Biosensors

18 pages, 5794 KiB

Open AccessArticle

Competitive Electrochemical Apta-Assay Based on cDNA–Ferrocene and MXenes for Staphylococcus aureus Surface Protein A Detection

by Ana-Maria Tătaru, Alexandra Canciu, Alin-Dan Chiorean, Ioana Runcan, Alexandru Radu, Mădălina Adriana Bordea, Maria Suciu, Mihaela Tertiș, Andreea Cernat and Cecilia Cristea

Biosensors 2024, 14(12), 636; https://doi.org/10.3390/bios14120636 (registering DOI) - 21 Dec 2024

Abstract

Staphylococcus aureus (S. aureus) represents one of the most frequent worldwide causes of morbidity and mortality due to an infectious agent. It is a part of the infamous ESKAPE group, which is highly connected with increased rates of healthcare-associated infections and [...] Read more.

Staphylococcus aureus (S. aureus) represents one of the most frequent worldwide causes of morbidity and mortality due to an infectious agent. It is a part of the infamous ESKAPE group, which is highly connected with increased rates of healthcare-associated infections and antimicrobial resistance. S. aureus can cause a large variety of diseases. Protein A (PrA) is a cell-wall-anchored protein of S. aureus with multiple key roles in colonization and pathogenesis and can be considered as a marker of S. aureus. The development of aptasensors, having an aptamer as a specific biorecognition element, increases selectivity, especially when working with complex matrices. The association with state-of-the-art materials, such as MXenes, can further improve the analytical performance. A competitive aptasensor configuration based on a ferrocene (Fc)-labeled cDNA hybridized (cDNA-Fc S13) on a specific aptamer (APT) for PrA in the presence of MXene nanosheets was designed for the indirect detection of S. aureus. The aptasensor displayed a linear range of 10–125 nM, an LOD of 3.33 nM, and a response time under 40 min. This configuration has been tested in real samples from volunteers diagnosed with S. aureus infections with satisfactory results, enabling the perspective to develop decentralized devices for the rapid detection of bacterial strains. Full article

(This article belongs to the Special Issue Feature Paper in Biosensor and Bioelectronic Devices 2024)

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14 pages, 2308 KiB

Open AccessArticle

Role of en-APTAS Membranes in Enhancing the NO₂ Gas-Sensing Characteristics of Carbon Nanotube/ZnO-Based Memristor Gas Sensors

by Ibtisam Ahmad, Mohsin Ali and Hee-Dong Kim

Biosensors 2024, 14(12), 635; https://doi.org/10.3390/bios14120635 (registering DOI) - 20 Dec 2024

Abstract

NO₂ is a toxic gas that can damage the lungs with prolonged exposure and contribute to health conditions, such as asthma in children. Detecting NO₂ is therefore crucial for maintaining a healthy environment. Carbon nanotubes (CNTs) are promising materials for NO [...] Read more.

NO₂ is a toxic gas that can damage the lungs with prolonged exposure and contribute to health conditions, such as asthma in children. Detecting NO₂ is therefore crucial for maintaining a healthy environment. Carbon nanotubes (CNTs) are promising materials for NO₂ gas sensors due to their excellent electronic properties and high adsorption energy for NO₂ molecules. However, conventional CNT-based sensors face challenges, including low responses at room temperature (RT) and slow recovery times. This study introduces a memristor-based NO₂ gas sensor comprising CNT/ZnO/ITO decorated with an N-[3-(trimethoxysilyl)propyl] ethylene diamine (en-APTAS) membrane to enhance room-temperature-sensing performance. The amine groups in the en-APTAS membrane increase adsorption sites and boost charge transfer interactions between NO₂ and the CNT surface. This modification improves the sensor’s response by 60% at 20 ppm compared to the undecorated counterpart. However, the high adsorption energy of NO₂ slows the recovery process. To overcome this, a pulse-recovery method was implemented, applying a −2.5 V pulse with a 1 ms width, enabling the sensor to return to its baseline within 1 ms. These findings highlight the effectiveness of en-APTAS decoration and pulse-recovery techniques in improving the sensitivity, response, and recovery of CNT-based gas sensors. Full article

(This article belongs to the Special Issue Bioelectronics and Biosensors Using Novel Metal-Oxide and Semiconductor Materials)

24 pages, 3293 KiB

Open AccessArticle

Exploring the Interaction of Biotinylated FcGamma RI and IgG1 Monoclonal Antibodies on Streptavidin-Coated Plasmonic Sensor Chips for Label-Free VEGF Detection

by Soodeh Salimi Khaligh, Fahd Khalid-Salako, Hasan Kurt and Meral Yüce

Biosensors 2024, 14(12), 634; https://doi.org/10.3390/bios14120634 - 20 Dec 2024

Abstract

Vascular endothelial growth factor (VEGF) is a critical angiogenesis biomarker associated with various pathological conditions, including cancer. This study leverages pre-biotinylated FcγRI interactions with IgG1-type monoclonal antibodies to develop a sensitive VEGF detection method. Utilizing surface plasmon resonance (SPR) technology, we characterized the [...] Read more.

Vascular endothelial growth factor (VEGF) is a critical angiogenesis biomarker associated with various pathological conditions, including cancer. This study leverages pre-biotinylated FcγRI interactions with IgG1-type monoclonal antibodies to develop a sensitive VEGF detection method. Utilizing surface plasmon resonance (SPR) technology, we characterized the binding dynamics of immobilized biotinylated FcγRI to an IgG1-type antibody, Bevacizumab (AVT), through kinetic studies and investigated suitable conditions for sensor surface regeneration. Subsequently, we characterized the binding of FcγRI-captured AVT to VEGF, calculating kinetic constants and binding affinity. A calibration curve was established to analyze the VEGF quantification capacity and accuracy of the biosensor, computing the limits of blank, detection, and quantification at a 95% confidence interval. Additionally, the specificity of the biosensor for VEGF over other protein analytes was assessed. This innovative biomimetic approach enabled FcγRI-mediated site-specific AVT capture, establishing a stable and reusable platform for detecting and accurately quantifying VEGF. The results indicate the effectiveness of the plasmonic sensor platform for VEGF detection, making it suitable for research applications and, potentially, clinical diagnostics. Utilizing FcγRI-IgG1 antibody binding, this study highlights the industrial and clinical value of advanced biosensing technologies, offering insights to enhance therapeutic monitoring and improve outcomes in anti-VEGF therapies. Full article

(This article belongs to the Special Issue Advances in Plasmonic Biosensing Technology)

22 pages, 3998 KiB

Open AccessReview

Mitigating Antibiotic Resistance: The Utilization of CRISPR Technology in Detection

by Xuejiao Zhang, Zhaojie Huang, Yanxia Zhang, Wen Wang, Zihong Ye, Pei Liang, Kai Sun, Wencheng Kang, Qiao Tang and Xiaoping Yu

Biosensors 2024, 14(12), 633; https://doi.org/10.3390/bios14120633 - 20 Dec 2024

Abstract

Antibiotics, celebrated as some of the most significant pharmaceutical breakthroughs in medical history, are capable of eliminating or inhibiting bacterial growth, offering a primary defense against a wide array of bacterial infections. However, the rise in antimicrobial resistance (AMR), driven by the widespread [...] Read more.

Antibiotics, celebrated as some of the most significant pharmaceutical breakthroughs in medical history, are capable of eliminating or inhibiting bacterial growth, offering a primary defense against a wide array of bacterial infections. However, the rise in antimicrobial resistance (AMR), driven by the widespread use of antibiotics, has evolved into a widespread and ominous threat to global public health. Thus, the creation of efficient methods for detecting resistance genes and antibiotics is imperative for ensuring food safety and safeguarding human health. The clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (Cas) systems, initially recognized as an adaptive immune defense mechanism in bacteria and archaea, have unveiled their profound potential in sensor detection, transcending their notable gene-editing applications. CRISPR/Cas technology employs Cas enzymes and guides RNA to selectively target and cleave specific DNA or RNA sequences. This review offers an extensive examination of CRISPR/Cas systems, highlighting their unique attributes and applications in antibiotic detection. It outlines the current utilization and progress of the CRISPR/Cas toolkit for identifying both nucleic acid (resistance genes) and non-nucleic acid (antibiotic micromolecules) targets within the field of antibiotic detection. In addition, it examines the current challenges, such as sensitivity and specificity, and future opportunities, including the development of point-of-care diagnostics, providing strategic insights to facilitate the curbing and oversight of antibiotic-resistance proliferation. Full article

(This article belongs to the Special Issue Advanced Nanozyme for Biosensors)

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17 pages, 1548 KiB

Open AccessArticle

Development of RT h-CLAT, a Rapid Assessment Method for Skin Sensitizers Using THP-1 Cells as a Biosensor

by Hiroki Koyama, Ayami Maeda, Peiqi Zhai, Keiichiro Koiwai and Kouichi Kurose

Biosensors 2024, 14(12), 632; https://doi.org/10.3390/bios14120632 - 20 Dec 2024

Abstract

In recent years, in vitro skin sensitization assays have been recommended as animal-free alternatives for the safety assessment of cosmetics and topical drugs, and these methods have been adopted in OECD test guidelines. However, existing assays remain complex and costly. To address this, [...] Read more.

In recent years, in vitro skin sensitization assays have been recommended as animal-free alternatives for the safety assessment of cosmetics and topical drugs, and these methods have been adopted in OECD test guidelines. However, existing assays remain complex and costly. To address this, we recently developed a more efficient, cost-effective, and accurate method for evaluating skin sensitizers by using immune cell-derived THP-1 cells as a biosensor, coupled with an RT-PCR-based assay. In this study, we further refined this method to enable even faster assessment of skin sensitization. By performing comprehensive RNA sequencing (RNA-Seq) analysis, we examined gene expression profiles induced by sensitizers in THP-1 cells to identify potential sensitization markers, ultimately selecting the optimal markers and conditions for evaluation. Our findings indicate that after exposing a test chemical to THP-1 cells for 5 h, measuring the expression levels of the JUN and HMOX1 genes via real-time PCR allows for a reliable assessment of sensitization. A test compound is defined as a sensitizer if either gene shows a more than two-fold increase in its expression compared to the control. Applying this improved method, designated as RT h-CLAT, we evaluated the sensitization potential of 43 chemicals. The results demonstrated higher accuracy compared to the human cell line activation test (h-CLAT) listed in the OECD guidelines, while also reducing the required assessment time from two days to one. Full article

(This article belongs to the Special Issue Advances in Immunoassay Biosensing Platform for Point-of-Care Diagnostics)

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11 pages, 908 KiB

Open AccessArticle

Evaluation of Photoplethysmography-Based Monitoring of Respiration Rate During High-Intensity Interval Training: Implications for Healthcare Monitoring

by Marjolein Muller, Kambiz Ebrahimkheil, Tara Vijgeboom, Casper van Eijck and Eelko Ronner

Biosensors 2024, 14(12), 631; https://doi.org/10.3390/bios14120631 - 20 Dec 2024

Abstract

Monitoring respiration rate (RR) is crucial in various healthcare settings, particularly during demanding (physical) activities where respiratory dynamics are critical indicators of health status. This study aimed to evaluate the accuracy of photoplethysmography (PPG)-based monitoring of RR during high-intensity interval training (HIIT) and [...] Read more.

Monitoring respiration rate (RR) is crucial in various healthcare settings, particularly during demanding (physical) activities where respiratory dynamics are critical indicators of health status. This study aimed to evaluate the accuracy of photoplethysmography (PPG)-based monitoring of RR during high-intensity interval training (HIIT) and its potential applications in healthcare. Between January and March 2024, healthy volunteers participated in a cycling HIIT session with increasing resistance levels. The RR measurements obtained using the PPG-based CardioWatch 287-2 (Corsano Health) were compared with an ECG patch-derived (Vivalink) reference. Subgroup analyses were conducted based on skin type and sex. A total of 35 participants contributed 1794 paired RR measurements. The PPG algorithm for RR monitoring showed an average root mean square (Arms) error of 2.13 breaths per minute (brpm), a bias of −0.09 brpm, and limits of agreement (LoA) from −4.28 to 4.09 brpm. Results were consistent across the different demographic subgroups. The CardioWatch 287-2 therefore demonstrated reliable RR monitoring during HIIT, supporting its potential use in healthcare settings for continuous, non-invasive respiratory monitoring, particularly in physical rehabilitation and chronic respiratory condition management. Full article

(This article belongs to the Section Biosensors and Healthcare)

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16 pages, 2846 KiB

Open AccessArticle

Development of Single-Walled Carbon Nanotube-Based Electrodes with Enhanced Dispersion and Electrochemical Properties for Blood Glucose Monitoring

by Dong-Sup Kim, Abdus Sobhan, Jun-Hyun Oh, Jahyun Lee, Chulhwan Park and Jinyoung Lee

Biosensors 2024, 14(12), 630; https://doi.org/10.3390/bios14120630 - 19 Dec 2024

Abstract

The evolution of high-performance electrode materials has significantly impacted the development of real-time monitoring biosensors, emphasizing the need for compatibility with biomaterials and robust electrochemical properties. This work focuses on creating electrode materials utilizing single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), [...] Read more.

The evolution of high-performance electrode materials has significantly impacted the development of real-time monitoring biosensors, emphasizing the need for compatibility with biomaterials and robust electrochemical properties. This work focuses on creating electrode materials utilizing single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), specifically examining their dispersion behavior and electrochemical characteristics. By using ultrasonic waves, we analyzed the dispersion of CNTs in various solvents, including N, N-dimethylformamide (DMF), deionized water (DW), ethanol, and acetone. The findings revealed that SWCNTs achieved optimal dispersion without precipitation in DMF. Additionally, we observed that the electrical resistance decreased as the concentration of SWCNTs increased from 0.025 to 0.4 g/L, with significant conductivity enhancements noted between 0.2 g/L and 0.4 g/L in DMF. In constructing the biosensor platform, we employed 1-pyrenebutanoic acid succinimidyl ester (PBSE) as a linker molecule, while glucose oxidase (Gox) served as the binding substrate. The interaction between Gox and glucose led to a notable decrease in the biosensor’s resistance values as glucose concentrations ranged from 0.001 to 0.1 M. These results provide foundational insights into the development of SWCNT-based electrode materials and suggest a promising pathway toward the next generation of efficient and reliable biosensors. Full article

(This article belongs to the Special Issue Novel Nanomaterials and Nanotechnology: From Fabrication Methods and Improvement Strategies to Applications in Biosensing and Biomedicine (2nd Edition))

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36 pages, 12089 KiB

Open AccessReview

Sensing Technologies for Outdoor/Indoor Farming

by Luwei Wang, Mengyao Xiao, Xinge Guo, Yanqin Yang, Zixuan Zhang and Chengkuo Lee

Biosensors 2024, 14(12), 629; https://doi.org/10.3390/bios14120629 - 19 Dec 2024

Abstract

To face the increasing requirement for grains as the global population continues to grow, improving both crop yield and quality has become essential. Plant health directly impacts crop quality and yield, making the development of plant health-monitoring technologies essential. Variable sensing technologies for [...] Read more.

To face the increasing requirement for grains as the global population continues to grow, improving both crop yield and quality has become essential. Plant health directly impacts crop quality and yield, making the development of plant health-monitoring technologies essential. Variable sensing technologies for outdoor/indoor farming based on different working principles have emerged as important tools for monitoring plants and their microclimates. These technologies can detect factors such as plant water content, volatile organic compounds (VOCs), and hormones released by plants, as well as environmental conditions like humidity, temperature, wind speed, and light intensity. To achieve comprehensive plant health monitoring for multidimensional assessment, multimodal sensors have been developed. Non-invasive monitoring approaches are also gaining attention, leveraging biocompatible and flexible sensors for plant monitoring without interference with its natural growth. Furthermore, wireless data transmission is crucial for real-time monitoring and efficient farm management. Reliable power supplies for these systems are vital to ensure continuous operation. By combining wearable sensors with intelligent data analysis and remote monitoring, modern agriculture can achieve refined management, resource optimization, and sustainable production, offering innovative solutions to global food security and environmental challenges. Full article

(This article belongs to the Special Issue Wearable Sensors for Plant Health Monitoring)

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13 pages, 975 KiB

Open AccessPerspective

Wearable Sensors and Motion Analysis for Neurological Patient Support

by Peter Dabnichki and Toh Yen Pang

Biosensors 2024, 14(12), 628; https://doi.org/10.3390/bios14120628 - 19 Dec 2024

Abstract

This work discusses the state of the art and challenges in using wearable sensors for the monitoring of neurological patients. The authors share their experience from their participation in numerous projects, ranging from drug trials to rehabilitation intervention assessment, and identify the obstacles [...] Read more.

This work discusses the state of the art and challenges in using wearable sensors for the monitoring of neurological patients. The authors share their experience from their participation in numerous projects, ranging from drug trials to rehabilitation intervention assessment, and identify the obstacles in the way of the integrated adoption of wearable sensors in clinical and rehabilitation practices for neurological patients. Several highly promising developments are outlined and analyzed. It is considered that intelligent textiles are an attractive option, as they offer an esthetic outlook to and positive interaction with their users. Full article

(This article belongs to the Special Issue Advances in Flexible Bioelectronics and Intelligent Biosensing Systems)

32 pages, 8535 KiB

Open AccessReview

Nanopipettes as a Potential Diagnostic Tool for Selective Nanopore Detection of Biomolecules

by Regina M. Kuanaeva, Alexander N. Vaneev, Petr V. Gorelkin and Alexander S. Erofeev

Biosensors 2024, 14(12), 627; https://doi.org/10.3390/bios14120627 - 19 Dec 2024

Abstract

Nanopipettes, as a class of solid-state nanopores, have evolved into universal tools in biomedicine for the detection of biomarkers and different biological analytes. Nanopipette-based methods combine high sensitivity, selectivity, single-molecule resolution, and multifunctionality. The features have significantly expanded interest in their applications for [...] Read more.

Nanopipettes, as a class of solid-state nanopores, have evolved into universal tools in biomedicine for the detection of biomarkers and different biological analytes. Nanopipette-based methods combine high sensitivity, selectivity, single-molecule resolution, and multifunctionality. The features have significantly expanded interest in their applications for the biomolecular detection, imaging, and molecular diagnostics of real samples. Moreover, the ease of manufacturing nanopipettes, coupled with their compatibility with fluorescence and electrochemical methods, makes them ideal for portable point-of-care diagnostic devices. This review summarized the latest progress in nanopipette-based nanopore technology for the detection of biomarkers, DNA, RNA, proteins, and peptides, in particular β-amyloid or α-synuclein, emphasizing the impact of technology on molecular diagnostics. By addressing key challenges in single-molecule detection and expanding applications in diverse biological areas, nanopipettes are poised to play a transformative role in the future of personalized medicine. Full article

(This article belongs to the Section Biosensors and Healthcare)

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19 pages, 7793 KiB

Open AccessArticle

A Ratiometric Fluorescence Method Based on PCN-224-DABA for the Detection of Se(IV) and Fe(III)

by Mao-Ling Luo, Guo-Ying Chen, Wen-Jia Li, Jia-Xin Li, Tong-Qing Chai, Zheng-Ming Qian and Feng-Qing Yang

Biosensors 2024, 14(12), 626; https://doi.org/10.3390/bios14120626 - 19 Dec 2024

Abstract

In this study, 3,4-diaminobenzoic acid (DABA) was introduced into the porphyrin metal–organic framework (PCN-224) for the first time to prepare a ratiometric fluorescent probe (PCN-224-DABA) to quantitatively detect ferric iron (Fe(III)) and selenium (IV) (Se(IV)). The fluorescence attributed to the DABA of PCN-224-DABA [...] Read more.

In this study, 3,4-diaminobenzoic acid (DABA) was introduced into the porphyrin metal–organic framework (PCN-224) for the first time to prepare a ratiometric fluorescent probe (PCN-224-DABA) to quantitatively detect ferric iron (Fe(III)) and selenium (IV) (Se(IV)). The fluorescence attributed to the DABA of PCN-224-DABA at 345 nm can be selectively quenched by Fe(III) and Se(IV), but the fluorescence emission peak attributed to tetrakis (4-carboxyphenyl) porphyrin (TCPP) at 475 nm will not be disturbed. Therefore, the ratio of I_345nm/I_475nm with an excitation wavelength of 270 nm can be designed to determine Fe(III) and Se(IV). After the experimental parameters were systematically optimized, the developed method shows good selectivity and interference resistance for Fe(III) and Se(IV) detection, and has good linearity in the ranges of 0.01–4 μM and 0.01–15 μM for Fe(III) and Se(IV) with a limit of detection of 0.045 μM and 0.804 μM, respectively. Furthermore, the quenching pattern was investigated through the Stern–Volmer equation, and the results suggest that both Se(IV) and Fe(III) quenched on PCN-224-DABA can be attributed to the dynamic quenching. Finally, the constructed ratiometric fluorescent probe was applied in the spiked detection of lake water samples, which shows good applicability in real sample analysis. Moreover, the Fe(III) and Se(IV) contents in spinach and selenium-enriched rice were determined, respectively. Full article

(This article belongs to the Special Issue Advances in Nanozyme-Based Biosensors for Colorimetric and Fluorescence Analyses)

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26 pages, 2814 KiB

Open AccessReview

Recent Advances of Strategies and Applications in Aptamer-Combined Metal Nanocluster Biosensing Systems

by Ki-Beom Kim, Sang-Ho Kim and Seung-Min Yoo

Biosensors 2024, 14(12), 625; https://doi.org/10.3390/bios14120625 - 18 Dec 2024

Abstract

Metal nanoclusters (NCs) are promising alternatives to organic dyes and quantum dots. These NCs exhibit unique physical and chemical properties, such as fluorescence, chirality, magnetism and catalysis, which contribute to significant advancements in biosensing, biomedical diagnostics and therapy. Through adjustments in composition, size, [...] Read more.

Metal nanoclusters (NCs) are promising alternatives to organic dyes and quantum dots. These NCs exhibit unique physical and chemical properties, such as fluorescence, chirality, magnetism and catalysis, which contribute to significant advancements in biosensing, biomedical diagnostics and therapy. Through adjustments in composition, size, chemical environments and surface ligands, it is possible to create NCs with tunable optoelectronic and catalytic activity. This review focuses on the integration of aptamers with metal NCs, detailing molecular detection strategies that utilise the effect of aptamers on optical signal emission of metal NC-based biosensing systems. This review also highlights recent advancements in biosensing and biomedical applications, as well as illustrative case studies. To conclude, the strengths, limitations, current challenges and prospects for metal NC-based systems were examined. Full article

(This article belongs to the Special Issue Biomaterials for Biosensing Applications)

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19 pages, 1516 KiB

Open AccessArticle

Impedimetric Biosensors for the Quantification of Serum Biomarkers for Early Detection of Lung Cancer

by Mahdi Arabnejad, Ibtisam E. Tothill and Iva Chianella

Biosensors 2024, 14(12), 624; https://doi.org/10.3390/bios14120624 - 18 Dec 2024

Abstract

Lung cancer is the most common type of cancer diagnosed worldwide and is also among the most fatal. Early detection, before symptoms become evident, is fundamental for patients’ survival. Therefore, several lung cancer biomarkers have been proposed to enable a prompt diagnosis, including [...] Read more.

Lung cancer is the most common type of cancer diagnosed worldwide and is also among the most fatal. Early detection, before symptoms become evident, is fundamental for patients’ survival. Therefore, several lung cancer biomarkers have been proposed to enable a prompt diagnosis, including neuron-specific enolase (NSE) and carcinoembryonic antigen (CEA). NSE and CEA are two serum proteins whose elevated levels have been associated with lung cancer. Hence, in this study, impedimetric biosensors (immunosensors) able to quantify NSE and CEA were developed as proof-of-concept devices for lung cancer diagnosis. The sensing platform exploited for the immunosensors comprises a novel combination of a magnetic platform, screen-printed gold electrode (SPGE), and magnetic nanobeads (MB). The MB were functionalized with antibodies to capture the analyte from the sample and to move it over the sensing area. The immunosensors were then developed by immobilizing another set of antibodies for either CEA or NSE on the SPGE through formation of self-assembled monolayer (SAM). The second set of antibodies enabled a sandwich assay to be formed on the surface of the sensor, while MB manipulation was applied during the sensor performance to depict a microfluidic system and increase antigen–antibody complex formation prior to CEA or NSE detection and quantification. The optimized immunosensors were successfully tested to measure various concentrations of CEA and NSE (0–100 ng/mL) in both phosphate buffer and 100% human serum samples. Clinically relevant detection limits of 0.26 ng/mL and 0.18 ng/mL in buffer and 0.76 ng/mL and 0.52 ng/mL in 100% serum for CEA and NSE, respectively, were achieved via electrochemical impedance spectroscopy with the use of potassium ferri/ferrocyanide as a redox probe. Hence, the two immunosensors demonstrated great potential as tools to be implemented for the early detection of lung cancer. Full article

(This article belongs to the Special Issue Immunosensors: Design and Applications)

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17 pages, 9476 KiB

Open AccessArticle

Portable Amperometric Biosensor Enhanced with Enzyme-Ternary Nanocomposites for Prostate Cancer Biomarker Detection

by Thenmozhi Rajarathinam, Sivaguru Jayaraman, Chang-Seok Kim, Jaewon Lee and Seung-Cheol Chang

Biosensors 2024, 14(12), 623; https://doi.org/10.3390/bios14120623 - 18 Dec 2024

Abstract

Enzyme-based portable amperometric biosensors are precise and low-cost medical devices used for rapid cancer biomarker screening. Sarcosine (Sar) is an ideal biomarker for prostate cancer (PCa). Because human serum and urine contain complex interfering substances that can directly oxidize at the electrode surface, [...] Read more.

Enzyme-based portable amperometric biosensors are precise and low-cost medical devices used for rapid cancer biomarker screening. Sarcosine (Sar) is an ideal biomarker for prostate cancer (PCa). Because human serum and urine contain complex interfering substances that can directly oxidize at the electrode surface, rapid Sar screening biosensors are relatively challenging and have rarely been reported. Therefore, highly sensitive and selective amperometric biosensors that enable real-time measurements within <1.0 min are needed. To achieve this, a chitosan–polyaniline polymer nanocomposite (CS–PANI NC), a carrier for dispersing mesoporous carbon (MC), was synthesized and modified on a screen-printed carbon electrode (SPCE) to detect hydrogen peroxide (H₂O₂). The sarcosine oxidase (SOx) enzyme-immobilized CS–PANI–MC-2 ternary NCs were referred to as supramolecular architectures (SMAs). The excellent electron transfer ability of the SMA-modified SPCE (SMA/SPCE) sensor enabled highly sensitive H₂O₂ detection for immediate trace Sar biomarker detection. Therefore, the system included an SMA/SPCE coupled to a portable potentiostat linked to a smartphone for data acquisition. The high catalytic activity, porous architecture, and sufficient biocompatibility of CS–PANI–MC ternary NCs enabled bioactivity retention and immobilized SOx stability. The fabricated biosensor exhibited a detection limit of 0.077 μM and sensitivity of 8.09 μA mM⁻¹ cm⁻² toward Sar, demonstrating great potential for use in rapid PCa screening. Full article

(This article belongs to the Special Issue Integrated Biosensing for Point-of-Care Detection)

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11 pages, 2157 KiB

Open AccessArticle

Wearable Fabric System for Sarcopenia Detection

by Zhenhe Huang, Qiuqian Ou, Dan Li, Yuanyi Feng, Liangling Cai, Yue Hu and Hongwei Chu

Biosensors 2024, 14(12), 622; https://doi.org/10.3390/bios14120622 - 18 Dec 2024

Abstract

Sarcopenia has been a serious concern in the context of an increasingly aging global population. Existing detection methods for sarcopenia are severely constrained by cumbersome devices, the necessity for specialized personnel, and controlled experimental environments. In this study, we developed an innovative wearable [...] Read more.

Sarcopenia has been a serious concern in the context of an increasingly aging global population. Existing detection methods for sarcopenia are severely constrained by cumbersome devices, the necessity for specialized personnel, and controlled experimental environments. In this study, we developed an innovative wearable fabric system based on conductive fabric and flexible sensor array. This fabric system demonstrates remarkable pressure-sensing capabilities, with a high sensitivity of 18.8 kPa⁻¹ and extraordinary stability. It also exhibits excellent flexibility for wearable applications. By interacting with different parts of the human body, it facilitates the monitoring of various physiological activities, such as pulse dynamics, finger movements, speaking, and ambulation. Moreover, this fabric system can be seamlessly integrated into sole to track critical indicators of sarcopenia patients, such as walking speed and gait. Clinical evaluations have shown that this fabric system can effectively detect variations in indicators relevant to sarcopenia patients, proving that it offers a straightforward and promising approach for the diagnosis and assessment of sarcopenia. Full article

(This article belongs to the Special Issue Advanced Bioelectronics for Healthcare Monitoring and Disease Diagnosis)

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14 pages, 1387 KiB

Open AccessArticle

Continuous Estimation of Blood Pressure by Utilizing Seismocardiogram Signal Features in Relation to Electrocardiogram

by Aleksandra Zienkiewicz, Vesa Korhonen, Vesa Kiviniemi and Teemu Myllylä

Biosensors 2024, 14(12), 621; https://doi.org/10.3390/bios14120621 - 17 Dec 2024

Abstract

There is an ongoing search for a reliable and continuous method of noninvasive blood pressure (BP) tracking. In this study, we investigate the feasibility of utilizing seismocardiogram (SCG) signals, i.e., chest motion caused by cardiac activity, for this purpose. This research is novel [...] Read more.

There is an ongoing search for a reliable and continuous method of noninvasive blood pressure (BP) tracking. In this study, we investigate the feasibility of utilizing seismocardiogram (SCG) signals, i.e., chest motion caused by cardiac activity, for this purpose. This research is novel in examining the temporal relationship between the SCG-measured isovolumic moment and the electrocardiogram (PEP_IM). Additionally, we compare these results with the traditionally measured pre-ejection period with the aortic opening marked as an endpoint (PEP_AO). The accuracy of the BP estimation was evaluated beat to beat against invasively measured arterial BP. Data were collected on separate days as eighteen sets from nine subjects undergoing a medical procedure with anesthesia. Results for PEP_IM showed a correlation of 0.67 ± 0.18 (p < 0.001), 0.66 ± 0.17 (p < 0.001), and 0.67 ± 0.17 (p < 0.001) when compared to systolic BP, diastolic BP, and mean arterial pressure (MAP), respectively. Corresponding results for PEP_AO were equal to 0.61 ± 0.22 (p < 0.001), 0.61 ± 0.21 (p < 0.001), and 0.62 ± 0.22 (p < 0.001). Values of PEP_IM were used to estimate MAP using two first-degree models, the linear regression model (achieved RMSE of 11.7 ± 4.0 mmHg) and extended model with HR (RMSE of 10.8 ± 4.2 mmHg), and two corresponding second-degree models (RMSE of 10.8 ± 3.7 mmHg and RMSE of 8.5 ± 3.4 mmHg for second-degree polynomial and second-degree extended, respectively). In the intrasubject testing of the second-degree model extended with HR based on PEP_IM values, the mean error of MAP estimation in three follow-up measurements was in the range of 7.5 to 10.5 mmHg, without recalibration. This study demonstrates the method’s potential for further research, particularly given that both proximal and distal pulses are measured in close proximity to the heart and cardiac output. This positioning may enhance the method’s capacity to more accurately reflect central blood pressure compared to peripheral measurements. Full article

(This article belongs to the Special Issue Advanced Bioelectronics for Healthcare Monitoring and Disease Diagnosis)

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11 pages, 1803 KiB

Open AccessArticle

Paper-Based Aptasensor Assay for Detection of Food Adulterant Sildenafil

by Murat Kavruk and Veli Cengiz Ozalp

Biosensors 2024, 14(12), 620; https://doi.org/10.3390/bios14120620 - 17 Dec 2024

Abstract

Sildenafil is used to treat erectile dysfunction and pulmonary arterial hypertension but is often illicitly added to energy drinks and chocolates. This study introduces a lateral flow strip test using aptamers specific to sildenafil for detecting its illegal presence in food. The process [...] Read more.

Sildenafil is used to treat erectile dysfunction and pulmonary arterial hypertension but is often illicitly added to energy drinks and chocolates. This study introduces a lateral flow strip test using aptamers specific to sildenafil for detecting its illegal presence in food. The process involved using graphene oxide SELEX to identify high-affinity aptamers, which were then converted into molecular gate structures on mesoporous silica nanoparticles, creating a unique signaling system. This system was integrated into lateral flow chromatography strips and tested on buffers and chocolate samples containing sildenafil. The method simplifies the lateral flow assay (LFA) for small molecules and provides a tool for signal amplification. The detection limit for these strips was found to be 68.2 nM (31.8 µg/kg) in spiked food samples. Full article

(This article belongs to the Special Issue Integrated Biosensing for Point-of-Care Detection)

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11 pages, 3147 KiB

Open AccessCommunication

Active Surface-Enhanced Raman Scattering Platform Based on a 2D Material–Flexible Nanotip Array

by Yong Bin Kim, Satyabrat Behera, Dukhyung Lee, Seon Namgung, Kyoung-Duck Park, Dai-Sik Kim and Bamadev Das

Biosensors 2024, 14(12), 619; https://doi.org/10.3390/bios14120619 - 15 Dec 2024

Abstract

Two-dimensional materials with a nanostructure have been introduced as promising candidates for SERS platforms for sensing application. However, the dynamic control and tuning of SERS remains a long-standing problem. Here, we demonstrated active tuning of the enhancement factor of the first- and second-order [...] Read more.

Two-dimensional materials with a nanostructure have been introduced as promising candidates for SERS platforms for sensing application. However, the dynamic control and tuning of SERS remains a long-standing problem. Here, we demonstrated active tuning of the enhancement factor of the first- and second-order Raman mode of monolayer (1L) MoS₂ transferred onto a flexible metallic nanotip array. Using mechanical strain, the enhancement factor of 1L MoS₂/nanotip is modulated from 1.23 to 8.72 for 2LA mode. For the same mode, the SERS intensity is enhanced by ~31 times when silver nanoparticles of ~13 nm diameter are deposited on 1L MoS₂/nanotip, which is tuned up to ~34 times by compressive strain. The change in SERS enhancement factor is due to the decrease (increase) in gap width as the sample is bent inwardly (outwardly). This is corroborated by FEM structural and electromagnetic simulation. We also observed significant control over mode peak and linewidth, which may have applications in biosensing, chemical detection, and optoelectronics. Full article

(This article belongs to the Special Issue Micro-nano Optic-Based Biosensing Technology and Strategy)

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11 pages, 2016 KiB

Open AccessArticle

Entropy-Driven Molecular Beacon Assisted Special RCA Assay with Enhanced Sensitivity for Room Temperature DNA Biosensing

by Shurui Tao, Yi Long and Guozhen Liu

Biosensors 2024, 14(12), 618; https://doi.org/10.3390/bios14120618 - 15 Dec 2024

Abstract

The Phi29 DNA polymerase is renowned for its processivity in synthesizing single-stranded DNA amplicons by rolling around a circularized DNA template. However, DNA synthesis rolling circle amplification (RCA) is significantly hindered by the secondary structure in the circular template. To overcome this limitation, [...] Read more.

The Phi29 DNA polymerase is renowned for its processivity in synthesizing single-stranded DNA amplicons by rolling around a circularized DNA template. However, DNA synthesis rolling circle amplification (RCA) is significantly hindered by the secondary structure in the circular template. To overcome this limitation, an engineered circular template without secondary structure could be utilized to improve the sensitivity of RCA-based assays without increasing its complexity. We herein proposed an entropy-driven special RCA technology for the detection of HPV16 E7 gene at room temperature. The strategy is composed of a molecular beacon containing a loop region for nucleic acid target recognition and a stem region to initiate RCA. With the target analyte, the stem region of the molecular beacon will be exposed and then hybridized with a special circular template to initiate the DNA amplification. We tested different designs of the molecular beacon sequence and optimized the assay’s working conditions. The assay achieved a sensitivity of 1 pM in 40 min at room temperature. The sensitivity of this assay, at 1 pm, is about a hundred-fold greater than that of conventional linear RCA performed in solution. Our proposed sensor can be easily reprogrammed for detecting various nucleic acid markers by altering the molecular beacon’s loop. Its simplicity, rapid assay time, and low cost make it superior to RCA sensors that utilize similar strategies. Full article

(This article belongs to the Special Issue Programmable Nuclease-Based Biosensors for Medical Diagnostics, Food Safety and beyond Applications)

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