on the principles of seismocardiography, ballistocardiography, remote camera recordings, deployment of integrated optical fibers, or extraction of respiration from cardiovascular variables. Our review is extended to include acoustic methods and breath and blood gas analysis, providing a comprehensive overview of different approaches to respiratory monitoring. The topic of monitoring respiration with wearable and remote electronics is currently the center of attention of researchers, which is also reflected by the growing number of publications. In our manuscript, we offer an overview of the most interesting ones. Full article
(This article belongs to the Special Issue Wearable Biofluid Monitoring Sensors and Devices)
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27 pages, 8123 KiB  
Review
Electrochemically Synthesized MIP Sensors: Applications in Healthcare Diagnostics
by Akinrinade George Ayankojo, Jekaterina Reut and Vitali Syritski
Biosensors 2024, 14(2), 71; https://doi.org/10.3390/bios14020071 - 30 Jan 2024
Cited by 21 | Viewed by 3965
Abstract
Early-stage detection and diagnosis of diseases is essential to the prompt commencement of treatment regimens, curbing the spread of the disease, and improving human health. Thus, the accurate detection of disease biomarkers through the development of robust, sensitive, and selective diagnostic tools has [...] Read more.
Early-stage detection and diagnosis of diseases is essential to the prompt commencement of treatment regimens, curbing the spread of the disease, and improving human health. Thus, the accurate detection of disease biomarkers through the development of robust, sensitive, and selective diagnostic tools has remained cutting-edge scientific research for decades. Due to their merits of being selective, stable, simple, and having a low preparation cost, molecularly imprinted polymers (MIPs) are increasingly becoming artificial substitutes for natural receptors in the design of state-of-the-art sensing devices. While there are different MIP preparation approaches, electrochemical synthesis presents a unique and outstanding method for chemical sensing applications, allowing the direct formation of the polymer on the transducer as well as simplicity in tuning the film properties, thus accelerating the trend in the design of commercial MIP-based sensors. This review evaluates recent achievements in the applications of electrosynthesized MIP sensors for clinical analysis of disease biomarkers, identifying major trends and highlighting interesting perspectives on the realization of commercial MIP-endowed testing devices for rapid determination of prevailing diseases. Full article
(This article belongs to the Special Issue Electrochemical (Bio-) Sensors in Biological Applications—2nd Edition)
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19 pages, 4969 KiB  
Review
Advances in Engineered Nano-Biosensors for Bacteria Diagnosis and Multidrug Resistance Inhibition
by Qingxiu Xia, Hui Jiang, Xiaohui Liu, Lihong Yin and Xuemei Wang
Biosensors 2024, 14(2), 59; https://doi.org/10.3390/bios14020059 - 23 Jan 2024
Cited by 4 | Viewed by 4335
Abstract
Bacterial infections continue to pose a significant global health challenge, with the emergence of multidrug-resistant (MDR) bacteria and biofilms further complicating treatment options. The rise of pan-resistant bacteria, coupled with the slow development of new antibiotics, highlights the urgent need for new therapeutic [...] Read more.
Bacterial infections continue to pose a significant global health challenge, with the emergence of multidrug-resistant (MDR) bacteria and biofilms further complicating treatment options. The rise of pan-resistant bacteria, coupled with the slow development of new antibiotics, highlights the urgent need for new therapeutic strategies. Nanotechnology-based biosensors offer fast, specific, sensitive, and selective methods for detecting and treating bacteria; hence, it is a promising approach for the diagnosis and treatment of MDR bacteria. Through mechanisms, such as destructive bacterial cell membranes, suppression of efflux pumps, and generation of reactive oxygen species, nanotechnology effectively combats bacterial resistance and biofilms. Nano-biosensors and related technology have demonstrated their importance in bacteria diagnosis and treatment, providing innovative ideas for MDR inhibition. This review focuses on multiple nanotechnology approaches in targeting MDR bacteria and eliminating antimicrobial biofilms, highlighting nano-biosensors via photodynamics-based biosensors, eletrochemistry biosensors, acoustic-dynamics sensors, and so on. Furthermore, the major challenges, opportunities of multi-physical-field biometrics-based biosensors, and relevant nanotechnology in MDR bacterial theranostics are also discussed. Overall, this review provides insights and scientific references to harness the comprehensive and diverse capabilities of nano-biosensors for precise bacteria theranostics and MDR inhibition. Full article
(This article belongs to the Special Issue Biosensor Nanoengineering: Design, Operation and Implementation)
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10 pages, 1525 KiB  
Article
Aptamer-Based Switching System for Communication of Non-Interacting Proteins
by Younghyeon Kim, Daehan Nam, Eun Sung Lee, Seokjoon Kim, Byung Seok Cha and Ki Soo Park
Biosensors 2024, 14(1), 47; https://doi.org/10.3390/bios14010047 - 16 Jan 2024
Cited by 3 | Viewed by 2682
Abstract
Biological macromolecules, such as DNA, RNA, and proteins in living organisms, form an intricate network that plays a key role in many biological processes. Many attempts have been made to build new networks by connecting non-communicable proteins with network mediators, especially using antibodies. [...] Read more.
Biological macromolecules, such as DNA, RNA, and proteins in living organisms, form an intricate network that plays a key role in many biological processes. Many attempts have been made to build new networks by connecting non-communicable proteins with network mediators, especially using antibodies. In this study, we devised an aptamer-based switching system that enables communication between non-interacting proteins. As a proof of concept, two proteins, Cas13a and T7 RNA polymerase (T7 RNAP), were rationally connected using an aptamer that specifically binds to T7 RNAP. The proposed switching system can be modulated in both signal-on and signal-off manners and its responsiveness to the target activator can be controlled by adjusting the reaction time. This study paves the way for the expansion of biological networks by mediating interactions between proteins using aptamers. Full article
(This article belongs to the Special Issue CRISPR/Cas-Based Biosensing Systems: Development and Applications)
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12 pages, 1913 KiB  
Article
ZIF-67 Anchored on MoS2/rGO Heterostructure for Non-Enzymatic and Visible-Light-Sensitive Photoelectrochemical Biosensing
by Qiaolin Fan, Xiao Li, Hui Dong, Zhonghua Ni and Tao Hu
Biosensors 2024, 14(1), 38; https://doi.org/10.3390/bios14010038 - 12 Jan 2024
Cited by 7 | Viewed by 2705
Abstract
Graphene and graphene-like two-dimensional layered nanomaterials-based photoelectrochemical (PEC) biosensors have recently grown rapidly in popularity thanks to their advantages of high sensitivity and low background signal, which have attracted tremendous attention in ultrahigh sensitive small molecule detection. This work proposes a non-enzymatic and [...] Read more.
Graphene and graphene-like two-dimensional layered nanomaterials-based photoelectrochemical (PEC) biosensors have recently grown rapidly in popularity thanks to their advantages of high sensitivity and low background signal, which have attracted tremendous attention in ultrahigh sensitive small molecule detection. This work proposes a non-enzymatic and visible-light-sensitive PEC biosensing platform based on ZIF-67@MoS2/rGO composite which is synthesized through a facile and one-step microwave-assisted hydrothermal method. The combination of MoS2 and rGO could construct van der Waals heterostructures, which not only act as visible-light-active nanomaterials, but facilitate charge carriers transfer between the photoelectrode and glassy carbon electrode (GCE). ZIF-67 anchored on MoS2/rGO heterostructures provides large specific surface areas and a high proportion of catalytic sites, which cooperate with MoS2 nanosheets, realizing rapid and efficient enzyme-free electrocatalytic oxidation of glucose. The ZIF-67@MoS2/rGO-modified GCE can realize the rapid and sensitive detection of glucose at low detection voltage, which exhibits a high sensitivity of 12.62 μAmM−1cm−2. Finally, the ZIF-67@MoS2/rGO PEC biosensor is developed by integrating the ZIF-67@MoS2/rGO with a screen-printed electrode (SPE), which exhibits a high sensitivity of 3.479 μAmM−1cm−2 and a low detection limit of 1.39 μM. The biosensor’s selectivity, stability, and repeatability are systematically investigated, and its practicability is evaluated by detecting clinical serum samples. Full article
(This article belongs to the Special Issue Recent Advances in Hydrogels-Based Biosensors for Point-of-Care Testing)
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15 pages, 2700 KiB  
Review
Advances in the Application of Transition-Metal Composite Nanozymes in the Field of Biomedicine
by Huixin Wang, Chunfang Cheng, Jingyu Zhao, Fangqin Han, Guanhui Zhao, Yong Zhang and Yaoguang Wang
Biosensors 2024, 14(1), 40; https://doi.org/10.3390/bios14010040 - 12 Jan 2024
Cited by 16 | Viewed by 3001
Abstract
Due to the limitation that natural peroxidase enzymes can only function in relatively mild environments, nanozymes have expanded the application of enzymology in the biological field by dint of their ability to maintain catalytic oxidative activity in relatively harsh environments. At the same [...] Read more.
Due to the limitation that natural peroxidase enzymes can only function in relatively mild environments, nanozymes have expanded the application of enzymology in the biological field by dint of their ability to maintain catalytic oxidative activity in relatively harsh environments. At the same time, the development of new and highly efficient composite nanozymes has been a challenge due to the limitations of monometallic particles in applications and the inherently poor enzyme-mimetic activity of composite nanozymes. The inherent enzyme-mimicking activity is due to Au, Ag, and Pt, along with other transition metals. Moreover, the nanomaterials exhibit excellent enzyme-mimicking activity when composited with other materials. Therefore, this paper focuses on composite nanozymes with simulated peroxidase activity that have been prepared using noble metals such as Au, Ag, and Pt and other transition metal nanoparticles in recent years. Their simulated enzymatic activity is utilized for biomedical applications such as glucose detection, cancer cell detection and tumor treatment, and antibacterial applications. Full article
(This article belongs to the Section Nano- and Micro-Technologies in Biosensors)
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13 pages, 2317 KiB  
Article
Rapid and Easy Detection of Microcystin-LR Using a Bioactivated Multi-Walled Carbon Nanotube-Based Field-Effect Transistor Sensor
by Myeongsoon Lee, Seong H. Kim, Don Kim and Hak Jun Kim
Biosensors 2024, 14(1), 37; https://doi.org/10.3390/bios14010037 - 11 Jan 2024
Cited by 3 | Viewed by 2459
Abstract
In this study, we developed a multi-walled carbon nanotube (MWCNT)-based field-effect transistor (MWCNT-FET) sensor with high sensitivity and selectivity for microcystin-LR (MC-LR). Carboxylated MWCNTs were activated with an MC-LR-targeting aptamer (MCTA). Subsequently the bioactivated MWCNTs were immobilized between interdigitated drain (D) and source [...] Read more.
In this study, we developed a multi-walled carbon nanotube (MWCNT)-based field-effect transistor (MWCNT-FET) sensor with high sensitivity and selectivity for microcystin-LR (MC-LR). Carboxylated MWCNTs were activated with an MC-LR-targeting aptamer (MCTA). Subsequently the bioactivated MWCNTs were immobilized between interdigitated drain (D) and source (S) electrodes through self-assembly. The top-gated MWCNT-FET sensor was configured by dropping the sample solution onto the D and S electrodes and immersing a Ag/AgCl electrode in the sample solution as a gate (G) electrode. We believe that the FET sensor’s conduction path arises from the interplay between the MCTAs, with the applied gate potential modulating this path. Using standard instruments and a personal computer, the sensor’s response was detected in real-time within a 10 min time frame. This label-free FET sensor demonstrated an impressive detection capability for MC-LR in the concentration range of 0.1–0.5 ng/mL, exhibiting a lower detection limit of 0.11 ng/mL. Additionally, the MWCNT-FET sensor displayed consistent reproducibility, a robust selectivity for MC-LR over its congeners, and minimal matrix interferences. Given these attributes, this easily mass-producible FET sensor is a promising tool for rapid, straightforward, and sensitive MC-LR detection in freshwater environments. Full article
(This article belongs to the Special Issue Field-Effect Transistor-Based Biosensors)
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18 pages, 7260 KiB  
Article
System of Implantable Electrodes for Neural Signal Acquisition and Stimulation for Wirelessly Connected Forearm Prosthesis
by Octavian Narcis Ionescu, Eduard Franti, Vlad Carbunaru, Carmen Moldovan, Silviu Dinulescu, Marian Ion, David Catalin Dragomir, Carmen Marinela Mihailescu, Ioan Lascar, Ana Maria Oproiu, Tiberiu Paul Neagu, Ruxandra Costea, Monica Dascalu, Mihai Daniel Teleanu, Gabriela Ionescu and Raluca Teleanu
Biosensors 2024, 14(1), 31; https://doi.org/10.3390/bios14010031 - 9 Jan 2024
Cited by 2 | Viewed by 2978
Abstract
There is great interest in the development of prosthetic limbs capable of complex activities that are wirelessly connected to the patient’s neural system. Although some progress has been achieved in this area, one of the main problems encountered is the selective acquisition of [...] Read more.
There is great interest in the development of prosthetic limbs capable of complex activities that are wirelessly connected to the patient’s neural system. Although some progress has been achieved in this area, one of the main problems encountered is the selective acquisition of nerve impulses and the closing of the automation loop through the selective stimulation of the sensitive branches of the patient. Large-scale research and development have achieved so-called “cuff electrodes”; however, they present a big disadvantage: they are not selective. In this article, we present the progress made in the development of an implantable system of plug neural microelectrodes that relate to the biological nerve tissue and can be used for the selective acquisition of neuronal signals and for the stimulation of specific nerve fascicles. The developed plug electrodes are also advantageous due to their small thickness, as they do not trigger nerve inflammation. In addition, the results of the conducted tests on a sous scrofa subject are presented. Full article
(This article belongs to the Special Issue Recent Advances in Microneedle Array Electrodes in Biomedicine)
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38 pages, 6209 KiB  
Review
Advances in Non-Electrochemical Sensing of Human Sweat Biomarkers: From Sweat Sampling to Signal Reading
by Mingpeng Yang, Nan Sun, Xiaochen Lai, Xingqiang Zhao and Wangping Zhou
Biosensors 2024, 14(1), 17; https://doi.org/10.3390/bios14010017 - 28 Dec 2023
Cited by 5 | Viewed by 4119
Abstract
Sweat, commonly referred to as the ultrafiltrate of blood plasma, is an essential physiological fluid in the human body. It contains a wide range of metabolites, electrolytes, and other biologically significant markers that are closely linked to human health. Compared to other bodily [...] Read more.
Sweat, commonly referred to as the ultrafiltrate of blood plasma, is an essential physiological fluid in the human body. It contains a wide range of metabolites, electrolytes, and other biologically significant markers that are closely linked to human health. Compared to other bodily fluids, such as blood, sweat offers distinct advantages in terms of ease of collection and non-invasive detection. In recent years, considerable attention has been focused on wearable sweat sensors due to their potential for continuous monitoring of biomarkers. Electrochemical methods have been extensively used for in situ sweat biomarker analysis, as thoroughly reviewed by various researchers. This comprehensive review aims to provide an overview of recent advances in non-electrochemical methods for analyzing sweat, including colorimetric methods, fluorescence techniques, surface-enhanced Raman spectroscopy, and more. The review covers multiple aspects of non-electrochemical sweat analysis, encompassing sweat sampling methodologies, detection techniques, signal processing, and diverse applications. Furthermore, it highlights the current bottlenecks and challenges faced by non-electrochemical sensors, such as limitations and interference issues. Finally, the review concludes by offering insights into the prospects for non-electrochemical sensing technologies. By providing a valuable reference and inspiring researchers engaged in the field of sweat sensor development, this paper aspires to foster the creation of innovative and practical advancements in this domain. Full article
(This article belongs to the Special Issue Wearable Bio/Chemical Sensors for Healthcare Monitoring)
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