Chemosensors

2023

Jump to: 2022

14 pages, 5509 KiB

Open AccessArticle

Illuminating Histidine-Deficient Intracellular Environments: A Novel Whole-Cell Microbial Fluorescence Sensor

by Xinyi Li, Zezhou Li and Meiping Zhao

Chemosensors 2023, 11(10), 515; https://doi.org/10.3390/chemosensors11100515 - 30 Sep 2023

Viewed by 1450

Abstract

Histidine is an essential amino acid with significant implications for human growth and neuromodulation. Its intracellular concentration, whether increased or decreased, can indicate different diseases. While various methods exist for measuring elevated histidine levels, there remains a significant lack of sensors capable of [...] Read more.

Histidine is an essential amino acid with significant implications for human growth and neuromodulation. Its intracellular concentration, whether increased or decreased, can indicate different diseases. While various methods exist for measuring elevated histidine levels, there remains a significant lack of sensors capable of actively responding to histidine deficiency within cells and releasing strong signals. In this study, we exploited the high induction levels of the his operon in S. Typhimurium SL1344, a histidine auxotroph, within a histidine-deficient environment, to develop a specific bacterial sensor with sensitivity towards low histidine concentrations. By employing plasmid vectors with differing copy numbers, we developed two distinct bacterial fluorescence sensors, both capable of actively responding to histidine deficiency and emitting detectable fluorescence signals within either culture mediums or live cells. The SL1344-pGEX sensor, with a high copy number, exhibited remarkable sensitivity and selectivity to histidine in the range of 0 to 50 μM. Notably, even a minimal addition of histidine (approximately 2.5 μM) to the M9 medium led to observable fluorescence reduction, rendering it highly suitable for monitoring histidine-deficient cellular environments. In contrast, the low-copy-number SL1344-pSB3313 sensor exhibits a broader response range, capable of tracking more extensive shifts in histidine concentrations. These sensors allow for sensitive in situ detection of intracellular histidine concentrations in various live cells, particularly responding to real-time changes in cellular histidine levels. This provides a powerful tool for investigating histidine deficiency-related biological processes, the mechanisms of associated diseases, and the assessment and optimization of therapeutic strategies. Full article

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13 pages, 4189 KiB

Open AccessArticle

Sensitive Evanescence-Field Waveguide Interferometer for Aqueous Nitro-Explosive Sensing

by Wen Wang, Guowei Deng, Zhanwei Hu, Kaixin Chen and Jieyun Wu

Chemosensors 2023, 11(4), 246; https://doi.org/10.3390/chemosensors11040246 - 15 Apr 2023

Cited by 3 | Viewed by 1793

Abstract

The development of novel chemical nitro-explosive sensors with high sensitivity, low cost and a compact size is essential for homeland security, environmental protection and addressing military challenges. Polymeric optical waveguides based on refractive index sensing are widely used in biochemical detection due to [...] Read more.

The development of novel chemical nitro-explosive sensors with high sensitivity, low cost and a compact size is essential for homeland security, environmental protection and addressing military challenges. Polymeric optical waveguides based on refractive index sensing are widely used in biochemical detection due to their advantages of large-scale integration, low cost, high sensitivity and anti-electromagnetic interference. In this study, we designed and fabricated a polymer waveguide Mach–Zehnder interferometer (MZI) sensor to detect 2,4-dinitrotoluene (DNT) in water. One phase shifter of the MZI waveguide was functionalized by coating a thin cladding layer of polycarbonate with dipolar chromophores and used as the sensing arm; the other arm was coated with passive epoxy resin cladding and used as the reference arm. The phase difference between the two arms of the MZI was modulated using the refractive index (RI) change in the polycarbonate cladding when dipolar chromophores interacted with electro-deficient DNT. The theoretical sensitivity of the designed MZI can reach up to 24,696 nm/RIU. When used for explosive detection, our fabricated sensor had a maximum wavelength shift of 4.465 nm and good linear relation, with an R² of 0.96 between the wavelength shift and a concentration ranging from 3.5 × 10⁻⁵ to 6.3 × 10⁻⁴ mol/L. The sensitivity of our device was 6821.6 nm/(mol/L). The design of an unbalanced MZI sensor, together with the sensing material, provides a new approach to using low-cost, compact and highly sensitive devices for in-field explosive detection. Full article

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23 pages, 7223 KiB

Open AccessReview

Trimethyl Lock Quinone-Based Organic Molecular Probes for NQO1 Sensing and Imaging

by Kun Chen, Shuai Xu, Zhiling Song and Ke Li

Chemosensors 2023, 11(4), 221; https://doi.org/10.3390/chemosensors11040221 - 4 Apr 2023

Cited by 4 | Viewed by 2398

Abstract

NAD(P)H: quinone oxidoreductase isozyme 1 (NQO1) is a flavoenzyme and involved in protection against oxidative stress and the regulation of metabolic functions, which is strongly implicated in neurodegenerative diseases and carcinogenic processes. Furthermore, NQO1 is also involved in the modes of action of [...] Read more.

NAD(P)H: quinone oxidoreductase isozyme 1 (NQO1) is a flavoenzyme and involved in protection against oxidative stress and the regulation of metabolic functions, which is strongly implicated in neurodegenerative diseases and carcinogenic processes. Furthermore, NQO1 is also involved in the modes of action of redox-active drugs (e.g., antimalarials). Determining the activity and localization of NQO1 in living organisms is of great importance for early disease diagnosis and therapy. As a promising and convenient biosensing technique, trimethyl lock quinone-based organic molecular probes have been well established for the specific detection and imaging of NQO1 in living cells and in vivo. In this review, the recent progress of NQO1 probes based on organic small molecules is summarized from the perspectives of molecular design strategies, sensing mechanisms and bioimaging applications. We also elucidate the potential limitations and prospects of current NQO1 probes to further promote the development of versatile imaging tools for NQO1-related biomedical investigation. Full article

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15 pages, 6151 KiB

Open AccessArticle

Highly Selective and Sensitive Sensor Based IL and CMC-MWCNTs Nanocomposite for Rutin Determination

by Xin Meng, Bao-Lin Xiao, Xin-Yan Song, Xin-Xin Ma, Yang-Yang Li, Lin-Lin Ma, Yu-Jie Chen, Yu-Ying Li, Ke-Xin Xu, Jian-She Wei, Tao Hong, Ali Akbar Moosavi-Movahedi and Jun Hong

Chemosensors 2023, 11(3), 171; https://doi.org/10.3390/chemosensors11030171 - 2 Mar 2023

Cited by 2 | Viewed by 1976

Abstract

Rutin is a natural antioxidant flavonoid compound with anti-inflammatory, antioxidant, and antiviral effects that is used to prepare drugs with wide application in clinical treatment. Therefore, the quantitative detection of rutin has important practical significance. In this work, a novel electrochemical sensor based [...] Read more.

Rutin is a natural antioxidant flavonoid compound with anti-inflammatory, antioxidant, and antiviral effects that is used to prepare drugs with wide application in clinical treatment. Therefore, the quantitative detection of rutin has important practical significance. In this work, a novel electrochemical sensor based on glassy carbon electrodes (GCEs) modified with sodium carboxymethylcellulose (CMC), multi-walled carbon nanotubes (MWCNTs), and 1-butyl-3-methylimid (ionic liquid, IL) was developed for the super-sensitive detection of the flavonoid rutin. The properties of these modified materials were analyzed by transmission electron microscope (TEM), cyclic voltammograms (CVs), and electrochemical-impedance spectroscopy (EIS). CMC was used to disperse MWCNTs to further enhance their hydrophilicity and biocompatibility. The modified MWCNTs improved the sensitivity of rutin detection. The square-wave voltammetry (SWV) technique showed that the linear range of rutin concentration determination was 0.01 μM to 1 µM and 1 µM to 10 µM. The minimum concentration detection of rutin was 0.83 nM and 6.6 nM, respectively. The proposed sensor presented good selectivity for rutin and successfully analyzed rutin content in the pharmaceutical rutin tablets. These results are consistent with those measured by ultra-high-performance liquid chromatography (UHPLC). Therefore, this sensor has latent application value in the analysis of rutin in food and drug tablets and nutraceutical samples. Full article

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12 pages, 2202 KiB

Open AccessArticle

Discovering a Dihydrofluorescein Analogue as a Promising Fluorescence Substrate to HRP

by Jiayan Zhu, Ting Li, Shihui Zhang, Xiaomei Zou, Yingchun Zhou, Weiguo Lu, Zhihui Liu, Tao Deng and Fang Liu

Chemosensors 2023, 11(2), 152; https://doi.org/10.3390/chemosensors11020152 - 20 Feb 2023

Cited by 4 | Viewed by 2251

Abstract

Horseradish peroxidase (HRP) combined with its fluorescence substrates is attracting increasing attention for biochemical analysis. Amplex red is the most widely used fluorescence substrate to HRP; however, it suffers from some drawbacks, such as nonspecific responsiveness toward carboxylesterases. Discovering a new small molecular [...] Read more.

Horseradish peroxidase (HRP) combined with its fluorescence substrates is attracting increasing attention for biochemical analysis. Amplex red is the most widely used fluorescence substrate to HRP; however, it suffers from some drawbacks, such as nonspecific responsiveness toward carboxylesterases. Discovering a new small molecular fluorescence substrate with improved sensitivity and selectivity for HRP is thus desired. Herein, three dihydrofluorescein derivatives (DCFHs) are presented to serve as HRP substrates through fluorescence turn-on methods. The most promising one, 2,7-dichloro-9-(2-(hydroxymethyl)phenyl)-9H-xanthene-3,6-diol (DCFH-1), exhibited excellent sensitivity in the detection of HRP. Moreover, DCFH-1 does not respond to carboxylesterase, thus holding advantages over Amplex red. In the further study, the detection reagent in the commercial ELISA kits was replaced with DCFH-1 to establish a new fluorescence ELISA, which works very well in the quantification of inflammatory cytokine biomarkers from in vitro models. Full article

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11 pages, 2579 KiB

Open AccessArticle

Continuous Glucose Monitoring in Hypoxic Environments Based on Water Splitting-Assisted Electrocatalysis

by Lanjie Lei, Chengtao Xu, Xing Dong, Biao Ma, Yichen Chen, Qing Hao, Chao Zhao and Hong Liu

Chemosensors 2023, 11(2), 149; https://doi.org/10.3390/chemosensors11020149 - 18 Feb 2023

Cited by 1 | Viewed by 3247

Abstract

Conventional enzyme-based continuous glucose sensors in interstitial fluid usually rely on dissolved oxygen as the electron-transfer mediator to bring electrons from oxidase to electrode while generating hydrogen peroxide. This may lead to several problems. First, the sensor may provide biased detection results owing [...] Read more.

Conventional enzyme-based continuous glucose sensors in interstitial fluid usually rely on dissolved oxygen as the electron-transfer mediator to bring electrons from oxidase to electrode while generating hydrogen peroxide. This may lead to several problems. First, the sensor may provide biased detection results owing to fluctuation of oxygen in interstitial fluid. Second, the polymer coatings that regulate the glucose/oxygen ratio can affect the dynamic response of the sensor. Third, the glucose oxidation reaction continuously produces corrosive hydrogen peroxide, which may compromise the long-term stability of the sensor. Here, we introduce an oxygen-independent nonenzymatic glucose sensor based on water splitting-assisted electrocatalysis for continuous glucose monitoring. For the water splitting reaction (i.e., hydrogen evolution reaction), a negative pretreatment potential is applied to produce a localized alkaline condition at the surface of the working electrode for subsequent nonenzymatic electrocatalytic oxidation of glucose. The reaction process does not require the participation of oxygen; therefore, the problems caused by oxygen can be avoided. The nonenzymatic sensor exhibits acceptable sensitivity, reliability, and biocompatibility for continuous glucose monitoring in hypoxic environments, as shown by the in vitro and in vivo measurements. Therefore, we believe that it is a promising technique for continuous glucose monitoring, especially for clinically hypoxic patients. Full article

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23 pages, 4368 KiB

Open AccessEditor’s ChoiceReview

Engineering Rational SERS Nanotags for Parallel Detection of Multiple Cancer Circulating Biomarkers

by Zhipeng Zhang, Rui Guan, Junrong Li and Yao Sun

Chemosensors 2023, 11(2), 110; https://doi.org/10.3390/chemosensors11020110 - 3 Feb 2023

Cited by 16 | Viewed by 3648

Abstract

Precision cancer medicine necessitates a personalized treatment plan for each individual patient. Given cancer’s heterogeneity and dynamic nature, the plot of patient-specific signatures composed of multiple cancer circulating biomarkers is useful to reveal the complete tumor landscape for guiding precision medicine. As an [...] Read more.

Precision cancer medicine necessitates a personalized treatment plan for each individual patient. Given cancer’s heterogeneity and dynamic nature, the plot of patient-specific signatures composed of multiple cancer circulating biomarkers is useful to reveal the complete tumor landscape for guiding precision medicine. As an emerging new technology, surface-enhanced Raman scattering (SERS) shows the intrinsic advantage of performing multiplexed detection with the extremely narrow Raman spectral line widths. In this review, we first discuss the design principle of SERS nanotags to enable the detection of multiple circulating biomarkers, highlighting the important roles of plasmonic nanostructures and triple bond-modulated Raman reporters. Following this, we detail the use of isotropic and anisotropic nanostructures as SERS enhancement substrates for amplifying Raman signals in multi-biomarker detection. Furthermore, we present the triple bond-modulated molecules as Raman reporters in SERS nanotags to expand the multiplexing capability for biomarker measurements. Finally, we offer critical insights into the challenges and perspectives of SERS nanotags for cancer diagnosis, particularly from the aspect of future clinical transition. It is expected that this review can facilitate the design of more functional SERS nanotags with high sensitivity and multiplexing capability to assist early and accurate cancer screening. We also believe our review will be of interest in the fields of molecular imaging, biomedicine, and analytical chemistry. Full article

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12 pages, 3572 KiB

Open AccessArticle

WO₃-Nanocrystal-Modified Electrodes for Ultra-Sensitive and Selective Detection of Cadmium (Cd²⁺) Ions

by Ruiqin Gu, Yunong Zhao, Huibing Fu, Qing Huang, Long Li, Zhixiang Hu, Licheng Zhou, Bingbing Chen and Huan Liu

Chemosensors 2023, 11(1), 54; https://doi.org/10.3390/chemosensors11010054 - 7 Jan 2023

Cited by 1 | Viewed by 1669

Abstract

The detection of heavy metal ions is becoming increasingly important for environmental monitoring and personal safety protection. Owing to their large surface area and suitable conductivity, metal oxide semiconductor nanocrystals have been utilized in chemically modified electrodes for the rapid and low-cost detection [...] Read more.

The detection of heavy metal ions is becoming increasingly important for environmental monitoring and personal safety protection. Owing to their large surface area and suitable conductivity, metal oxide semiconductor nanocrystals have been utilized in chemically modified electrodes for the rapid and low-cost detection of heavy metal ions. However, their sensitivity and selectivity for cadmium ion (Cd²⁺) detection still remains a challenge. Here, a method of ultra-sensitive and selective Cd²⁺ detection based on WO₃-nanocrystal-modified electrodes is proposed and demonstrated. Colloidal WO₃ nanocrystals were synthesized via a solvothermal route and then deposited onto a carbon electrode using a spin-coating method, forming the modification layer at room temperature. The WO₃-nanocrystal-modified electrodes exhibit a remarkable signal transduction capability that converts Cd²⁺ adsorption into current output signals. The peak current was linear to the logarithm of the Cd²⁺ concentration from 1 nM to 10,000 nM when measured using the anodic stripping voltammetry method. The selectivity mechanism was studied and attributed to the high adsorption energy of cadmium on WO₃ compared to other heavy metal ions. Employment of WO₃ for a high-performance Cd²⁺-selective electrode opens many opportunities in portable ion-detection applications. Full article

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11 pages, 2803 KiB

Open AccessArticle

Influences of Impurity Gases in Air on Room-Temperature Hydrogen-Sensitive Pt–SnO₂ Composite Nanoceramics: A Case Study of H₂S

by Xilai Lu, Menghan Wu, Yong Huang, Jiannan Song, Yong Liu, Zhiqiao Yan, Feng Chen, Jieting Zhao and Wanping Chen

Chemosensors 2023, 11(1), 31; https://doi.org/10.3390/chemosensors11010031 - 1 Jan 2023

Cited by 6 | Viewed by 2127

Abstract

The slight but cumulative influence of impurity gases in air poses a great threat to the long-term stability of room-temperature gas sensors. Room-temperature hydrogen-sensitive Pt–SnO₂ composite nanoceramics of 5 wt% Pt were prepared through pressing and sintering. The response of a sample [...] Read more.

The slight but cumulative influence of impurity gases in air poses a great threat to the long-term stability of room-temperature gas sensors. Room-temperature hydrogen-sensitive Pt–SnO₂ composite nanoceramics of 5 wt% Pt were prepared through pressing and sintering. The response of a sample was over 10,000 after being exposed to 500 ppm H₂S–20% O₂–N₂ at room temperature, and the room-temperature hydrogen sensing capacity was seriously degraded even for samples that had aged dozens of days since H₂S exposure. Mild heat treatments such as 160 °C for 10 min were found able to fully activate those H₂S-exposed samples. As the peak of S 2p electron was clearly detected in H₂S-exposed samples, it was proposed that for room-temperature hydrogen-sensitive Pt–SnO₂ composite nanoceramics, H₂S exposure induced degradation results from the poisoning of Pt by H₂S deposited on it, which can be removed through a mild heat treatment. Periodic mild heat treatment should be a convenient and effective measure for room-temperature metal oxide gas sensors to achieve long-term stability through preventing the accumulation of impurity gases in air deposited on them. Full article

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2022

Jump to: 2023

27 pages, 26420 KiB

Open AccessReview

Recent Advances in Molecular Fluorescent Probes for CYP450 Sensing and Imaging

by Haiyan Li, Yang Sheng, Wei Li and Lin Yuan

Chemosensors 2022, 10(8), 304; https://doi.org/10.3390/chemosensors10080304 - 2 Aug 2022

Cited by 13 | Viewed by 4431

Abstract

Cytochrome P450 (CYP450) is a major drug-metabolizing enzyme system mainly distributed in liver microsomes and involved in the metabolism of many endogenous substances (such as fatty acids and arachidonic acids), and exogenous compounds (such as drugs, toxicants, carcinogens, and procarcinogens). Due to the [...] Read more.

Cytochrome P450 (CYP450) is a major drug-metabolizing enzyme system mainly distributed in liver microsomes and involved in the metabolism of many endogenous substances (such as fatty acids and arachidonic acids), and exogenous compounds (such as drugs, toxicants, carcinogens, and procarcinogens). Due to the similarity in structures and catalytic functions between CYP450 isoforms, the lack of effective selective detection tools greatly limits the understanding and the research of their respective physiological roles in living organisms. Until now, several small-molecular fluorescent probes have been employed for selective detection and monitoring of CYP450s (Cytochrome P450 enzymes) in vitro or in vivo owing to the tailored properties, biodegradability, and high temporal and spatial resolution imaging in situ. In this review, we summarize the recent advances in fluorescent probes for CYP450s (including CYP1, CYP2, and CYP3 families), and we discuss and focus on their identification mechanisms, general probe design strategies, and bioimaging applications. We also highlight the potential challenges and prospects of designing new generations of fluorescent probes in CYP450 studies, which will further enhance the diversity, practicality, and clinical feasibility of research into CYP450. Full article

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19 pages, 40598 KiB

Open AccessReview

Aptamer-Based Sensors for Thrombin Detection Application

by Hongzhi Sun, Nannan Wang, Lin Zhang, Hongmin Meng and Zhaohui Li

Chemosensors 2022, 10(7), 255; https://doi.org/10.3390/chemosensors10070255 - 30 Jun 2022

Cited by 14 | Viewed by 4132

Abstract

Thrombin facilitates the aggregation of platelet in hemostatic processes and participates in the regulation of cell signaling. Therefore, the development of thrombin sensors is conducive to comprehending the role of thrombin in the course of a disease. Biosensors based on aptamers screened by [...] Read more.

Thrombin facilitates the aggregation of platelet in hemostatic processes and participates in the regulation of cell signaling. Therefore, the development of thrombin sensors is conducive to comprehending the role of thrombin in the course of a disease. Biosensors based on aptamers screened by SELEX have exhibited superiority for thrombin detection. In this review, we summarized the aptamer-based sensors for thrombin detection which rely on the specific recognitions between thrombin and aptamer. Meanwhile, the unique advantages of different sensors including optical and electrochemical sensors were also highlighted. Especially, these sensors based on electrochemistry have the potential to be miniaturized, and thus have gained comprehensive attention. Furthermore, concerns about aptamer-based sensors for thrombin detection, prospects of the future and promising avenues in this field were also presented. Full article

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