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Search Results (237)

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Keywords = electrochemical transducers

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14 pages, 1765 KiB  
Article
Microfluidic System Based on Flexible Structures for Point-of-Care Device Diagnostics with Electrochemical Detection
by Kasper Marchlewicz, Robert Ziółkowski, Kamil Żukowski, Jakub Krzemiński and Elżbieta Malinowska
Biosensors 2025, 15(8), 483; https://doi.org/10.3390/bios15080483 - 24 Jul 2025
Viewed by 390
Abstract
Infectious diseases poses a growing public health challenge. The COVID-19 pandemic has further emphasized the urgent need for rapid, accessible diagnostics. This study presents the development of an integrated, flexible point-of-care (POC) diagnostic system for the rapid detection of Corynebacterium diphtheriae, the [...] Read more.
Infectious diseases poses a growing public health challenge. The COVID-19 pandemic has further emphasized the urgent need for rapid, accessible diagnostics. This study presents the development of an integrated, flexible point-of-care (POC) diagnostic system for the rapid detection of Corynebacterium diphtheriae, the pathogen responsible for diphtheria. The system comprises a microfluidic polymerase chain reaction (micro-PCR) device and an electrochemical DNA biosensor, both fabricated on flexible substrates. The micro-PCR platform offers rapid DNA amplification overcoming the time limitations of conventional thermocyclers. The biosensor utilizes specific molecular recognition and an electrochemical transducer to detect the amplified DNA fragment, providing a clear and direct indication of the pathogen’s presence. The combined system demonstrates the effective amplification and detection of a gene fragment from a toxic strain of C. diphtheriae, chosen due to its increasing incidence. The design leverages lab-on-a-chip (LOC) and microfluidic technologies to minimize reagent use, reduce cost, and support portability. Key challenges in microsystem design—such as flow control, material selection, and reagent compatibility—were addressed through optimized fabrication techniques and system integration. This work highlights the feasibility of using flexible, integrated microfluidic and biosensor platforms for the rapid, on-site detection of infectious agents. The modular and scalable nature of the system suggests potential for adaptation to a wide range of pathogens, supporting broader applications in global health diagnostics. The approach provides a promising foundation for next-generation POC diagnostic tools. Full article
(This article belongs to the Special Issue Microfluidics for Sample Pretreatment)
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63 pages, 4971 KiB  
Review
Electrochemical Nanosensors Applied to the Assay of Some Food Components—A Review
by Aurelia Magdalena Pisoschi, Florin Iordache, Loredana Stanca, Petronela Mihaela Rosu, Nicoleta Ciocirlie, Ovidiu Ionut Geicu, Liviu Bilteanu and Andreea Iren Serban
Chemosensors 2025, 13(8), 272; https://doi.org/10.3390/chemosensors13080272 - 23 Jul 2025
Viewed by 593
Abstract
Nanomaterials’ special features enable their extensive application in chemical and biochemical nanosensors for food assays; food packaging; environmental, medicinal, and pharmaceutical applications; and photoelectronics. The analytical strategies based on novel nanomaterials have proved their pivotal role and increasing interest in the assay of [...] Read more.
Nanomaterials’ special features enable their extensive application in chemical and biochemical nanosensors for food assays; food packaging; environmental, medicinal, and pharmaceutical applications; and photoelectronics. The analytical strategies based on novel nanomaterials have proved their pivotal role and increasing interest in the assay of key food components. The choice of transducer is pivotal for promoting the performance of electrochemical sensors. Electrochemical nano-transducers provide a large active surface area, enabling improved sensitivity, specificity, fast assay, precision, accuracy, and reproducibility, over the analytical range of interest, when compared to traditional sensors. Synthetic routes encompass physical techniques in general based on top–down approaches, chemical methods mainly relying on bottom–up approaches, or green technologies. Hybrid techniques such as electrochemical pathways or photochemical reduction are also applied. Electrochemical nanocomposite sensors relying on conducting polymers are amenable to performance improvement, achieved by integrating redox mediators, conductive hydrogels, and molecular imprinting polymers. Carbon-based or metal-based nanoparticles are used in combination with ionic liquids, enhancing conductivity and electron transfer. The composites may be prepared using a plethora of combinations of carbon-based, metal-based, or organic-based nanomaterials, promoting a high electrocatalytic response, and can accommodate biorecognition elements for increased specificity. Nanomaterials can function as pivotal components in electrochemical (bio)sensors applied to food assays, aiming at the analysis of bioactives, nutrients, food additives, and contaminants. Given the broad range of transducer types, detection modes, and targeted analytes, it is important to discuss the analytical performance and applicability of such nanosensors. Full article
(This article belongs to the Special Issue Electrochemical Sensor for Food Analysis)
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20 pages, 1471 KiB  
Article
A New Approach for Interferent-Free Amperometric Biosensor Production Based on All-Electrochemically Assisted Procedures
by Rosanna Ciriello, Maria Assunta Acquavia, Giuliana Bianco, Angela Di Capua and Antonio Guerrieri
Biosensors 2025, 15(8), 470; https://doi.org/10.3390/bios15080470 - 22 Jul 2025
Viewed by 299
Abstract
A new approach in amperometric enzyme electrodes production based on all-electrochemically assisted procedures will be described. Enzyme (glucose oxidase) immobilization was performed by in situ co-crosslinking of enzyme molecules through electrophoretic protein deposition, assuring enzyme immobilization exclusively onto the transducer surface (Pt electrode). [...] Read more.
A new approach in amperometric enzyme electrodes production based on all-electrochemically assisted procedures will be described. Enzyme (glucose oxidase) immobilization was performed by in situ co-crosslinking of enzyme molecules through electrophoretic protein deposition, assuring enzyme immobilization exclusively onto the transducer surface (Pt electrode). Analogously, the poor selectivity of the transducer was dramatically improved by the electrosynthesis of non-conducting polymers with built-in permselectivity, permitting the formation of a thin permselective film onto the transducer surface, able to reject common interferents usually found in real samples. Since both approaches required a proper and distinct electrochemical perturbation (a pulsed current sequence for electrophoretic protein deposition and cyclic voltammetry for the electrosynthesis of non-conducting polymers), an appropriate coupling of the two all-electrochemical approaches was assured by a thorough study of the likely combinations of the electrosynthesis of permselective polymers with enzyme immobilization by electrophoretic protein deposition and by the use of several electrosynthesized polymers. For each investigated combination and for each polymer, the analytical performances and the rejection capabilities of the resulting biosensor were acquired so to gain information about their sensing abilities eventually in real sample analysis. This study shows that the proper coupling of the two all-electrochemical approaches and the appropriate choice of the electrosynthesized, permselective polymer permits the easy fabrication of novel glucose oxidase biosensors with good analytical performance and low bias in glucose measurement from typical interferent in serum. This novel approach, resembling classical electroplating procedures, is expected to allow all the advantages expected from such procedures like an easy preparation biosensor, a bi-dimensional control of enzyme immobilization and thickness, interferent- and fouling-free transduction of the electrodic sensor and, last but not the least, possibility of miniaturization of the biosensing device. Full article
(This article belongs to the Special Issue Novel Designs and Applications for Electrochemical Biosensors)
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16 pages, 2441 KiB  
Article
Phosphonium Salt-Functionalized β-Cyclodextrin Film for Ultrasensitive and Selective Electrochemical Impedance Spectroscopy Detection of Perchlorate in Drinking Water
by Zeineb Baatout, Achref Jebnouni, Nawfel Sakly, Safa Teka, Nuzaiha Mohamed, Sayda Osman, Raoudha Soury, Mabrouka El Oudi, Salman Hamdan Alsaqri, Nejmeddine Smida Jaballah and Mustapha Majdoub
Polymers 2025, 17(14), 1937; https://doi.org/10.3390/polym17141937 - 15 Jul 2025
Viewed by 401
Abstract
This work represents the first use of a phosphonium salt-functionalized β-Cyclodextrin polymer (β-CDP) as a highly selective sensing membrane for monitoring the safety of drinking water against perchlorate ions (ClO4) using electrochemical impedance spectroscopy (EIS). Structural confirmation via 1H [...] Read more.
This work represents the first use of a phosphonium salt-functionalized β-Cyclodextrin polymer (β-CDP) as a highly selective sensing membrane for monitoring the safety of drinking water against perchlorate ions (ClO4) using electrochemical impedance spectroscopy (EIS). Structural confirmation via 1H NMR, 13C NMR, 31P NMR, and FT-IR spectroscopies combined with AFM and contact angle measurements demonstrate how the enhanced solubility of modified cyclodextrin improves thin film quality. The innovation lies in the synergistic combination of two detection mechanisms: the “Host-Guest” inclusion in the cyclodextrin cavity and anionic exchange between the bromide ions of the phosphonium groups and perchlorate anions. Under optimized functionalization conditions, EIS reveals high sensitivity and selectivity, achieving a record-low detection limit (LOD) of ~10−12 M and a wide linear range of detection (10−11 M–10−4 M). Sensing mechanisms at the functionalized transducer interfaces are examined through numerical fitting of Cole-Cole impedance spectra via a single relaxation equivalent circuit. Real water sample analysis confirms the sensor’s practical applicability, with recoveries between 96.9% and 109.8% and RSDs of 2.4–4.8%. Finally, a comparative study with reported membrane sensors shows that β-CDP offers superior performance, wider range, higher sensitivity, lower LOD, and simpler synthesis. Full article
(This article belongs to the Special Issue Development of Polymer Materials as Functional Coatings)
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22 pages, 2532 KiB  
Review
A Review on Xanthine Oxidase-Based Electrochemical Biosensors: Food Safety and Quality Control Applications
by Totka Dodevska
Chemosensors 2025, 13(5), 159; https://doi.org/10.3390/chemosensors13050159 - 1 May 2025
Viewed by 997
Abstract
Electrochemical biosensors are integrated bio-receptor–transducer devices that convert specific biological interactions into measurable electrical signals. Over the past decade, the use of novel nanomaterials, advanced enzyme immobilization techniques, and enhanced sensor architectures have been extensively studied, yielding significant progress in the design of [...] Read more.
Electrochemical biosensors are integrated bio-receptor–transducer devices that convert specific biological interactions into measurable electrical signals. Over the past decade, the use of novel nanomaterials, advanced enzyme immobilization techniques, and enhanced sensor architectures have been extensively studied, yielding significant progress in the design of highly sensitive, rapid, and reliable electrochemical biosensors. In the modern food industry various types of electrochemical biosensors are used, playing essential roles in the processes monitoring and optimization. This review highlights the strategies implemented to improve the analytical performance of electrochemical enzyme biosensors based on xanthine oxidase (XOx) for the quantitative detection of xanthine (X) and hypoxanthine (Hx), analytes relevant to the field of food quality control. The article covers recent developments (mainly original studies reported from 2010 to date) in the substrate materials, different electrode designs, working principles, advantages, limitations, and applications of XOx biosensors for meat freshness assessment. The article is meant to be a valuable resource that provides insights for improving design for the next generation bio-electroanalytical platforms to ensure food safety. Full article
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17 pages, 56423 KiB  
Article
A Cost-Effective and Rapid Manufacturing Approach for Electrochemical Transducers with Magnetic Beads for Biosensing
by Milica Govedarica, Ivana Milosevic, Vesna Jankovic, Radmila Mitrovic, Ivana Kundacina, Ivan Nastasijevic and Vasa Radonic
Micromachines 2025, 16(3), 343; https://doi.org/10.3390/mi16030343 - 17 Mar 2025
Cited by 1 | Viewed by 1053
Abstract
Biosensors as advanced analytical tools have found various applications in food safety, healthcare, and environmental monitoring in rapid and specific detection of target analytes in small liquid samples. Up to now, planar electrochemical electrodes have shown the highest potential for biosensor applications due [...] Read more.
Biosensors as advanced analytical tools have found various applications in food safety, healthcare, and environmental monitoring in rapid and specific detection of target analytes in small liquid samples. Up to now, planar electrochemical electrodes have shown the highest potential for biosensor applications due to their simple and compact construction and cost-effectiveness. Although a number of commercially available electrodes, manufactured from various materials on different substrates, can be found on the market, their high costs for single use and low reproducibility persist as major drawbacks. In this study, we present an innovative, cost-effective approach for the rapid fabrication of electrodes that combines lamination of 24-karat gold leaves with low-cost polyvinyl chloride adhesive sheets followed by laser ablation. Laser ablation enables the creation of electrodes with customizable geometries and patterns with microlevel resolutions. The developed electrodes are characterized by cyclic voltammetry and electrochemical impedance spectroscopy, scanning electronic microscopy, and 3D profiling. To demonstrate the manufacturing and biosensing potential, different geometries and shapes of electrodes were realized as the electrochemical transducing platform and applied for the realization of magnetic bead (MB)-labeled biosensors for quantitative detection of food-borne pathogens of Salmonella typhimurium (S. typhimurium) and Listeria monocytogenes (L. monocytogenes). Full article
(This article belongs to the Section D3: 3D Printing and Additive Manufacturing)
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16 pages, 3089 KiB  
Article
Electrochemical Pretreatment and Functionalization of Pencil Graphite Electrodes for Enhanced Transducer Performance in Biosensing
by Rafael Mendes Coelho, Alexandre Rafael Moraes da Silva, Geycson Figueiredo Dias, Danilo Bretas de Oliveira, Arnaldo César Pereira, Diego Leoni Franco and Lucas Franco Ferreira
Chemosensors 2025, 13(3), 84; https://doi.org/10.3390/chemosensors13030084 - 2 Mar 2025
Viewed by 1016
Abstract
This study aimed to optimize the electrochemical pretreatment and functionalization of pencil graphite electrodes (PGEs) for the performance evaluation of a transducer applied in initial studies in the development of an immunosensor for vaccinia virus (VACV) detection. The effects of the applied potential, [...] Read more.
This study aimed to optimize the electrochemical pretreatment and functionalization of pencil graphite electrodes (PGEs) for the performance evaluation of a transducer applied in initial studies in the development of an immunosensor for vaccinia virus (VACV) detection. The effects of the applied potential, duration, and supporting electrolyte type and concentration on PGE activation were investigated. Functionalization using a polymeric film derived from 2-hydroxybenzamide (2-HXB) was optimized by varying the applied potential, deposition time, and monomer concentration. Optimal activation conditions were found to be +0.90 V in 0.02 M of H2SO4 for 300 s, promoting the formation of hydrogenated groups and increasing electrode wettability. For electropolymerization, +1.20 V for 300 s with a 2-HXB concentration of 2.50 mM provided the best results, ensuring proper film formation and adhesion. Scanning electron microscopy revealed a rough, sheet-like surface on the polished PGE, while energy dispersive spectroscopy confirmed poly(2-HXB) adsorption through increased oxygen and nitrogen content on the functionalized electrode. The optimized pretreatment and functionalization conditions significantly influenced the response of the transducer used for VACV detection, demonstrating its crucial role in device development. These findings contribute to the advancement of inexpensive and effective electrochemical transducers and highlight the importance of pretreatment and modification of PGEs in biosensing applications. Full article
(This article belongs to the Special Issue Advanced Biosensors for Diagnostic Applications)
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36 pages, 10799 KiB  
Review
An In-Depth Review of Molecularly Imprinted Electrochemical Sensors as an Innovative Analytical Tool in Water Quality Monitoring: Architecture, Principles, Fabrication, and Applications
by Mbuyamba Divin Mukendi, Oluseyi Sikiru Salami and Nomvano Mketo
Micromachines 2025, 16(3), 251; https://doi.org/10.3390/mi16030251 - 23 Feb 2025
Cited by 1 | Viewed by 2269
Abstract
Molecularly imprinted electrochemical sensors (MI-ECSs) are a significant advancement in analytical techniques, especially for water quality monitoring (WQM). These sensors utilize molecular imprinting to create polymer matrices that exhibit high specificity and affinity for target analytes. MI-ECSs integrate molecularly imprinted polymers (MIPs) with [...] Read more.
Molecularly imprinted electrochemical sensors (MI-ECSs) are a significant advancement in analytical techniques, especially for water quality monitoring (WQM). These sensors utilize molecular imprinting to create polymer matrices that exhibit high specificity and affinity for target analytes. MI-ECSs integrate molecularly imprinted polymers (MIPs) with electrochemical transducers (ECTs), enabling the selective recognition and quantification of contaminants. Their design features template-shaped cavities in the polymer that mimic the functional groups, shapes, and sizes of target analytes, resulting in enhanced binding interactions and improved sensor performance in complex water environments. The fabrication of MI-ECSs involves selecting suitable monomeric units (monomers) and crosslinkers, using a target analyte as a template, polymerizing, and then removing the template to expose the imprinted sites. Advanced methodologies, such as electropolymerization and surface imprinting, are used to enhance their sensitivity and reproducibility. MI-ECSs offer considerable benefits, including high selectivity, low detection limits, rapid response times, and the potential for miniaturization and portability. They effectively assess and detect contaminants, like (toxic) heavy metals (HMs), pesticides, pharmaceuticals, and pathogens, in water systems. Their ability for real-time monitoring makes them essential for ensuring water safety and adhering to regulations. This paper reviews the architecture, principles, and fabrication processes of MI-ECSs as innovative strategies in WQM and their application in detecting emerging contaminants and toxicants (ECs and Ts) across various matrices. These ECs and Ts include organic, inorganic, and biological contaminants, which are mainly anthropogenic in origin and have the potential to pollute water systems. Regarding this, ongoing advancements in MI-ECS technology are expected to further enhance the analytical capabilities and performances of MI-ECSs to broaden their applications in real-time WQM and environmental monitoring. Full article
(This article belongs to the Special Issue Electrochemical Sensors: Design, Fabrication and Applications)
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39 pages, 2817 KiB  
Review
Advances in Biosensor Applications of Metal/Metal-Oxide Nanoscale Materials
by Md Abdus Subhan, Newton Neogi, Kristi Priya Choudhury and Mohammed M. Rahman
Chemosensors 2025, 13(2), 49; https://doi.org/10.3390/chemosensors13020049 - 3 Feb 2025
Cited by 4 | Viewed by 3059
Abstract
Biosensing shows promise in detecting cancer, renal disease, and other illnesses. Depending on their transducing processes, varieties of biosensors can be divided into electrochemical, optical, piezoelectric, and thermal biosensors. Advancements in material production techniques, enzyme/protein designing, and immobilization/conjugation approaches can yield novel nanoparticles [...] Read more.
Biosensing shows promise in detecting cancer, renal disease, and other illnesses. Depending on their transducing processes, varieties of biosensors can be divided into electrochemical, optical, piezoelectric, and thermal biosensors. Advancements in material production techniques, enzyme/protein designing, and immobilization/conjugation approaches can yield novel nanoparticles with further developed functionality. Research in cutting-edge biosensing with multifunctional nanomaterials, and the advancement of practical biochip plans utilizing nano-based sensing material, are of current interest. The miniaturization of electronic devices has enabled the growth of ultracompact, compassionate, rapid, and low-cost sensing technologies. Some sensors can recognize analytes at the molecule, particle, and single biological cell levels. Nanomaterial-based sensors, which can be used for biosensing quickly and precisely, can replace toxic materials in real-time diagnostics. Many metal-based NPs and nanocomposites are favorable for biosensing. Through direct and indirect labeling, metal-oxide NPs are extensively employed in detecting metabolic disorders, such as cancer, diabetes, and kidney-disease biomarkers based on electrochemical, optical, and magnetic readouts. The present review focused on recent developments across multiple biosensing modalities using metal/metal-oxide-based NPs; in particular, we highlighted the specific advancements of biosensing of key nanomaterials like ZnO, CeO2, and TiO2 and their applications in disease diagnostics and environmental monitoring. For example, ZnO-based biosensors recognize uric acid, glucose, cholesterol, dopamine, and DNA; TiO2 is utilized for SARS-CoV-19; and CeO2 for glucose detection. Full article
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12 pages, 3482 KiB  
Article
Driving Rotational Circulation in a Microfluidic Chamber Using Dual Focused Surface-Acoustic-Wave Beams
by Jin-Chen Hsu and Kai-Li Liao
Micromachines 2025, 16(2), 140; https://doi.org/10.3390/mi16020140 - 25 Jan 2025
Viewed by 1218
Abstract
In this paper, enhanced rotational circulation in a circular microfluidic chamber driven by dual focused surface-acoustic-wave (SAW) beams is presented. To characterize the resonant frequency and focusing effect, we simulate the focused SAW field excited by an arc-shaped interdigital transducer patterned on a [...] Read more.
In this paper, enhanced rotational circulation in a circular microfluidic chamber driven by dual focused surface-acoustic-wave (SAW) beams is presented. To characterize the resonant frequency and focusing effect, we simulate the focused SAW field excited by an arc-shaped interdigital transducer patterned on a 128°Y-cut lithium-niobate (LiNbO3) substrate using a finite element method. A full three-dimensional perturbation model of the combined system of the microfluidic chamber and the SAW device is conducted to obtain the acoustic pressure and acoustic streaming fields, which show rotational acoustic pressure and encircling streaming resulted in the chamber. Accordingly, the SAW acoustofluidic system is realized using microfabrication techniques and applied to perform acoustophoresis experiments on submicron particles suspending in the microfluidic chamber. The result verifies the rotational circulation motion of the streaming flow, which is attributed to enhanced angular momentum flux injection and Eckart streaming effect through the dual focused SAW beams. Our results should be of importance in driving particle circulation and enhancing mass transfer in chamber embedded microfluidic channels, which may have promising applications in accelerating bioparticle or cell reactions and fusion, enhancing biochemical and electrochemical sensing, and efficient microfluidic mixing. Full article
(This article belongs to the Special Issue Surface and Bulk Acoustic Wave Devices)
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15 pages, 4798 KiB  
Article
Carboxylated Graphene: An Innovative Approach to Enhanced IgA-SARS-CoV-2 Electrochemical Biosensing
by Luciana de Souza Freire, Ariamna María Dip Gandarilla, Yonny Romaguera Barcelay, Camila Macena Ruzo, Barbara Batista Salgado, Ana P. M. Tavares, Francisco Xavier Nobre, Julio Nino de Souza Neto, Spartaco Astolfi-Filho, Ștefan Țălu, Pritesh Lalwani, Niranjan Patra and Walter Ricardo Brito
Biosensors 2025, 15(1), 34; https://doi.org/10.3390/bios15010034 - 9 Jan 2025
Viewed by 1215
Abstract
Biosensors harness biological materials as receptors linked to transducers, enabling the capture and transformation of primary biorecognition signals into measurable outputs. This study presents a novel carboxylation method for synthesizing carboxylated graphene (CG) under acidic conditions, enhancing biosensing capabilities. The characterization of the [...] Read more.
Biosensors harness biological materials as receptors linked to transducers, enabling the capture and transformation of primary biorecognition signals into measurable outputs. This study presents a novel carboxylation method for synthesizing carboxylated graphene (CG) under acidic conditions, enhancing biosensing capabilities. The characterization of the CG was performed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, thermogravimetric analysis (TGA), and X-ray diffraction (XRD). We modified screen-printed carbon electrodes (SPCEs) with CG to immobilize the SARS-CoV-2 N-protein, facilitating targeted detection of IgA antibodies (IgA-SARS-CoV-2). The analytical performance was assessed via electrochemical techniques such as cyclic voltammetry and electrochemical impedance spectroscopy, confirming CG synthesis effectiveness and biosensor functionality. The developed biosensor efficiently detects IgA-SARS-CoV-2 across a dilution range of 1:1000 to 1:200 v/v in a phosphate-buffered saline (PBS) solution, with a limit of detection calculated at 1:1601 v/v. This device shows considerable potential because of its fast response time, miniaturized design facilitated by SPCEs, reduced sample volume requirements, high sensitivity and specificity, low detection limits, and signal enhancement achieved through nanomaterial integration. Full article
(This article belongs to the Special Issue Nanomaterial-Enhanced Biosensing for Point-of-Care Diagnostics)
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14 pages, 2747 KiB  
Article
Electrochemical Magnetic Immunoassay for the Determination of the Fish Allergen β-Parvalbumin
by José Pedro Rocha, Maria Freitas, Dulce Geraldo, Fátima Bento, Cristina Delerue-Matos and Henri P. A. Nouws
Biosensors 2024, 14(12), 639; https://doi.org/10.3390/bios14120639 - 23 Dec 2024
Viewed by 1284
Abstract
β-parvalbumin (β-PV) is the primary fish allergen responsible for most allergic reactions in individuals sensitive to fish. To ensure food safety, a sandwich-based magnetic immunoassay was developed using maleimide-functionalized magnetic beads (NH-MBs). Specific anti-β-PV antibodies were immobilized on these MBs, and a screen-printed [...] Read more.
β-parvalbumin (β-PV) is the primary fish allergen responsible for most allergic reactions in individuals sensitive to fish. To ensure food safety, a sandwich-based magnetic immunoassay was developed using maleimide-functionalized magnetic beads (NH-MBs). Specific anti-β-PV antibodies were immobilized on these MBs, and a screen-printed carbon electrode was employed as the electrochemical transducer. A linear concentration range from 10 to 1000 ng/mL, a limit of detection of 1.8 ng/mL, and a limit of quantification of 7.1 ng/mL were achieved. Nineteen commercial food samples were analyzed to assess the potential of the sensor for routine use in food quality control. Important factors such as protein source and food processing (e.g., boiling, grilling, and frying) and preservation (e.g., in oil, and vacuum) were evaluated. The validated results confer the usefulness of the assay for food quality control. Full article
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16 pages, 5491 KiB  
Article
Point-of-Care Detection of Carcinoembryonic Antigen (CEA) Using a Smartphone-Based, Label-Free Electrochemical Immunosensor with Multilayer CuONPs/CNTs/GO on a Disposable Screen-Printed Electrode
by Supada Khonyoung, Praphatsorn Mangkronkaew, Puttaporn Klayprasert, Chanida Puangpila, Muthukumaran Palanisami, Mani Arivazhagan and Jaroon Jakmunee
Biosensors 2024, 14(12), 600; https://doi.org/10.3390/bios14120600 - 7 Dec 2024
Cited by 2 | Viewed by 2950
Abstract
In order to identify carcinoembryonic antigen (CEA) in serum samples, an innovative smartphone-based, label-free electrochemical immunosensor was created without the need for additional labels or markers. This technology presents a viable method for on-site cancer diagnostics. The novel smartphone-integrated, label-free immunosensing platform was [...] Read more.
In order to identify carcinoembryonic antigen (CEA) in serum samples, an innovative smartphone-based, label-free electrochemical immunosensor was created without the need for additional labels or markers. This technology presents a viable method for on-site cancer diagnostics. The novel smartphone-integrated, label-free immunosensing platform was constructed by nanostructured materials that utilize the layer-by-layer (LBL) assembly technique, allowing for meticulous control over the interface. Detection relies on direct interactions without extra tagging agents, where ordered graphene oxide (GO), carbon nanotubes (CNTs), and copper oxide nanoparticles (CuONPs) were sequentially deposited onto a screen-printed carbon electrode (SPCE), designated as CuONPs/CNTs/GO/SPCE. This significantly amplifies the electrochemical signal, allowing for the detection of low concentrations of target molecules of CEA. The LBL approach enables the precise construction of multi-layered structures on the sensor surface, enhancing their activity and optimizing the electrochemical performance for CEA detection. These nanostructured materials serve as efficient carriers to significantly increase the surface area, conductivity, and structural support for antibody loading, thus improving the sensitivity of detection. The detection of carcinoembryonic antigen (CEA) in this electrochemical immunosensing transducer is based on a decrease in the current response of the [Fe(CN)6]3−/4− redox probes, which occurs in proportion to the amount of the immunocomplex formed on the sensor surface. Under the optimized conditions, the immunosensor exhibited good detection of CEA with a linear range of 0.1–5.0 ng mL−1 and a low detection limit of 0.08 ng mL−1. This label-free detection approach, based on signal suppression due to immunocomplex formation, is highly sensitive and efficient for measuring CEA levels in serum samples, with higher recovery ranges of 101% to 112%, enabling early cancer diagnosis. The immunosensor was successfully applied to determine CEA in serum samples. This immunosensor has several advantages, including simple fabrication, portability, rapid analysis, high selectivity and sensitivity, and good reproducibility with long-term stability over 21 days. Therefore, it has the potential for point-of-care diagnosis of lung cancer. Full article
(This article belongs to the Special Issue Immunosensors: Design and Applications)
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24 pages, 7527 KiB  
Review
CRISPR–Cas Systems Associated with Electrolyte-Gated Graphene-Based Transistors: How They Work and How to Combine Them
by Pierre Guermonprez, Pierre Nioche, Louis Renaud, Nicolas Battaglini, Sébastien Sanaur, Eric Krejci and Benoît Piro
Biosensors 2024, 14(11), 541; https://doi.org/10.3390/bios14110541 - 7 Nov 2024
Cited by 2 | Viewed by 2472
Abstract
In this review, recent advances in the combination of CRISPR–Cas systems with graphene-based electrolyte-gated transistors are discussed in detail. In the first part, the functioning of CRISPR–Cas systems is briefly explained, as well as the most common ways to convert their molecular activity [...] Read more.
In this review, recent advances in the combination of CRISPR–Cas systems with graphene-based electrolyte-gated transistors are discussed in detail. In the first part, the functioning of CRISPR–Cas systems is briefly explained, as well as the most common ways to convert their molecular activity into measurable signals. Other than optical means, conventional electrochemical transducers are also developed. However, it seems that the incorporation of CRISPR/Cas systems into transistor devices could be extremely powerful, as the former provides molecular amplification, while the latter provides electrical amplification; combined, the two could help to advance in terms of sensitivity and compete with conventional PCR assays. Today, organic transistors suffer from poor stability in biological media, whereas graphene materials perform better by being extremely sensitive to their chemical environment and being stable. The need for fast and inexpensive sensors to detect viral RNA arose on the occasion of the COVID-19 crisis, but many other RNA viruses are of interest, such as dengue, hepatitis C, hepatitis E, West Nile fever, Ebola, and polio, for which detection means are needed. Full article
(This article belongs to the Special Issue Feature Paper in Biosensor and Bioelectronic Devices 2024)
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25 pages, 5952 KiB  
Review
The Evolution of Illicit-Drug Detection: From Conventional Approaches to Cutting-Edge Immunosensors—A Comprehensive Review
by Nigar Anzar, Shariq Suleman, Yashda Singh, Supriya Kumari, Suhel Parvez, Roberto Pilloton and Jagriti Narang
Biosensors 2024, 14(10), 477; https://doi.org/10.3390/bios14100477 - 3 Oct 2024
Cited by 5 | Viewed by 3243
Abstract
The increasing use of illicit drugs has become a major global concern. Illicit drugs interact with the brain and the body altering an individual’s mood and behavior. As the substance-of-abuse (SOA) crisis continues to spread across the world, in order to reduce trafficking [...] Read more.
The increasing use of illicit drugs has become a major global concern. Illicit drugs interact with the brain and the body altering an individual’s mood and behavior. As the substance-of-abuse (SOA) crisis continues to spread across the world, in order to reduce trafficking and unlawful activity, it is important to use point-of-care devices like biosensors. Currently, there are certain conventional detection methods, which include gas chromatography (GC), mass spectrometry (MS), surface ionization, surface-enhanced Raman spectroscopy (SERS), surface plasmon resonance (SPR), electrochemiluminescence (ECL), high-performance liquid chromatography (HPLC), etc., for the detection of abused drugs. These methods have the advantage of high accuracy and sensitivity but are generally laborious, expensive, and require trained operators, along with high sample requirements, and they are not suitable for on-site drug detection scenarios. As a result, there is an urgent need for point-of-care technologies for a variety of drugs that can replace conventional techniques, such as a biosensor, specifically an immunosensor. An immunosensor is an analytical device that integrates an antibody-based recognition element with a transducer to detect specific molecules (antigens). In an immunosensor, the highly selective antigen–antibody interaction is used to identify and quantify the target analyte. The binding event between the antibody and antigen is converted by the transducer into a measurable signal, such as electrical, optical, or electrochemical, which corresponds to the presence and concentration of the analyte in the sample. This paper provides a comprehensive overview of various illicit drugs, the conventional methods employed for their detection, and the advantages of immunosensors over conventional techniques. It highlights the critical need for on-site detection and explores emerging point-of-care testing methods. The paper also outlines future research goals in this field, emphasizing the potential of advanced technologies to enhance the accuracy, efficiency, and convenience of drug detection. Full article
(This article belongs to the Special Issue Feature Paper in Biosensor and Bioelectronic Devices 2024)
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