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Antimicrobial resistance (AMR) poses a significant threat to global health, powered by pathogens that become increasingly proficient at withstanding antibiotic treatments. This review introduces the factors contributing to antimicrobial resistance (AMR), highlighting the presence of antibiotics in different environmental and biological matrices as a significant contributor to the resistance. It emphasizes the urgent need for robust and effective detection methods to identify these substances and mitigate their impact on AMR. Traditional techniques, such as liquid chromatography-mass spectrometry (LC-MS) and immunoassays, are discussed alongside their limitations. The review underscores the emerging role of biosensors as promising alternatives for antibiotic detection, with a particular focus on electrochemical biosensors. Therefore, the manuscript extensively explores the principles and various types of electrochemical biosensors, elucidating their advantages, including high sensitivity, rapid response, and potential for point-of-care applications. Moreover, the manuscript investigates recent advances in materials used to fabricate electrochemical platforms for antibiotic detection, such as aptamers and molecularly imprinted polymers, highlighting their role in enhancing sensor performance and selectivity. This review culminates with an evaluation and summary of commercially available and spin-off sensors for antibiotic detection, emphasizing their versatility and portability. By explaining the landscape, role, and future outlook of electrochemical biosensors in antibiotic detection, this review provides insights into the ongoing efforts to combat the escalating threat of AMR effectively.

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BACKGROUND: Optical fiber sensors have been used to detect glucose owing to advantages such as low cost, small size, and ease of operation etc. phenylboronic acid is one of the commonly used receptors for glucose detection, however phenylboronic acid based regenerative optical fiber sensors are commonly cumulative regeneration, renewable regeneration sensor has been missing from the literature. RESULTS: In this work, instead of using phenylboronic acid, we synthesized succinylaminobenzenoboronic acid molecule (BPOA) by introducing a short chain containing carboxyl group at the other end of phenylboronic acid then covalently bonded BPOA on the surface of excessively tilted fiber grating (Ex-TFG). This provides a very stable platform for renewable regeneration and the regenerative buffer was also optimized. The proposed renewable regeneration method exhibited higher linearity and sensitivity (R2 = 0.9992, 8 pm/mM) in relative to the conventional cumulative regeneration method (R2 = 0.9718, 4.9 pm/mM). The binding affinity between BPOA and glucose was found to be almost constant over 140 bind/release cycles with a variation of less than 0.3 % relative standard deviation. SIGNIFICANCE: The regenerative and label-free sensing capacity of the proposed device provides a theoretical foundation for label-free saccharide detection and the development of wearable glucose monitoring devices based on fiber optic sensors.

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Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium that remains a prevalent clinical and environmental challenge. Quorum-sensing (QS) molecules are effective biomarkers in pinpointing the presence of P. aeruginosa. This study aimed to develop a convenient-to-use, whole-cell biosensor using P. aeruginosa reporters individually encapsulated within alginate-poly-L-lysine (alginate-PLL) microbeads to specifically detect the presence of bacterial autoinducers. The PLL-reinforced microbeads were prepared using a two-step method involving ionic cross-linking and subsequent coating with thin layers of PLL. The alginate-PLL beads showed good stability in the presence of a known cation scavenger (sodium citrate), which typically limits the widespread applications of calcium alginate. In media containing synthetic autoinducers-such as N-(3-oxo dodecanoyl) homoserine lactone (3-oxo-C12-HSL) and N-butanoyl-L-homoserine lactone (C4-HSL), or the cell-free supernatants of planktonic or the flow-cell biofilm effluent of wild P. aeruginosa (PAO1)-the encapsulated bacteria enabled a dose-dependent detection of the presence of these QS molecules. The prepared bioreporter beads remained stable during prolonged storage at 4 and -80 °C and were ready for on-the-spot sensing without the need for recovery. The proof-of-concept, optical fiber-based, and whole-cell biosensor developed here demonstrates the practicality of the encapsulated bioreporter for bacterial detection based on specific QS molecules.

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Biosensors are used for the specific and sensitive detection of biomolecules. In conventional approaches, the suspected target molecules are bound to selected capture molecules and successful binding is indicated by additional labelling to enable optical readout. This labelling requires additional processing steps tailored to the application. While numerous label-free interaction assays exist, they often compromise on detection characteristics. In this context, we introduce a novel diffractometric biosensor, comprising a diffractive biosensor chip and an associated optical reader assembly. This innovative system can capture an entire assay, detecting various types of molecules in a label-free manner and present the results within in a single, comprehensive image. The applicability of the biosensor is assessed for the detection of viral DNA as well as proteins directly in human plasma, investigating different antigens. In our experiments, we achieve a detection limit of 4.2 pg/mm², which is comparable to other label-free optical biosensors. The simplicity and robustness of the method make it a compelling option for advancing biosensing technologies. This work contributes to the development of an imaging diffractometric biosensor with the potential for multiple applications in molecular interaction analysis.

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Aquaculture is expected to play a vital role in solving the challenge of sustainably providing the growing world population with healthy and nutritious food. Pathogen outbreaks are a major risk for the sector, so early detection and a timely response are crucial. This can be enabled by monitoring the pathogen levels in aquaculture facilities. This paper describes a photonic biosensing platform based on silicon nitride waveguide technology with integrated active components, which could be used for such applications. Compared to the state of the art, the current system presents improvements in terms of miniaturization of the Photonic Integrated Circuit (PIC) and the development of wafer-level processes for hybrid integration of active components and for material-selective chemical and biological surface modification. Furthermore, scalable processes for integrating the PIC in a microfluidic cartridge were developed, as well as a prototype desktop readout instrument. Three bacterial aquaculture pathogens (Aeromonas salmonicida, Vagococcus salmoninarum, and Yersinia ruckeri) were selected for assay development. DNA biomarkers were identified, corresponding primer-probe sets designed, and qPCR assays developed. The biomarker for Aeromonas was also detected using the hybrid PIC platform. This is the first successful demonstration of biosensing on the hybrid PIC platform.

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In the relentless pursuit of innovative diagnostic tools for cancer, this review illuminates the cutting-edge realm of extracellular vesicles (EVs) and their biomolecular cargo detection through advanced optical biosensing techniques with a primary emphasis on their significance in cancer diagnosis. From the sophisticated domain of nanomaterials to the precision of surface plasmon resonance, we herein examine the diverse universe of optical biosensors, emphasizing their specified applications in cancer diagnosis. Exploring and understanding the details of EVs, we present innovative applications of enhancing and blending signals, going beyond the limits to sharpen our ability to sense and distinguish with greater sensitivity and specificity. Our special focus on cancer diagnosis underscores the transformative potential of optical biosensors in early detection and personalized medicine. This review aims to help guide researchers, clinicians, and enthusiasts into the captivating domain where light meets cellular secrets, creating innovative opportunities in cancer diagnostics.

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Single-walled carbon nanotubes (SWNT) have a strong and stable near-infrared (nIR) fluorescence that can be used to selectively detect target analytes, even at the single molecule level, through changes in either their fluorescence intensity or emission peak wavelength. SWNTs have been employed as NIR optical sensors for detecting a variety of analytes. However, high costs, long fabrication times, and poor distributions limit the current methods for immobilizing SWNT sensors on solid substrates. Recently, our group reported a protocol for SWNT immobilization with high fluorescence yield, longevity, fluorescence distribution, and sensor response, unfortunately this process takes 5 days to complete. Herein we report an improved method to immobilize SWNT sensors that only takes 2 days and results in higher fluorescence intensity while maintaining a high level of SWNT distribution. We performed surface morphology and chemical composition tests on the original and new synthesis methods and compared the sensor response rates. The development of this new method of attaching SWNT sensors to a platform allows for creation of a sensing system in just 2 days without sacrificing the advantageous characteristics of the original, 5-day platforms.

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In this study, we report the successful development of a novel high-sensitivity intensity-based Surface Plasmon Resonance imaging (SPRi) biosensor and its application for detecting molecular interactions. By optimizing the excitation wavelength and employing a wavelength division multiplexing (WDM) algorithm, the system can determine the optimal excitation wavelength based on the initial refractive index of the sample without adjusting the incidence angle. The experimental results demonstrate that the refractive index resolution of the system reaches 1.77×10-6 RIU. Moreover, it can obtain the optimal excitation wavelength for samples with an initial refractive index in the range of 1.333 to 1.370 RIU and accurately monitor variations within the range of 0.0037 RIU without adjusting the incidence angle. Additionally, our new SPRi technique realized real-time detection of high-throughput biomolecular binding processes, enabling analysis of kinetic parameters. This research is expected to advance the development of more accurate SPRi technologies for molecular interaction analysis.

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The advancement of nanoscience and material design in recent times has facilitated the creation of point-of-care devices for cancer diagnosis and biomolecule sensing. Exosomes (EXOs) facilitate the transfer of bioactive molecules between cancer cells and diverse cells in the local and distant microenvironments, thereby contributing to cancer progression and metastasis. Specifically, EXOs derived from cancer are likely to function as biomarkers for early cancer detection due to the genetic or signaling alterations they transport as payload within the cancer cells of origin. It has been verified that EXOs circulate steadily in bodily secretions and contain a variety of information that indicates the progression of the tumor. However, acquiring molecular information and interactions regarding EXOs has presented significant technical challenges due to their nanoscale nature and high heterogeneity. Colorimetry, surface plasmon resonance (SPR), fluorescence, and Raman scattering are examples of optical techniques utilized to quantify cancer exosomal biomarkers, including lipids, proteins, RNA, and DNA. Many optically active nanoparticles (NPs), predominantly carbon-based, inorganic, organic, and composite-based nanomaterials, have been employed in biosensing technology. The exceptional physical properties exhibited by nanomaterials, including carbon NPs, noble metal NPs, and magnetic NPs, have facilitated significant progress in the development of optical nanobiosensors intended for the detection of EXOs originating from tumors. Following a summary of the biogenesis, biological functions, and biomarker value of known EXOs, this article provides an update on the detection methodologies currently under investigation. In conclusion, we propose some potential enhancements to optical biosensors utilized in detecting EXO, utilizing various NP materials such as silicon NPs, graphene oxide (GO), metal NPs, and quantum dots (QDs).

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Optical biosensors have employed at least three distinct system architectures over the last 40 years, moving from "sample in-answer out" systems to completely embedding the optical biosensor into the sample to embedding the recognition module in the sample and optically interrogating the recognition module from outside of the sample. This trends article provides an overview of the evolution of these three system architectures and discusses how each architecture has been applied to solve the measurement challenges of a wide variety of applications. A fourth biosensor system architecture, that of an "autonomous" biosensor which "takes the user out of the loop" while both detecting target analytes and responding to that measurement, is currently under development for applications initially including environmental cleanup and "smart therapeutics." As is the case in many other areas of technology, it will be profoundly interesting to observe the further development and application of elegant, simpler (optical) biosensor systems to address tomorrow's measurement needs.

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The rapid developments in the field of zeolitic imidazolate frameworks (ZIFs) in recent years have created unparalleled opportunities for the development of unique bioactive ZIFs for a range of biosensor applications. Integrating bioactive molecules such as DNA, aptamers, and antibodies into ZIFs to create bioactive ZIF composites has attracted great interest. Bioactive ZIF composites have been developed that combine the multiple functions of bioactive molecules with the superior chemical and physical properties of ZIFs. This review thoroughly summarizes the ZIFs as well as the novel strategies for incorporating bioactive molecules into ZIFs. They are used in many different applications, especially in biosensors. Finally, biosensor applications of bioactive ZIFs were investigated in optical (fluorescence and colorimetric) and electrochemical (amperometric, conductometric, and impedance) fields. The surface of ZIFs makes it easier to immobilize bioactive molecules like DNA, enzymes, or antibodies, which in turn enables the construction of cutting-edge, futuristic biosensors.

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Small molecule natural compounds are gaining popularity in biomedicine due to their easy access to wide structural diversity and their proven health benefits in several case studies. Affinity measurements of small molecules below 100 Da molecular weight in a label-free and automatized manner using small amounts of samples have now become a possibility and reviewed in the present work. We also highlight novel label-free setups with excellent time resolution, which is important for kinetic measurements of biomolecules and living cells. We summarize how molecular-scale affinity data can be obtained from the in-depth analysis of cellular kinetic signals. Unlike traditional measurements, label-free biosensors have made such measurements possible, even without the isolation of specific cellular receptors of interest. Throughout this review, we consider epigallocatechin gallate (EGCG) as an exemplary compound. EGCG, a catechin found in green tea, is a well-established anti-inflammatory and anti-cancer agent. It has undergone extensive examination in numerous studies, which typically rely on fluorescent-based methods to explore its effects on both healthy and tumor cells. The summarized research topics range from molecular interactions with proteins and biological films to the kinetics of cellular adhesion and movement on novel biomimetic interfaces in the presence of EGCG. While the direct impact of small molecules on living cells and biomolecules is relatively well investigated in the literature using traditional biological measurements, this review also highlights the indirect influence of these molecules on the cells by modifying their nano-environment. Moreover, we underscore the significance of novel high-throughput label-free techniques in small molecular measurements, facilitating the investigation of both molecular-scale interactions and cellular processes in one single experiment. This advancement opens the door to exploring more complex multicomponent models that were previously beyond the reach of traditional assays.

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The high toxicity and occurrence of ochratoxin A (OTA) in grains and foods has been a growing concern due to the impacts on health and the economy in many countries. In this sense, simplified devices with high sensitivity and specificity for local monitoring are enthusiastically pursued. In this work, we report for the first time the detection of ochratoxin A in coffee samples using a spoon-shaped waveguide immunosensor. The biosensor was built with the surface of the spoon-shaped waveguide covered by a 60 nm layer of gold to enable the SPR phenomenon. The measurements indicated a linear relationship between the change in the SPR phenomenon values and the OTA concentration in the range from 0.2 ppt to 5 ppt. When analyzed in coffee samples, the biosensor was highly selective and did not suffer matrix interference. The developed biosensor represents a promising analytical device for coffee quality analyses, as it is portable, simple, and suitable for onsite detection of target analytes.

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Viral pandemic diseases have disruptive global consequences leading to millions of deaths and a severe impact on the global economy. Inadequate preventative protocols have led to an overwhelming demand for intensive care leading to uncontrollable burdens and even breakdown of healthcare sectors across many countries. The rapid detection of viral disease helps in the understanding of the relevant intricacies, helping to tackle infection with improved guidelines. Portable biosensor devices offer promising solutions by facilitating on-site detection of viral pathogens. This review summarizes the latest innovative strategies reported using electroanalytical methods for the screening of viral antigens. The structural components of viruses and their categories are presented followed by the various recognition elements and transduction techniques involved in biosensors. Core sections focus on biosensors reported for viral genomic detection(DNA and RNA) and antigenic capsid protein. Strategies for addressing the challenges of electroanalytical biosensing of viral components are also presented. The advantages, and disadvantages of biorecognition elements and nanozymes for the detection of viral disease are highlighted. Such technical insights will help researchers working in chemistry, and biochemistry as well as clinicians working in medical diagnostics.

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Technological progress has led to the development of analytical tools that promise a huge socio-economic impact on our daily lives and an improved quality of life for all. The use of plant extract synthesized nanoparticles in the development and fabrication of optical or electrochemical (bio)sensors presents major advantages. Besides their low-cost fabrication and scalability, these nanoparticles may have a dual role, serving as a transducer component and as a recognition element, the latter requiring their functionalization with specific components. Different approaches, such as surface modification techniques to facilitate precise biomolecule attachment, thereby augmenting recognition capabilities, or fine tuning functional groups on nanoparticle surfaces are preferred for ensuring stable biomolecule conjugation while preserving bioactivity. Size optimization, maximizing surface area, and tailored nanoparticle shapes increase the potential for robust interactions and enhance the transduction. This article specifically aims to illustrate the adaptability and effectiveness of these biosensing platforms in identifying precise biological targets along with their far-reaching implications across various domains, spanning healthcare diagnostics, environmental monitoring, and diverse bioanalytical fields. By exploring these applications, the article highlights the significance of prioritizing the use of natural resources for nanoparticle synthesis. This emphasis aligns with the worldwide goal of envisioning sustainable and customized biosensing solutions, emphasizing heightened sensitivity and selectivity.

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This study explores a smartphone-based spot detection framework for glucose in a rapid, simple, and affordable paper-based analytical device (PAD), which employs machine-learning algorithms to estimate various glucose concentrations. Herein, two different detection mixtures were chosen with chitosan (C) and without chitosan (WC) for the color change analysis. Being a biopolymer, chitosan improves the analytical performance of PADs when used with a chromogenic agent. Moreover, the influence of the illumination conditions and camera optics on the professed color of glucose strips was observed by choosing various illumination conditions and different smartphones. Hence, this study focuses on developing a framework for smartphone-based simple and user-friendly spot-based glucose detection (with a concentration range of 10-40 mM) at any illumination conditions and in any direction of illumination. Additionally, the combination of color spaces and machine-learning algorithms was applied for the signal enhancement. It was observed that the machine learning classifiers, cubic support vector machine (SVM) and narrow neutral network show higher accuracy for the WC samples, which are 92.7 and 92.3%, respectively. The samples with chitosan show higher accuracy for the linear discriminant and quadratic SVM classifiers, which are 94.1 and 93.9%, respectively. Simultaneously, cubic SVM shows ∼93% accuracy for both cases. In order to assess the performance of the devices, a blind test was also conducted. This study demonstrates the potential of the developed system for initial disease screening at the user end. By incorporating machine learning techniques, the platform can provide reliable and accurate results, thus paving the way for estimating the accuracy of the results for improved initial healthcare screening and diagnosis of any disease.

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Recent technological advancements in testing and monitoring instrumentation have greatly contributed to the progress in cancer treatment by surgical, chemotherapeutic and radiotherapeutic interventions. However, the mortality rate still remains high, calling for the development of new treatment strategies with higher efficacy. Extensive efforts driven in this direction have included broadening of early cancer screening and applying innovative theranostic nanotechnologies. They have been supported by platforms introduced to enable the detection and monitoring of cancer biomarkers, inhibitors, and other agents, able to slow down cancer progression and prevent metastasis. Despite of the well-recognized principles of the immune checkpoint blockade, the efficacy of immunotherapy achieved so far does not meet the well-founded expectations. For a successful cancer treatment, highly sensitive, robust, and inexpensive multiplex biosensors have to be designed to aid in the biomarkers monitoring and in the development of new inhibitors. In this review, we provide an overview of the efforts undertaken to aid in the development and monitoring of anticancer immunotherapy, based on the programmed cell-death immune checkpoint (PD-1/PDL-1) blockade, by designing biosensors for the detection of relevant cancer biomarkers and their inhibitors screening. This review also emphasizes alternative targets made by exosomes carrying PD-L1 overexpressed in cancer cells and passed into the excreted exosomes. Evaluated are also novel targeted drug delivery nanocarriers, providing simultaneous biosensing, thereby contributing to the emerging immune checkpoint cancer therapy. On the basis of the current trends and the emerging technologies, future perspectives of cancer diagnostics and treatment monitoring using biosensing platforms are projected.

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Biosensors have rapidly emerged as a high-sensitivity and convenient detection method. Among various types of biosensors, optical and electrochemical are the most commonly used. Conventionally, antibodies have been employed to ensure specific interaction between the transmission material and analytes. However, there has been increasing recognition of peptides as a promising recognition element for biosensor development in recent years. The use of peptides as recognition elements provides high level of specificity, sensitivity, and stability for the detection process. The combination of peptide designs and optical or electrochemical detection methods has significantly improved biosensor efficacy. These advancements present opportunities for developing biosensors with diverse functions that can be used to lay a strong scientific foundation for the development of personalized medicine and various other fields. This paper reviews the recent advancements in the development and application of peptide-based optical and electrochemical biosensors, as well as their prospects as a sensor type.

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The environmental contamination due to bacterial proliferation vs their identification is the major deciding factor in the spread of diseases leading to pandemics. The advent of drug-resistant pathogenic contaminants in our environment has further added to the load of complications associated with their diagnosis and treatment. Obstructing the spread of such infections, prioritizes the expansion of sensor-based diagnostics, effectuating, a sturdy detection of disease-causing microbes, contaminating our surroundings in shortest possible time, with minimal expenditure. Among many sensors known, optical biosensors promote the recognition of pathogens befouling the environment through a comparatively intuitive, brisk, portable, multitudinous, and thrifty approach. This article reviews the recent progresses in optical biosensor-based systems for effective environmental monitoring. The technical and methodological perspectives of fundamental optical-sensing platforms are reviewed, combined with the pros and cons of every procedure. Eventually, the obstacles lying in the path of development of an effective optical biosensor device for bio-monitoring and its future perspectives are highlighted in the present work.

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Microgreens have gained attention for their exceptional culinary characteristics and high nutritional value. The present study focused on a novel approach for investigating the easy extraction of plant samples and the utilization of immersible silicon photonic sensors to determine, on the spot, the nutrient content of microgreens and their optimum time of harvest. For the first time, it was examined how these novel sensors can capture time-shifting spectra caused by the molecules' dynamic adhesion onto the sensor surface. The experiment involved four types of microgreens (three types of basil and broccoli) grown in a do-it-yourself hydroponic installation. The sensors successfully distinguished between different plant types, showcasing their discriminative capabilities. To determine the optimum harvest time, this study compared the sensor data with results obtained through standard analytical methods. Specifically, the total phenolic content and antioxidant activity of two basil varieties were juxtaposed with the sensor data, and this study concluded that the ideal harvest time for basil microgreens was 14 days after planting. This finding highlights the potential of the immersible silicon photonic sensors for potentially replacing time-consuming analytical techniques. By concentrating on obtaining plant extracts, capturing time-shifting spectra, and assessing sensor reusability, this research paves the way for future advancements in urban farming.

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