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One‐dimensional zinc oxide nanomaterials (1DZnO) have emerged as promising, cost‐effective nanoplatforms with adjustable properties suitable for electrochemical and optical biosensing applications. In this work, modifications in the inherent photoluminescent response of 1DZnO are harnessed to develop a novel immunosensor tailored for detecting enteropathogenic Escherichia coli. This nanobiosensor demonstrates a modulation in photoluminescence signal, effectively responsive to analyte concentrations ranging from 1 × 102 to 1 × 108 CFU mL−1, with direct visualization of targeted bacterial cells over 1DZnO structures through scanning electron microscopy. The conceptualization of this nanobiosensor is focused on a real‐time contact strategy that can significantly reduce processing and response times for pathogen detection, prospected for emergency scenarios. With this aim, the detection process unfolds in real time, with a mere 5–10 s interaction time, corroborated by the standard polymerase chain reaction approach. This synergistic validation underscores the reliability and precision of the developed biosensor. Notably, the utility of 1DZnO nanoplatforms extends beyond the realm of enteropathogenic E. coli, as the biosensing performance exhibited here holds promise for analogous applications involving other medically pertinent pathogens. This study paves the way for the broader implementation of 1DZnO‐based biosensors in medical diagnostics, offering rapid, sensitive, and real‐time detection capabilities. [ABSTRACT FROM AUTHOR]

Acute myocardial infarction (AMI) is a major cause of cardiovascular disease‐related death. It is essential for patients with cardiovascular disease to receive an early diagnosis of AMI. The most popular technique for the early detection of AMI is the use of biosensors to monitor the concentration of pertinent biomarkers, such as cardiac troponin I (cTnI), in the blood. The electrochemical detection methods hold great promise because of their simplicity, miniaturization, ease of integration, high sensitivity, and rapid response. The prime motive of this review is to present a comprehensive understanding of the pros and cons of methodologies employed for the electrochemical approaches toward the detection of cTnI. A detailed summary is provided for the immunosensors, aptamer sensors, molecular imprinting sensors, and peptide sensors based on various affinity elements. We enumerate the modified electrode materials for electrochemical sensors as well as popular detection techniques. Furthermore, this paper reviews some recent significant advances in point‐of‐care assays for rapid, accurate detection of cTnI as a smart integrated device for home monitoring. The accumulation of knowledge about these functions will lead to new insights into and concepts for the design of portable miniature sensors for cardiovascular patients at risk of AMI. It is anticipated that the interdisciplinary collaboration can bring more enlightenment to the progress of cardiac biomarkers sensor in the future. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Yun Li,1,2 Zhijie Xu,3 Zijuan Qi,4 Xiaofeng Huang,1,2 Mingyu Li,5 Sijin Liu,1,2 Yuanliang Yan,6 Ming Gao1,2 1State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, People’s Republic of China; 2University of Chinese Academy of Sciences, Beijing, People’s Republic of China; 3Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, People’s Republic of China; 4Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, People’s Republic of China; 5Mudanjiang Medical University, Mu Danjiang, Hei Longjiang, People’s Republic of China; 6Department of Pharmacy, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, People’s Republic of ChinaCorrespondence: Yuanliang Yan, Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, People’s Republic of China, Email yanyuanliang@csu.edu.cn Ming Gao, State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, People’s Republic of China, Email minggao@rcees.ac.cnAbstract: Recent advances in tumor immunotherapy have highlighted the pivotal role of carbon nanomaterials, such as carbon dots, graphene quantum dots, and carbon nanotubes. This review examines the unique benefits of these materials in cancer treatment, focusing on their mechanisms of action within immunotherapy. These include applications in immunoregulation, recognition, and enhancement. We explore how these nanomaterials when combined with specific biomolecules, can form immunosensors. These sensors are engineered for highly sensitive and specific detection of tumor markers, offering crucial support for early diagnosis and timely therapeutic interventions. This review also addresses significant challenges facing carbon nanomaterials in clinical settings, such as issues related to long-term biocompatibility and the hurdles of clinical translation. These challenges require extensive ongoing research and discussion. This review is of both theoretical and practical importance, aiming to promote using carbon nanomaterials in tumor immunotherapy, potentially transforming clinical outcomes and enhancing patient care.Keywords: carbon nanoparticles, immune cell, tumor immunotherapy, drug delivery, immunosensors

The standard laboratory methods used to detect Salmonella are time-consuming, leading to unavoidable delays, which can be costly (e.g., food checks at customs) or even dangerous when quick alarms are needed (e.g., for potential outbreaks). To address this problem, we propose a rapid two-step colorimetric immunoassay. In the first step, gold nanoparticles interact with the sample, while in the second step, an optimized amount of saline solution is added to induce cluster formation among the unbound nanoparticles, providing a color change that inversely correlates with the bacteria concentration. The nanoparticles were functionalized using a technique based on UV activation of the antibodies, resulting in oriented antibodies with antigen-binding regions in the proximity of the surface. While a color change can be observed with the naked eye at relatively higher bacterial concentrations, a more quantitative approach based on UV–visible spectrum measurements allowed us to achieve a limit of detection of 1 cfu/mL in chicken samples. The test can be completed in 15 min and performed on-site, paving the way for widespread applications of our biosensor in the field of food safety. [ABSTRACT FROM AUTHOR]

Electrochemical immunosensors have emerged in the last years as outstanding analytical systems for the detection of analytes of clinical interest. As alternative to the traditional enzymatic labels, the use of nanoparticles and especially bimetallic ones has gained increased attention thanks to their advantages related to the higher simplicity, stability and sensitivity offered. Main routes for the detection of such nanoparticle labels are based on i) dissolution of the nanoparticle into the corresponding metal ions followed by voltammetric detection; ii) taking advantage of the electrocatalytic effect of the metals towards secondary reactions; and iii) taking advantage of their electrochemiluminescence properties. [ABSTRACT FROM AUTHOR]

Tetrodotoxin (TTX) is a highly potent and widely distributed ion-channel marine neurotoxin; it has no specific antidote and poses a great risk to human health. Therefore, detecting and quantifying TTX to effectively implement prevention strategies is important for food safety. The development of novel and highly sensitive, highly specific, rapid, and simple techniques for trace TTX detection has attracted widespread attention. This review summarizes the latest advances in the detection and quantitative analysis of TTX, covering detection methods based on biological and cellular sensors, immunoassays and immunosensors, aptamers, and liquid chromatography-mass spectrometry. It further discusses the advantages and applications of various detection technologies developed for TTX and focuses on the frontier areas and development directions of TTX detection, providing relevant information for further investigations. [ABSTRACT FROM AUTHOR]

The hepatitis B virus (HBV) causes acute and chronic hepatitis. Around 250 million people worldwide have chronic HBV. When hepatitis B surface antigens (HBsAgs) are found in the blood, the person is infected. Using a compassionate and exact approach is critical and beneficial. Immunosensor signal amplification is one of the most effective specific diagnostic procedures in clinical, biological, and environmental settings. In this study, HBsAg was detected by immunoassay using MoFeNiS, MoCoFeS, MoNiCoS, and FeCoNiS nanocomposites coupled to the secondary antibody. Nanocomposites established with negative surface charge, high surface to volume and porosity ratio, magnetic and electrical properties, simple and inexpensive synthesis, and easy dispersion in deionized water, among other qualities. Electrostatic adsorption between the negative surface charges of the nanocomposites and the positive charge established on the surface of antibodies was used to connect these nanocomposites to the anti-HBsAg antibody. Also to ensure the correct connection between the nanocomposites and antibodies, several tests including DLS, zeta potential, UV–Vis, FTIR, and fluorescence spectroscopy were performed before and after the modifications. Finally, the results of this study demonstrated the successful manufacture of safety sensors using these modified nanocomposites, which can detect HBsAg at concentrations ranging from 5.65 pg/mL to 5.65 ng/mL through ELISA immune sandwich absorption system. [ABSTRACT FROM AUTHOR]

One‐dimensional zinc oxide nanomaterials (1DZnO) have emerged as promising, cost‐effective nanoplatforms with adjustable properties suitable for electrochemical and optical biosensing applications. In this work, modifications in the inherent photoluminescent response of 1DZnO are harnessed to develop a novel immunosensor tailored for detecting enteropathogenic Escherichia coli. This nanobiosensor demonstrates a modulation in photoluminescence signal, effectively responsive to analyte concentrations ranging from 1 × 102 to 1 × 108 CFU mL−1, with direct visualization of targeted bacterial cells over 1DZnO structures through scanning electron microscopy. The conceptualization of this nanobiosensor is focused on a real‐time contact strategy that can significantly reduce processing and response times for pathogen detection, prospected for emergency scenarios. With this aim, the detection process unfolds in real time, with a mere 5–10 s interaction time, corroborated by the standard polymerase chain reaction approach. This synergistic validation underscores the reliability and precision of the developed biosensor. Notably, the utility of 1DZnO nanoplatforms extends beyond the realm of enteropathogenic E. coli, as the biosensing performance exhibited here holds promise for analogous applications involving other medically pertinent pathogens. This study paves the way for the broader implementation of 1DZnO‐based biosensors in medical diagnostics, offering rapid, sensitive, and real‐time detection capabilities.

Abstract Acute myocardial infarction (AMI) is a major cause of cardiovascular disease‐related death. It is essential for patients with cardiovascular disease to receive an early diagnosis of AMI. The most popular technique for the early detection of AMI is the use of biosensors to monitor the concentration of pertinent biomarkers, such as cardiac troponin I (cTnI), in the blood. The electrochemical detection methods hold great promise because of their simplicity, miniaturization, ease of integration, high sensitivity, and rapid response. The prime motive of this review is to present a comprehensive understanding of the pros and cons of methodologies employed for the electrochemical approaches toward the detection of cTnI. A detailed summary is provided for the immunosensors, aptamer sensors, molecular imprinting sensors, and peptide sensors based on various affinity elements. We enumerate the modified electrode materials for electrochemical sensors as well as popular detection techniques. Furthermore, this paper reviews some recent significant advances in point‐of‐care assays for rapid, accurate detection of cTnI as a smart integrated device for home monitoring. The accumulation of knowledge about these functions will lead to new insights into and concepts for the design of portable miniature sensors for cardiovascular patients at risk of AMI. It is anticipated that the interdisciplinary collaboration can bring more enlightenment to the progress of cardiac biomarkers sensor in the future.

Monitoring agricultural toxins such as mycotoxins is crucial for a healthy society. High concentrations of these toxins lead to the cause of several chronic diseases; therefore, developing analytical systems for detecting/monitoring agricultural toxins is essential. These toxins are found in crops such as vegetables, fruits, food, and beverage products. Currently, screening of these toxins is mostly performed with sophisticated instrumentation such as chromatography and spectroscopy techniques. However, these techniques are very expensive and require extensive maintenance, and their availability is limited to metro cities only. Alternatively, electrochemical biomimetic sensing methodologies have progressed hugely during the last decade due to their unique advantages like point-of-care sensing, miniaturized instrumentations, and mobile/personalized monitoring systems. Specifically, affinity-based sensing strategies including immunosensors, aptasensors, and molecular imprinted polymers offer tremendous sensitivity, selectivity, and stability to the sensing system. The current review discusses the principal mechanisms and the recent developments in affinity-based sensing methodologies for the detection and continuous monitoring of mycotoxins and pesticides. The core discussion has mainly focused on the fabrication protocols, advantages, and disadvantages of affinity-based sensing systems and different exploited electrochemical transduction techniques. [ABSTRACT FROM AUTHOR]

The need for performant analytical methodologies to assess mycotoxins is vital, given the negative health impact of these compounds. Biosensors are analytical devices that consist of a biological element for recognizing the analyte and a transducer, which translates the biorecognition event into a signal proportional to the analyte concentration. The biorecognition elements can be enzymes, antibodies, or DNA fragments. The modalities of detection can be optical, electrochemical, thermal, or mass-sensitive. These analytical tools represent viable alternatives to laborious, expensive traditional methods and are characterized by specificity given by the biorecognition element, sensitivity, fast response, portability, multi-modal detection, and the possibility of in situ application. The present paper focuses on a comprehensive view, enriched with a critical, comparative perspective on mycotoxin assay using biosensors. The use of different biorecognition elements and detection modes are discussed comparatively. Nanomaterials with optical and electrochemical features can be exploited in association with a variety of biorecognition elements. Analytical parameters are reviewed along with a broad range of applications. [ABSTRACT FROM AUTHOR]

The three decades of experience with piezoelectric devices applied in the field of bioanalytical chemistry are shared. After introduction to principles and suitable measuring approaches, active and passive methods based on oscillators and impedance analysis, respectively, the focus is directed towards biosensing approaches. Immunosensing examples are provided, followed by other affinity sensing approaches based on hybridization of nucleic acids, aptamers, monitoring of enzyme activities, and detection of pathogenic microbes. The combination of piezosensors with cell lines and testing of drugs is highlighted, including mechanically active cells. The combination of piezosensors with other measuring techniques providing original hybrid devices is briefly discussed. [ABSTRACT FROM AUTHOR]

To investigate the diagnostic and therapeutic potential of nanoparticle (NP)-based immunosensors in the field of oral cancer. PubMed, Embase, Scopus, Web of Science, and Google Scholar databases were explored for NP applications in oral cancer. Data extraction in terms and quality assessment of all the articles were done. Out of 147, 17 articles were included in this review. A majority of the studies showed improved sensitivity and specificity for saliva analysis using an enzyme-linked immunosorbent assay based on gold NPs, improving early identification. Additionally, novel therapeutic approaches, utilising NP-based immunosensors, demonstrated targeted drug delivery, coupled chemo-photothermal therapy, and gene silencing. Imaging methods have made it possible to distinguish between malignant and healthy states, such as surface-enhanced Raman scattering and optical coherence tomography. The reviews' findings highlight the transformational potential of NP-based immunosensors in addressing the difficulties associated with diagnosing and treating oral cancer. However, for an accurate interpretation and application of NP-based solutions in clinical practise, it is essential to be thoroughly aware of the intricacies involved, and the synthesised data in this review support the continued investigation and improvement of NP-based therapies in the ongoing effort to improve the management of oral cancer. [ABSTRACT FROM AUTHOR]

Abstract In diagnostic tools, rapid in vitro tests such as COVID‐19 antigen or pregnancy tests are gaining significance for identifying various pathologies or health conditions. This shift contributes to a change in the way diagnostic efforts are carried out, emphasizing decentralized approaches that offer valuable services within communities, yielding long‐term advantages for the healthcare system. Considering the substantial quantity of these tests manufactured and used annually, a straightforward manufacturing process is proposed for highly sensitive carbon electrodes designed for antibody‐type biomarker sensors. This process, utilizing pad printing – an additive, low‐temperature, and cost‐effective method, coupled with plasma activation – has proven the electrodes capability to measure interferon gamma protein, a tuberculosis biomarker. Using electrochemical impedance spectroscopy, the electrodes display high sensitivity and are capable of measuring concentrations from 10 to 1000 pg mL−1 in undiluted serum within an hour. The sensor, utilizing solely a monolayer of antibodies, achieves a performance equivalent to that of a commercial standard sandwich ELISA tested in this study.

Tetrodotoxin (TTX) is a highly potent and widely distributed ion-channel marine neurotoxin; it has no specific antidote and poses a great risk to human health. Therefore, detecting and quantifying TTX to effectively implement prevention strategies is important for food safety. The development of novel and highly sensitive, highly specific, rapid, and simple techniques for trace TTX detection has attracted widespread attention. This review summarizes the latest advances in the detection and quantitative analysis of TTX, covering detection methods based on biological and cellular sensors, immunoassays and immunosensors, aptamers, and liquid chromatography-mass spectrometry. It further discusses the advantages and applications of various detection technologies developed for TTX and focuses on the frontier areas and development directions of TTX detection, providing relevant information for further investigations.

Lung cancer has a high mortality rate largely due to late-stage diagnosis. Detecting protein and genetic biomarkers through electrochemical immunosensors enables non-invasive early diagnosis. This review discusses recent advances in electrochemical immunosensors for detecting clinically relevant lung cancer biomarkers. The use of nanomaterials like graphene, carbon nanotubes, metal nanoparticles, and conducting polymers in sensor fabrication improves electron transfer kinetics, enhances signal transduction, and allows higher antibody loading. Smart surface immobilization strategies optimize antibody orientation and binding capacity. Amplification approaches utilizing nanomaterials, enzymes, polymers, dendrimers, and DNA nanostructures are applied to enhance output signal per binding event. Various electroanalytical techniques including amperometry, potentiometry, impedance spectroscopy, and voltammetry are employed for quantitative monitoring. Recent immunosensors showcase low detection limits and wide linear ranges for measurement of major biomarkers like carcinoembryonic antigen, neuron specific enolase, and cytokeratin fragment 21-1. Emerging biomarkers such as microRNAs and circulating tumor cells have also been targeted. However, reproducibility, selectivity, multiplexing, and integration with point-of-care platforms need improvement for widespread clinical translation. Overall, electrochemical immunosensors hold immense potential for sensitive, affordable lung cancer diagnosis if ongoing efforts can address current limitations.

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.

This article highlights a label-free point-of-care detection of colistin (Polymyxin B) with modified immunosensor in chicken eggs. The manufacturing of screen-printed gold electrodes (Au-SPEs) is claimed to improve the sensor's sensitivity and point-of-care diagnostics, outperforming the outputs in terms of time and accuracy. The sensor attached a specific colistin antibody to a conventional Au-SPE that had been polyethyleneimine (PEI) modified by a carbodiimide-mediated amide coupling procedure. Using cyclic voltammetry (CV) and (K3Fe (CN)6)− as a redox probe during each stage of fabrication, this immunosensor captured the electrochemical changes in the sample laced with colistin. Characterization of Au-SPEs was done with AFM for surface morphology and topographic data and FTIR for the functional group confirmation. Limit of Detection (LOD) of 1.539 µg/kg of egg with high specificity toward antigen against other antibiotics was observed. Therefore, the proposed immunosensor based on Au-SPEs has potential applicability for early detection of colistin which could be a promising tool for its rapid detection. [ABSTRACT FROM AUTHOR]

Infectious diseases in farm animals triggered by pathogenic microorganisms affect the health and well-being of livestock and human populations. Pathogen detection is an important step for the successful diagnosis, treatment and control of infectious diseases in animals. Pathogens that persist in the poultry and livestock industries can be responsible for more than 70% of emerging infections. Thus, rapid diagnostic tools are extremely important. In recent years, nanotechnology has emerged as a great opportunity to tackle this challenge and to develop fast, accurate and economical diagnostics for the detection of pathogens. Various nanostructures, due to the presence of unique characteristics shown in nanomaterials, have already been applied in biodiagnostics to detect specific molecular targets, including pathogen detection. In this context, this review focuses on the application, role and challenges of nanosensors in detecting disease-causing pathogens in agriculture. Several nanostructures are investigated for their utility in providing innovative solutions for pathogen detection in farm animals. This comprehensive examination seeks to unravel the intricate nanosensors landscape, shedding some light on their role in advancing diagnostic capabilities within the agricultural domain. By elucidating the challenges inherent in their application, the review contributes to the ongoing discourse on harnessing nanotechnology for the detection and management of infectious diseases in livestock, ultimately paving the way for developments in veterinary diagnostics.

Plasmon‐induced hot carrier transfer is a promising approach for photoelectric applications, but its practical application is often hindered by its relatively narrow absorption bandwidth and low light harvesting at visible wavelengths. This work reports a broadband visible light plasmon‐absorber based on a dandelion‐like hierarchical metal‐semiconductor Au‐TiO2 core–shell nanostructure where each Au nanoparticle (AuNP) core is covered by an optically transparent mesh‐shell composed of TiO2 nanowires (TNWs) (denoted as AuTNW‐dCS). These AuTNW‐dCSs are assembled to form a 2D arrayed plasmonic monolayer by connecting adjacent AuNPs with cross‐linked TiO2 NWs, which can induce a remarkable broadband absorption in the visible spectrum of 500–700 nm. Driven by a wide light adsorption range, improved hot‐electron carriers, and excellent analyst's immobilization capability, the AuTNW‐dCS based photoelectric immunosensor owns excellent performance for alpha‐fetoprotein detection in human serum, with a practical linear range of 0.1–1000 ng mL−1, a low detection limit of 0.1 ng mL−1, and satisfying selectivity under visible light‐emitting diode light irradiation. This work enlightens the prospective research on the use of metal/semiconductor core–shell heterostructures as photoactive materials for sensing applications. Additionally, it gives an impetus for developing flexible nanofilms based on plasmonic metal/semiconductor nanohybrids, beneficial for building wearable point‐of‐need platform. [ABSTRACT FROM AUTHOR]

A major societal challenge is the development of the necessary tools for early diagnosis of diseases such as cancer and sepsis. Consequently, there is a concerted push to develop low-cost and non-invasive methods of analysis with high sensitivity and selectivity. A notable trend is the development of highly sensitive methods that are not only amenable for point-of-care (POC) testing, but also for wearable devices allowing continuous monitoring of biomarkers. In this context, a non-invasive test for the detection of a promising biomarker, the protein Interleukin-6 (IL-6), could represent a significant advance in the clinical management of cancer, in monitoring the chemotherapy response, or for prompt diagnosis of sepsis. This work reports a capacitive electrochemical impedance spectroscopy sensing platform tailored towards POC detection and treatment monitoring in human serum. The specific recognition of IL-6 was achieved employing gold surfaces modified with an anti-IL6 nanobody (anti-IL-6 VHH) or a specific IL-6 aptamer. In the first system, the anti-IL-6 VHH was covalently attached to the gold surface using a binary self-assembled-monolayer (SAM) of 6-mercapto-1-hexanol (MCH) and 11-mercaptoundecanoic acid. In the second system, the aptamer was chemisorbed onto the surface in a mixed SAM layer with MCH. The analytical performance for each label-free sensor was evaluated in buffer and 10% human serum samples and then compared. The results of this work were generated using a low-cost, thin film eight-channel gold sensor array produced on a flexible substrate providing useful information on the future design of POC and wearable impedance biomarker detection platforms. [ABSTRACT FROM AUTHOR]

Pesticides, chemical substances extensively employed in agriculture to optimize crop yields, pose potential risks to human and environmental health. Consequently, regulatory frameworks are in place to restrict pesticide residue concentrations in water intended for human consumption. These regulations are implemented to safeguard consumer safety and mitigate any adverse effects on the environment and public health. Although gas chromatography- and liquid chromatography-mass spectrometry (GC–MS and LC–MS) are highly efficient techniques for pesticide quantification, their use is not suitable for real-time monitoring due to the need for sophisticated laboratory pretreatment of samples prior to analysis. Since they would enable analyte detection with selectivity and sensitivity without sample pretreatment, biosensors appear as a promising alternative. These consist of a bioreceptor allowing for specific recognition of the target and of a detection platform, which translates the biological interaction into a measurable signal. As early detection systems remain urgently needed to promptly alert and act in case of pollution, we review here the biosensors described in the literature for pesticide detection to advance their development for use in the field. [ABSTRACT FROM AUTHOR]

An electrochemical immunosensor based on screen-printed graphite electrodes is developed for the determination of the antibiotic chloramphenicol in water and milk samples. It is shown that the immobilization of chloramphenicol-specific antibodies in the liquid-crystal layer of the membrane-like didodecyldimethylammonium bromide preserves the mobility and accessibility of active centers of antibodies, and the addition of gold nanoparticles improves the electron transfer from the electrode surface to the redox centers of horseradish peroxidase, which is used as a label. The limit of detection of chloramphenicol is 0.02 μg/L in water and 0.04 μg/L in milk. This method can be used to determine the residual amounts of chloramphenicol in animal products. [ABSTRACT FROM AUTHOR]

The need for performant analytical methodologies to assess mycotoxins is vital, given the negative health impact of these compounds. Biosensors are analytical devices that consist of a biological element for recognizing the analyte and a transducer, which translates the biorecognition event into a signal proportional to the analyte concentration. The biorecognition elements can be enzymes, antibodies, or DNA fragments. The modalities of detection can be optical, electrochemical, thermal, or mass-sensitive. These analytical tools represent viable alternatives to laborious, expensive traditional methods and are characterized by specificity given by the biorecognition element, sensitivity, fast response, portability, multi-modal detection, and the possibility of in situ application. The present paper focuses on a comprehensive view, enriched with a critical, comparative perspective on mycotoxin assay using biosensors. The use of different biorecognition elements and detection modes are discussed comparatively. Nanomaterials with optical and electrochemical features can be exploited in association with a variety of biorecognition elements. Analytical parameters are reviewed along with a broad range of applications.

Monitoring agricultural toxins such as mycotoxins is crucial for a healthy society. High concentrations of these toxins lead to the cause of several chronic diseases; therefore, developing analytical systems for detecting/monitoring agricultural toxins is essential. These toxins are found in crops such as vegetables, fruits, food, and beverage products. Currently, screening of these toxins is mostly performed with sophisticated instrumentation such as chromatography and spectroscopy techniques. However, these techniques are very expensive and require extensive maintenance, and their availability is limited to metro cities only. Alternatively, electrochemical biomimetic sensing methodologies have progressed hugely during the last decade due to their unique advantages like point-of-care sensing, miniaturized instrumentations, and mobile/personalized monitoring systems. Specifically, affinity-based sensing strategies including immunosensors, aptasensors, and molecular imprinted polymers offer tremendous sensitivity, selectivity, and stability to the sensing system. The current review discusses the principal mechanisms and the recent developments in affinity-based sensing methodologies for the detection and continuous monitoring of mycotoxins and pesticides. The core discussion has mainly focused on the fabrication protocols, advantages, and disadvantages of affinity-based sensing systems and different exploited electrochemical transduction techniques.

Abstract Plasmon‐induced hot carrier transfer is a promising approach for photoelectric applications, but its practical application is often hindered by its relatively narrow absorption bandwidth and low light harvesting at visible wavelengths. This work reports a broadband visible light plasmon‐absorber based on a dandelion‐like hierarchical metal‐semiconductor Au‐TiO2 core–shell nanostructure where each Au nanoparticle (AuNP) core is covered by an optically transparent mesh‐shell composed of TiO2 nanowires (TNWs) (denoted as AuTNW‐dCS). These AuTNW‐dCSs are assembled to form a 2D arrayed plasmonic monolayer by connecting adjacent AuNPs with cross‐linked TiO2 NWs, which can induce a remarkable broadband absorption in the visible spectrum of 500–700 nm. Driven by a wide light adsorption range, improved hot‐electron carriers, and excellent analyst's immobilization capability, the AuTNW‐dCS based photoelectric immunosensor owns excellent performance for alpha‐fetoprotein detection in human serum, with a practical linear range of 0.1–1000 ng mL−1, a low detection limit of 0.1 ng mL−1, and satisfying selectivity under visible light‐emitting diode light irradiation. This work enlightens the prospective research on the use of metal/semiconductor core–shell heterostructures as photoactive materials for sensing applications. Additionally, it gives an impetus for developing flexible nanofilms based on plasmonic metal/semiconductor nanohybrids, beneficial for building wearable point‐of‐need platform.

Cholera, a persistent global public health concern, continues to cause outbreaks in approximately 30 countries and territories this year. The imperative to safeguard water sources and food from Vibrio cholerae, the causative pathogen, remains urgent. The bacterium is mainly disseminated via ingestion of contaminated water or food. Despite the plate method's gold standard status for detection, its time-consuming nature, taking several days to provide results, remains a challenge. The emergence of novel virulence serotypes raises public health concerns, potentially compromising existing detection methods. Hence, exploiting Vibrio cholerae toxin testing holds promise due to its inherent stability. Immunobiosensors, leveraging antibody specificity and sensitivity, present formidable tools for detecting diverse small molecules, encompassing drugs, hormones, toxins, and environmental pollutants. This review explores cholera toxin detection, highlighting phage display-based nano immunosensors' potential. Engineered bacteriophages exhibit exceptional cholera toxin affinity, through specific antibody fragments or mimotopes, enabling precise quantification. This innovative approach promises to reshape cholera toxin detection, offering an alternative to animal-derived methods. Harnessing engineered bacteriophages aligns with ethical detection and emphasizes sensitivity and accuracy, a pivotal stride in the evolution of detection strategies. This review primarily introduces recent advancements in phage display-based nano immunosensors for cholera toxin, encompassing technical aspects, current challenges, and future prospects. [ABSTRACT FROM AUTHOR]

Herein, we have highlighted the latest developments on biosensors for cancer cell detection. Electrochemical (EC) biosensors offer several advantages such as high sensitivity, selectivity, rapid analysis, portability, low‐cost, etc. Generally, biosensors could be classified into other basic categories such as immunosensors, aptasensors, cytosensors, electrochemiluminescence (ECL), and photo‐electrochemical (PEC) sensors. The significance of the EC biosensors is that they could detect several biomolecules in human body including cholesterol, glucose, lactate, uric acid, DNA, blood ketones, hemoglobin, and others. Recently, various EC biosensors have been developed by using electrocatalytic materials such as silver sulfide (Ag2S), black phosphene (BPene), hexagonal carbon nitrogen tube (HCNT), carbon dots (CDs)/cobalt oxy‐hydroxide (CoOOH), cuprous oxide (Cu2O), polymer dots (PDs), manganese oxide (MnO2), graphene derivatives, and gold nanoparticles (Au‐NPs). In some cases, these newly developed biosensors could be able to detect cancer cells with a limit of detection (LOD) of 1 cell/mL. In addition, many remaining challenges have to be addressed and validated by testing more real samples and confirm that these EC biosensors are more accurate and reliable to measure cancer cells in the blood and salivary samples. [ABSTRACT FROM AUTHOR]

Antibiotics have emerged as ground-breaking medications for the treatment of infectious diseases, but due to the excessive use of antibiotics, some drugs have developed resistance to microorganisms. Because of their structural complexity, most antibiotics are excreted unchanged, polluting the water, soil, and natural resources. Additionally, food items are being polluted through the widespread use of antibiotics in animal feed. The normal concentrations of antibiotics in environmental samples typically vary from ng to g/L. Antibiotic residues in excess of these values can pose major risks the development of illnesses and infections/diseases. According to estimates, 300 million people will die prematurely in the next three decades (by 2050), and the WHO has proclaimed "antibiotic resistance" to be a severe economic and sociological hazard to public health. Several antibiotics have been recognised as possible environmental pollutants (EMA) and their detection in various matrices such as food, milk, and environmental samples is being investigated. Currently, chromatographic techniques coupled with different detectors (e.g., HPLC, LC-MS) are typically used for antibiotic analysis. Other screening methods include optical methods, ELISA, electrophoresis, biosensors, etc. To minimise the problems associated with antibiotics (i.e., the development of AMR) and the currently available analytical methods, electrochemical platforms have been investigated, and can provide a cost-effective, rapid and portable alternative. Despite the significant progress in this field, further developments are necessary to advance electrochemical sensors, e.g., through the use of multi-functional nanomaterials and advanced (bio)materials to ensure efficient detection, sensitivity, portability, and reliability. This review summarises the use of electrochemical biosensors for the detection of antibiotics in milk/milk products and presents a brief introduction to antibiotics and AMR followed by developments in the field of electrochemical biosensors based on (i) immunosensor, (ii) aptamer (iii) MIP, (iv) enzyme, (v) whole-cell and (vi) direct electrochemical approaches. The role of nanomaterials and sensor fabrication is discussed wherever necessary. Finally, the review discusses the challenges encountered and future perspectives. This review can serve as an insightful source of information, enhancing the awareness of the role of electrochemical biosensors in providing information for the preservation of the health of the public, of animals, and of our environment, globally. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are often used as carriers in the preparation of electrochemiluminescent (ECL) materials, and ECL materials stabilized in the aqueous phase can be prepared by encapsulating chromophores inside MOFs by an in situ growth method. In this study, nanocomposites MIL-88B(Fe)-NH2@Ru(py)32+ with excellent ECL response were prepared by encapsulating Tris(2,2′-bipyridine)ruthenium dichloride (Ru(py)32+) inside MIL-88B(Fe)-NH2 using the one-step hydrothermal method. MIL-88B(Fe)-NH2 possesses abundant amino groups, which can accelerate the catalytic activation process of K2S2O8, and its abundant pores are also conducive to the enhancement of the transmission rate of co-reactant agents, ions, and electrons, which effectively improves the ECL efficiency. In order to obtain more excellent ECL signals, we prepared aminated biochar (NH2-biochar) using Pu-erh tea dregs as precursor and loaded gold nanoparticles (Au NPs) on its surface as substrate material for modified electrodes. Both NH2-biochar and Au NPs can also be used as a co-reactant promoter to catalyze the activation process of co-reactant K2S2O8. Therefore, a sandwich-type ECL immunosensor was prepared based on a dual signal-enhanced strategy for the highly sensitive and selective detection of aflatoxin B1 (AFB1). Under the optimal experimental conditions, the sensitive detection of AFB1 was achieved in the range of 1 pg·mL−1~100 ng·mL−1 with a detection limit of 209 fg·mL−1. The proposed dual signal-enhanced ECL immunosensor can provide a simple, convenient, and efficient method for the sensitive detection of AFB1 in food and agricultural products. [ABSTRACT FROM AUTHOR]

Immunosensors are a special class of biosensors that employ specific antibodies for biorecognition of the target analyte. Immunosensors that target disease biomarkers may be exploited as tools for disease diagnosis and/or follow-up, offering several advantages over conventional analytical techniques, such as rapid and easy analysis of patients' samples at the point-of-care. Autoimmune diseases have been increasingly prevalent worldwide in recent years, while the COVID-19 pandemic has also been associated with autoimmunity. Consequently, demand for tools enabling the early and reliable diagnosis of autoimmune diseases is expected to increase in the near future. To this end, interest in immunosensors targeting autoimmune disease biomarkers, mainly, various autoantibodies and specific pro-inflammatory proteins (e.g., specific cytokines), has been rekindled. This review article presents most of the immunosensors proposed to date as potential tools for the diagnosis of various autoimmune diseases, such as type 1 diabetes, rheumatoid arthritis, and multiple sclerosis. The signal transduction and the immunoassay principles of each immunosensor have been suitably classified and are briefly presented along with certain sensor elements, e.g., special nano-sized materials used in the construction of the immunosensing surface. The main concluding remarks are presented and future perspectives of the field are also briefly discussed. [ABSTRACT FROM AUTHOR]

The traditional lateral flow immunoassay (LFIA) detection method suffers from issues such as unstable detection results and low quantitative accuracy. In this study, we propose a novel multi-test line lateral flow immunoassay quantitative detection method using smartphone-based SAA immunoassay strips. Following the utilization of image processing techniques to extract and analyze the pigments on the immunoassay strips, quantitative analysis of the detection results was conducted. Experimental setups with controlled lighting conditions in a dark box were designed to capture samples using smartphones with different specifications for analysis. The algorithm's sensitivity and robustness were validated by introducing noise to the samples, and the detection performance on immunoassay strips using different algorithms was determined. The experimental results demonstrate that the proposed lateral flow immunoassay quantitative detection method based on image processing techniques achieves an accuracy rate of 94.23% on 260 samples, which is comparable to the traditional methods but with higher stability and lower algorithm complexity. [ABSTRACT FROM AUTHOR]

Due to their capacity to immobilize more bioreceptor parts at reduced volumes, nanomaterials have emerged as potential tools for increasing the sensitivity to specific molecules. Furthermore, carbon nanotubes, gold nanoparticles, polymer nanoparticles, semiconductor quantum dots, nanodiamonds, and graphene are among the nanomaterials that are under investigation. Due to the fast development of this field of research, this review summarizes the classification of biosensors using the main receptors and design of biosensors. Numerous studies have concentrated on the manipulation of persistent luminescence nanoparticles (PLNPs) in biosensing, cell tracking, bioimaging, and cancer therapy due to the effective removal of autofluorescence interference from tissues and the ultra‐long near‐infrared afterglow emission. As luminescence has a unique optical property, it can be detected without constant external illumination, preventing autofluorescence and light dispersion through tissues. These successes have sparked an increasing interest in creating novel PLNP types with the desired superior properties and multiple applications. In this review, we emphasize the most recent developments in biosensing, imaging, and image‐guided therapy whilst summarizing the research on synthesis methods, bioapplications, biomembrane modification, and the biosafety of PLNPs. Finally, the remaining issues and difficulties are examined together with prospective future developments in the biomedical application field. [ABSTRACT FROM AUTHOR]

Hyaluronic acid (HA) is the main non-sulfated glycosaminoglycan of the extracellular matrix that is synthesized by fibroblasts and other specialized connective tissue cells. The accumulation of HA on different tissues is a characteristic of disorders that are associated with progressive tissue fibrosis. HA is also known to play a critical role in tumorigenesis and tumor metastasis. It is overproduced by many types of tumors and promotes tumor progression and multidrug resistance. There is a great necessity for the development of an easy and cost-effective detection method for the monitoring of HA for both the diagnosis and efficient treatment of related disorders. In the present study, an innovative immune device was designed for the rapid and sensitive recognition of HA in human plasma samples. For this purpose, an efficient alloy (Pt@Au) was fabricated on the surface of the gold electrode. Thus, a novel substrate was used for the preparation of an efficient transducer, which is necessary for the immobilization of biotinylated antibodies. CHA was applied for the electrochemical deposition of Pt@Au nano-alloy on Au electrodes. Additionally, the morphological study of the used nanocomposite was assessed using FESEM at a working voltage of 3 kV, and the chemical structures of the electrode were analyzed using the EDS apparatus. For the first time, a biocompatible alloy-based substrate was prepared for the study of antigen–antibody identification. The developed immunosensor has a linear response within the range of 0.156–160 ng.mL−1 with a limit of detection of 0.039 ng.mL−1 in human plasma samples. This research study offers a novel promising technique for HA analyses and is anticipated to be used in the early diagnosis of some disorders related to abnormal levels of HA in human bio-fluids. Thus, a constructed (pt@Au) nano-alloy provides a useful interface for the dense loading of AB. This excellent design loads high sensations of the biosensor for the selective detection of HA in real samples (human bio-fluids). [ABSTRACT FROM AUTHOR]

Lasers are emerging as novel photonic tags for single‐cell labeling, anticounterfeiting, and encryption technology due to their narrow linewidth, high spectral multiplexing capacity, and superior stimuli‐responsiveness. These laser‐encoded photonic tags mostly distinguish the heterogeneity but do not yet provide both tagging and sensing of biosamples, which is highly desirable for disease screening. Here, a photonic bandgap (PBG) fiber microlaser that works as a 2D tag and an immunosensor is developed. The tubular PBG structure allows strong light–matter interaction and supports dual‐band lasing in the same optical fiber, enabling massive biosample tagging and sensitive biodetection. By encoding the random resonant peaks in the short‐wave band and multiplexing in the spatial domain, a 2D laser tag is generated with a large encoding capacity (>28500). Immunosensing of microalbumin is realized by using the periodic resonant peaks in the long‐wave band, and a limit of detection of 0.06 ng µL−1 is achieved. This work is inspiring for the development of high‐performance, multifunctional integrated devices for disease screening. [ABSTRACT FROM AUTHOR]

Electrochemical biosensors are known as analytical tools, guaranteeing rapid and on-site results in medical diagnostics, food safety, environmental protection, and life sciences research. Current research focuses on developing sensors for specific targets and addresses challenges to be solved before their commercialization. These challenges typically include the lowering of the limit of detection, the widening of the linear concentration range, the analysis of real samples in a real environment and the comparison with a standard validation method. Nowadays, functional nanomaterials are designed and applied in electrochemical biosensing to support all these challenges. This review will address the integration of functional nanomaterials in the development of electrochemical biosensors for the rapid diagnosis of viral infections, such as COVID-19, middle east respiratory syndrome (MERS), influenza, hepatitis, human immunodeficiency virus (HIV), and dengue, among others. The role and relevance of the nanomaterial, the type of biosensor, and the electrochemical technique adopted will be discussed. Finally, the critical issues in applying laboratory research to the analysis of real samples, future perspectives, and commercialization aspects of electrochemical biosensors for virus detection will be analyzed. [ABSTRACT FROM AUTHOR]

Electrochemical immunosensors comprise the merging of two different disciplines: molecular biology and electrochemistry. This review explains in depth the main parts of electrochemical immunosensors and how the enzyme‐linked immunosorbent assay (ELISA) has been integrated into sophisticated "lab‐on‐a‐chip" and "point‐of‐care" devices. It also reviews how nanotechnology has been a powerful tool for achieving lower detection limits, more signal amplification, and constructing label‐free devices. It finally explores the new perspectives on electrochemical immunosensors to integrate them in novel paper microfluidic devices called EμPADs. Colleagues introducing themselves to the topic for the first time will find in this review a comprehensive revision of how the basics of the technology have given rise to the emerging topic of EμPADs. [ABSTRACT FROM AUTHOR]

Food security is significantly affected by the mass production of agricultural produce and goods, the growing number of imported foods, and new eating and consumption habits. These changed circumstances bring food safety issues arising from food spoilage to the fore, making food safety control essential. Simple and fast screening methods have been developed to detect pathogens and biomarkers indicating the freshness of food for safety. In addition to the traditional, sequential, chemical analytical and microbiological methods, fast, highly sensitive, automated methods suitable for serial tests have appeared. At the same time, biosensor research is also developing dynamically worldwide, both in terms of the analytes to be determined and the technical toolkit. Consequently, the rapid development of biosensors, including electrochemical-based biosensors, has led to significant advantages in the quantitative detection and screening of food contaminants. These techniques show great specificity for the biomarkers tested and provide adequate analytical accuracy even in complex food matrices. In our review article, we summarize, in separate chapters, the electrochemical biosensors developed for the most important food groups and the food safety issues they can ensure, with particular respect to meat and fish products, milk and dairy products, as well as alcoholic and non-alcoholic beverages. [ABSTRACT FROM AUTHOR]

Electrochemical immunosensors are often described as innovative strategies to tackle urgent epidemiological needs, such as the detection of SARS-CoV-2 main biomarker, the spike glycoprotein. Nevertheless, there is a great variety of receptors, especially recombinant antibodies, that can be used to develop these biosensing platforms, and very few reports compare their suitability in analytical device design and their sensing performances. Therefore, this short report targeted a brief and straightforward investigation of the performance of different impedimetric biorecognition surfaces (BioS) for SARS-CoV-2, which were crafted from three commonly reported recombinant antibodies and molecularly-imprinted polymer (MIP) nanoparticles (nanoMIP). The selected NanoMIP were chosen due to their reported selectivity to the receptor binding domain (RBD) of SARS-CoV-2 spike glycoprotein. Results showed that the surface modification protocol based on MUDA and crosslinking with EDC/NHS was successful for the anchoring of each tested receptor, as the semicircle diameter of the Nyquist plots of EIS increased upon each modification, which suggests the increase of Rct due to the binding of dielectric materials on the conductive surface. Furthermore, the type of monoclonal antibody used to craft the BioS and the artificial receptors led to very distinct responses, being the RBD5305 and the NanoMIP-based BioS the ones that showcased the highest increment of signal in the conditions herein reported, which suggests their adequacy in the development of impedimetric immunosensors for SARS-CoV-2 spike glycoprotein.

PCBs (polychlorinated biphenyls) are a very large group of organic compounds that have between two and ten chlorine atoms attached to the biphenyl. These compounds have an acute impact as environmental pollutants, causing cancer and other adverse health effects in humans. It is therefore imperative to develop techniques for the cost-effective detection of PCBs at very low concentrations in ecosystems. In this paper, a novel label-free, indirect, competitive electrochemical immunosensor was first developed with a PCB-BSA conjugate. It is shown herein to compete with free PCBs for binding to the anti-PCB polyclonal primary antibody (IgY). Then, we used a secondary antibody to enhance the sensitivity of the sensor for the detection of PCB in a sample. It has been successfully immobilized on an 11-mercaptoundecanoic acid (11-MUA)-modified gold electrode via a carbodiimide-coupling reaction using cross-linking 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) on the electrode surface. The immunosensor was investigated by cyclic voltammetry and differential pulse voltammetry in a standard solution of [Fe(CN)6]3−/4−. A linear range of 0.011–220 ng/mL−1 and a limit of detection (LOD) of 0.11 ng/mL−1 for PCBs detection were achieved by the developed immunosensor, showing advantages over conventional assays. The novel label-free electrochemical immunosensor discussed in this paper is a solution for simple, rapid, cost-effective sample screening in a portable, disposable format. The proposed immunosensor has good sensitivity, and it can prove to be an adequate real-time monitoring solution for PCBs in soil samples or other samples.