Biosensor Technique Research Articles

Productive biosensing techniques empowered by all-dielectric metasurfaces

Artificially designed, functional nanostructured surfaces, called metasurfaces, are an emerging platform for biosensing. Two major types of metasurface biosensors have been reported: one is based on resonant-wavelength shift and the other is specialized for fluorescence (FL) detection. The all-dielectric metasurfaces that composed of periodic arrays of silicon nanocolumns have a series of optical magnetic-mode resonances, some of which were found to significantly enhance capability for FL detection of diverse target biomolecules, ranging from nucleic acid to antigens and antibodies. Here, we mainly address the recent advances in productive metasurface FL biosensors, provide an overview of the pivotal results, and discuss the future prospects, including artificial-intelligence-driven big data analysis for the next-generation healthcare services.

Emerging trends in nano-sensors: A new frontier in food safety and quality assurance.

The rapid evolution of nanotechnology has catalyzed significant advancements in the design and application of nano-sensors, particularly within the food industry, where ensuring safety and quality is of paramount concern. This review explores the multifaceted role of nano-sensors constructed from diverse nanomaterials in detecting foodborne pathogens and toxins, offering a comprehensive analysis of their operational principles, sensitivity, and specificity. Nano-sensors leverage unique physical and chemical properties at the nanoscale to enhance the detection of microbial contamination, actively contributing to food safety protocols. With applications ranging from real-time monitoring of pathogenic bacteria, such as Escherichia coli and Salmonella, to assessing environmental factors affecting food quality, these innovative devices demonstrate unparalleled advantages over conventional detection methods. Recent research illustrates the integration of nano-sensors with biosensing techniques, enabling multiplex analysis and rapid detection. Furthermore, the review addresses current challenges in the commercialization and regulatory landscape of nano-sensor technology, emphasizing the need for ongoing research to optimize their performance and facilitate widespread adoption in food safety systems. Overall, the incorporation of nano-sensors represents a transformative approach to safeguarding public health by proactively managing food safety risks and enhancing the efficiency of food quality assurance processes.

Origami-Inspired Biosensors: Exploring Diverse Applications and Techniques for Shape-Changing Sensor Platforms

Biosensors are widely used across industries such as healthcare, food safety, and environmental monitoring, offering high stability and sensitivity compared to conventional methods. Recently, origami—the art of folding 2D structures into 3D forms—has emerged as a valuable approach in biosensor development, enabling the creation of shape-changing devices. These origami-based biosensors are particularly useful in precision medicine, rapid diagnostics, and resource-limited settings, offering affordable, highly precise, and portable solutions with diverse applications. Paper and biological substrates like DNA have been integrated with origami techniques to develop biosensors with enhanced functionality. The incorporation of aptamer origami into both paper and DNA biosensors further increases sensitivity and specificity for target detection. The concept of paper-based origami biosensors originated from using paper as a platform for biological assays, leading to significant advancements in design and functionality. These devices employ folding techniques to create channels and wells for manipulating samples and detecting target molecules through reactions with specific reagents. Similarly, DNA origami, introduced in 2006, has revolutionized biosensors by enabling the creation of precise molecular systems with tunable properties. Paper-based and DNA origami biosensors have immense potential to transform biosensing technologies in healthcare, food safety, and environmental monitoring. This review explores diverse origami-based biosensor techniques and their applications, including the role of aptamer origami in paper and DNA biosensors.

Electrochemical and optical methods for detection of cystatin C as a biomarker of kidney disease.

The kidneys have vital functions in the body, including maintaining homeostasis and blood pressure, controlling water-electrolyte balance, and eliminating metabolic wastes. Early identification of renal dysfunction disease and selection of effective treatment methods reduce mortality in patients. Nowadays, Common indicators of kidney function lack the necessary specificity and sensitivity, but recent studies have reported that cystatin C (CysC) may be an ideal marker for glomerular filtration. CysC, known as a cysteine protease inhibitor, is synthesized by nucleated cells and is easily filtered due to its positive charge and low molecular weight. Also, the synthesis and secretion of CysC is a stable process that is not affected by dietary factors, enhanced protein catabolism, and renal conditions. Various studies have reported that measuring the level of CysC in the body's biological fluids is necessary for the treatment and diagnosis of a wide range of diseases, especially chronic kidney disease (CKD).Despite evidence that positive correlation between the high risk and/or progression of CKD and CysC, it's applied in clinical practice is still rare. Biosensors have been widely developed and researched as an effective method for the pharmaceutical, environmental, and medical fields. Biosensors are designed to create an effective electronic signal commensurate with the concentration of a particular biochemical.Recently, many studies have used biosensor techniques to detect CysC in kidneys and other diseases. In this study, we attempt to examine studies that have used different biosensor techniques for the detect CysC.

Electrochemical Investigations of Chlorpyrifos-Induced Toxicity Effects in Astrocytic Glutamate Regulation

Glutamate is a major excitatory neurotransmitter in the central nervous system, and its homeostasis is critically regulated by astrocytic glutamate transporters. Dysregulation of astrocyte function has been implicated in the pathogenesis of various neurodegenerative diseases. The organophosphate pesticide chlorpyrifos (CPF) has raised significant public health concerns due to its documented neurotoxic effects, but the specific impacts of CPF on glutamate neurotransmission and metabolism within astrocytes remain poorly understood.Here we designed and modified an electrochemical sensor to detect changes in glutamate levels following acute CPF exposure in astrocyte cultures. Our microclinical analyzer (µCA) paired with screen-printed electrodes (SPE) offers an automated sensing system that enables high-resolution monitoring of extracellular glutamate dynamics, providing insights into the effects of CPF on astrocytic glutamate regulation. Immobilized glutamate oxidase on electrode surfaces provided selective and sensitive glutamate detection. The temperature modification of electrodes through incubation (37°C) led to a nearly four-fold improvement in sensitivity (0.84±0.04 nA/µM), with low limits of detection (2.8±0.1 µM), and quantitation (9.3±0.5 µM). Our SPE detected glutamate from 1 to 600 µM which comprehends the physiological range in the brain region. These sensors were used to assess the glutamate uptake efficiency via challenging escalating concentrations of glutamate (10-200 µM) in astrocytes. Glutamate uptake was most efficient when astrocytes were exposed to 50 µM glutamate for 30min (50% net uptake). Efficiencies of glutamate uptake after 24-hour 100 µM CPF exposure were significantly diminished compared with the DMSO control.The results shed light on the potential mechanisms by which CPF-induced disruption of astrocytic glutamate homeostasis may contribute to neurological damage and dysfunction. This work demonstrates the utility of electrochemical biosensing techniques for investigating the neurotoxicological impacts of environmental toxicants on specific cell types and neurochemical pathways. Further development of these analytical tools may aid in elucidating the complex relationships between astrocyte dysregulation, excitotoxicity, and neurodegenerative processes.

Potential Control for Bipolar Electrochemical Systems By Closed Circuits Including Ion-Selective Electrodes

Introduction Bipolar electrode (BPE) is an independent conductor immersed in the electrolyte and without directly connected to the external electronic circuit. Compared with the traditional three-electrode system, a BPE has unique advantages including a simple electrode structure, flexible sensing design, as well as the wireless driving (1). Therefore, in promoting multiplexed electrochemical detection, bipolar electrochemistery provides an effective solution for integrated design. However, given the absence external electronic circuit connection, precise control of the interfacial potential for a single BPE has been an issue in realizing reliable quantitative sensing (2). To solve this problem, we reported a new strategy for highly sensitive potential control of bipolar systems. An ion-selective electrode (ISE) which maintain a stable potential in ISE/solution interface with different ionic strengths coupled with BPE. An electrochemical closed circuit forms by Ag/AgCl electrode bridged BPE and ISE cells. The potential at the BPE/solution interface was controlled based on the potential of ISE and the position of the closed circuit. This technique enables single BPE on a highly array device to achieve sensitive potential control, which promotes the identification of informative biomarkers in large scale and real-time clinical studies. Experiment method Fig. 1 (A) shows the schematic of the closed bipolar system used for illustrating the potential control. The BPEs, ISE, and driving electrodes (Pt) are consolidated on a glass substrate. BPE (Ⅱ) branched out an arm electrode in the middle and modified with Na+ ion-selective membrane (ISM) at the terminal. BPE (Ⅰ) was employed as a control group without potential control unit. Electrochemiluminescence (ECL) was introduced as a powerful biosensing technique for BPE. Adopting the concept of closed BPE, signaling reaction (chemiluminescence) at anode as a reporter for sample reduction at cathode of BPE that can be triggered by electrical potential. These two reactions took place in separate chambers that were only connected through a BPE. In the anodic chamber (red in Fig. 1A), 5 mM tripropylamine (TPA) and 1 mM [Ru(bpy)3]2+ in 100 mM phosphate buffer (PBS) (pH 6.9) was used for ECL reaction. The cathodic chamber was filled with 100 mM PBS (pH 6.9) containing 1 mM KCl (green in Fig. 1A). The ISE chamber (blue in Fig. 1A) was filled with NaCl solution of predetermined concentrations. Given the isolated chambers of BPE, two cases are explored, the ISE chamber and anodic chamber or cathodic chamber are bridged with a silver electrode with AgCl growing at both ends. When a constant voltage is applied into BPE chambers, [Ru(bpy)3]2+/TPA are oxidized on the anodes accompanied by photon emitting. These ECL signals are observed by CCD camera correspond to the reduction of O2 at the cathode due to the current flow through BPE. The different of ECL intensity reveals the situation of potential different at the BPE/solution interface. Results and discussion The closed bipolar system was first characterized with O2 reduction in the cathodic chamber, the curve for ECL intensity with driving voltage moved significantly depending on the location of the Ag/AgCl (Fig. 1 (B)). The peak of ECL was observed under larger driving voltage when the Ag/AgCl coupled the cathodic and control chamber. The effect of using the ISE was also examined by changing the concentration of NaCl in the control chamber. ECL intensity of BPE (Ⅱ) was decreased with the concentration of NaCl when Ag/AgCl connected anodic chamber (Fig. 1 (C)), in converse, ECL increased with NaCl when Ag/AgCl connected cathodic chamber. (Fig. 1 (D)). The results can be explained considering that the interfacial potential differences at both the anodic and cathodic poles shift in a more positive direction under the rate-limiting condition for the anodic pole.Fosdick, S. E., Knust, K. N., Scida, K., & Crooks, R. M., Angewandte Chemie, 52, 40(2013).A. A. Mutalib, Y. Deng, A. Hsueh, K. Kariya,T. Kurihara,H. Suzuki, Electroanalysis, 13, 10(2021). Figure 1

Advanced Bio-sensing Technologies for Sickle Cell Disease Diagnosis.

Sickle cell diseases are widespread in regions encompassing the Mediterranean, Middle East, sub-Saharan Africa, and specific parts of Asia, primarily due to the abnormal production of hemoglobin S. This genetic blood disorder stems from a mutation in the beta-globin gene, a crucial component of hemoglobin and the heme-containing protein found in red blood cells. Point mutations in the hemoglobin gene can be inherited as a heterozygous or homozygous pattern. These mutations disrupt the normal configuration of the protein, impeding its physiological function and altering the cell's shape, giving it a sickle-like appearance. The resulting sickle cells can lead to organ damage, intense physical discomfort, and anemia; in severe cases, the condition can be fatal. Early detection and effective treatment methods have the potential to progressively reduce the associated mortality rate over time. To diagnose sickle cell disease and its carrier states with unparalleled specificity, a variety of approaches have been developed. The most common method includes differential blood cell counts and their assessment, high-performance liquid chromatography (HPLC) and hemoglobin electrophoresis. Furthermore, innovative sensing technologies are currently under development, encompassing user-friendly, cost-effective and portable point-of-care devices that are capable of timely diagnosis at the genetic and molecular levels of these disorders. The review delves into a range of established and innovative strategies utilized in the detection of sickle cell disease, also underscoring the essential role played by diverse bio-sensing techniques in propelling the advancement of early diagnosis of SCD.

Smartphone-deployable and all-in-one machine vision for visual quantification analysis based on distance readout of electrophoresis titration biosensor

As a class of point-of-care (POC) assays with visible distance readout (thermometer style), the electrophoresis titration (ET) biosensor affords high robustness, versatility, and simplicity for point-of-care quantification. However, naked-eye observation of the distance readout is unreliable in POC settings and manual processing of distance readout is time-consuming. Herein, we developed a smartphone-deployable and all-in-one machine vision for four ET biosensors (bovine serum albumin, melamine, uric acid, glutathione) to classify and quantify the samples simultaneously. To ensure accurate and rapid quantification on the smartphone, we customized the decolorization methods and edge detection operators to balance the region of interest (ROI) extraction performance and processing speed. We then established a dataset of 180 distance readout images to endow our machine vision with the ability to classify four sample types. Consequently, our machine vision demonstrated high accuracy in determining the sample type (>97.2%) and concentration (>97.3%). Moreover, expanding its applications to other targets was readily achieved by including distance readout images of other ET biosensors (e.g., hemoglobin A1c) in the dataset. Therefore, our strategy of constructing machine vision is compatible with the versatile ET biosensor technique, suggesting that the same strategy can be used for other thermometer-style POC assays.

Head-area sensing in virtual reality: future visions for visual perception and cognitive state estimation

Biosensing techniques are progressing rapidly, promising the emergence of sophisticated virtual reality (VR) headsets with versatile biosensing enabling an objective, yet unobtrusive way to monitor the user’s physiology. Additionally, modern artificial intelligence (AI) methods provide interpretations of multimodal data to obtain personalised estimations of the users’ oculomotor behaviour, visual perception, and cognitive state, and their possibilities extend to controlling, adapting, and even creating the virtual audiovisual content in real-time. This article proposes a visionary approach for personalised virtual content adaptation via novel and precise oculomotor feature extraction from a freely moving user and sophisticated AI algorithms for cognitive state estimation. The approach is presented with an example use-case of a VR flight simulation session explaining in detail how cognitive workload, decrease in alertness level, and cybersickness symptoms could be modified in real-time by using the methods and embedded stimuli. We believe the envisioned approach will lead to significant cost savings and societal impact and will thus be a necessity in future VR setups. For instance, it will increase the efficiency of a VR training session by optimizing the task difficulty based on the user’s cognitive load and decrease the probability of human errors by guiding visual perception via content adaptation.

Shedding Light on Cellular Secrets: A Review of Advanced Optical Biosensing Techniques for Detecting Extracellular Vesicles with a Special Focus on Cancer Diagnosis.

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.

Design and optimization of refractive index biosensor for MDA-MB-231 and MCF-7 breast cancer biomarker detection

Breast cancer is the leading malignancy in women and the 2nd widespread cancer globally. Earlier identification of breast cancer can improve treatment outcomes and prevent metastasis beyond the breast. Traditional screening tests are not sensitive enough for early diagnosis and have extended detection periods. Recent studies have explored diversified Breast cancer biosensor techniques, including optical, electrical, electrochemical, and mechanical biosensors. This paper nominates a circlet with a large plus sign refraction indices biosensor for the evaluation of two distinct breast cancer cells namely, MDA-MB-231 and MCF-7. The supreme sensitivity has been viewed as 1714.28 nm/RIU for the MDA-MB-231 and 1714.28 nm/RIU for the MCF-7. The supreme quality factor (QF) value for UC1(usual cell of MDA-MB-231) is 10.52, for CC1(cancer cell of MDA-MB-231) is 11.94, for UC2 (usual cell of MCF-7) is 10.64, and for CC2 (cancer cell of MCF-7) is 12.09. The minimal detection value (DL) for UC1 is 0.1573, CC1 is 0.1360, UC2 is 0.1554, and CC2 is 0.1341. This nominated sensor has the potential to sense breast tumor biomarkers.

The Exploration of Nanozymes for Biosensing of Pathological States Tailored to Clinical Theranostics.

The nanozymes (NZs) are the artificial catalyst deployed for biosensing with their uniqueness (high robustness, surface tenability, inexpensive, and stability) for obtaining a better response/miniaturization of the varied sensors than their traditional ancestors. Nowadays, nanomaterials with their broadened scale such as metal-organic frameworks (MOFs), and metals/metal oxides are widely engaged in generating NZ-based biosensors (BS). Diverse strategies like fluorescent, colorimetric, surface-enhanced Raman scattering (SERS), and electrochemical sensing principles were implemented for signal transduction of NZs. Despite broad advantages, numerous encounters (like specificity, feasibility, stability, and issues in scale-up) are affecting the potentialities of NZs-based BS, and thus need prior attention for a promising exploration for a revolutionary outcome in advanced theranostics. This review includes different types of NZs, and the progress of numerous NZs tailored bio-sensing techniques in detecting abundant bio analytes for theranostic purposes. Further, the discussion highlighted some recent challenges along with their progressive way of possibly overcoming followed by commercial outbreaks.

Biosensing Technologies for Detecting Legionella in Environmental Samples: A Systematic Review.

The detection of Legionella in environmental samples, such as water, is crucial for public health monitoring and outbreak prevention. Although effective, traditional detection methods, including culture-based techniques and polymerase chain reaction, have limitations such as long processing times, trained operators, and the need for specialized laboratory equipment. Biosensing technologies offer a promising alternative due to their rapid, sensitive, cost-effectiveness, and on-site detection capabilities. To summarize the current advancements in biosensor development for detecting Legionella in environmental samples, we used 'Legionella' AND 'biosensors' NEAR 'environmental samples' OR 'water' as keywords searching through the most relevant biomedical databases for research articles. After removing duplicates and inadequate articles from the n.1268 records identified using the PRISMA methodology exclusion criteria, we selected n.65 full-text articles which suited the inclusion criteria. Different results between the studies describing the current biosensing techniques, including optical, electrochemical, magnetic, and mass-sensitive sensors were observed. For each biosensing technique, sensitivity, specificity, and detection limits were evaluated. Furthermore, the integration of nanomaterials, microfluidics, and portable devices in biosensor systems' design were discussed, highlighting their role in enhancing detection performance. The potential challenges and future directions in the field of Legionella biosensing were also addressed, providing insights into the feasibility of implementing these technologies in routine environmental monitoring. Undoubtedly, biosensors can play a crucial role in the early detection and management of Legionella infections and outbreaks, ultimately protecting public health and safety.

Advancements in optical biosensing techniques: From fundamentals to future prospects

Optical biosensors that consist of a light source, optical elements, and a photodetector are used to detect chemical and biological species and pollutants. This Tutorial discusses the fundamental details of optical biosensing techniques that include materials, working principle, components, sensor configurations, parameters, and future prospects. Optical biosensing techniques include plasmonic [surface plasmon resonance (SPR) and localized SPR], fluorescence, luminescence, Raman scattering, colorimetric, and interferometric methods. Bioreceptor elements play a significant role in detecting the specific analyte that can be synthetic or natural. Surface functionalization techniques to bind the bioreceptor elements on the surface, to control the bioreceptor orientation, have been discussed in detail. The possibility of integration of techniques on a chip, to develop wearable, implantable sensors, and the associated challenges have been fully demonstrated. This Tutorial provides valuable insights into the present state and future directions of optical biosensors for various applications.

Enhanced pyrophosphate detection: Utilizing oPD-derived carbon dots and Fe3+ interactions in a paper strip biosensor

The development of portable, cost-effective, and straightforward DNA biosensors holds immense importance in various fields, including healthcare, environmental monitoring, and food safety. This study contributes to the objective by introducing an innovative approach for synthesizing carbon dots (Cdots) with high quantum yield (QY) and remarkable selectivity for Fe3+ ions. Utilizing o-phenylenediamine as a precursor, the study achieved a straightforward and environmentally friendly synthesis method, enabling the efficient detachment of metal ions from the Cdot surface upon introducing pyrophosphate (PPi). The presence of surface hydroxyl and amino groups facilitated specific Fe3+ recognition. Employing D-optimal response surface methodology, the study optimized Cdot synthesis parameters, identifying temperature and heating time as critical factors influencing QY. Statistical analysis confirmed the model's reliability, predicting maximum QY of 48.8 % with minimal deviation from experimental results. Characterization studies revealed the amorphous nature of Cdots through HR-TEM, XRD, and FTIR analysis. Furthermore, the proposed LAMP/PPi biosensing technique demonstrated higher sensitivity, specificity, and repeatability, with negligible interference from common anions and efficacy across varying pH levels. The limit of detection (LOD) of 0.079 (±0.01) μM and the detection range of 0.1 μM–2 mM underscore the biosensor's practical utility. This study highlights a promising direction for developing paper-based LAMP/PPi biosensors with potential diagnostics and environmental monitoring applications. Significantly, the biosensing technique is applicable to any DNA amplification method generating pyrophosphate (PPi) as a by-product.

An ultrasensitive electrochemical biosensor with dual-amplification mode and enzyme-deposited silver for detection of miR-205-5p.

An electrochemical biosensor based on dual-amplified nucleic acid mode and biocatalytic silver deposition was constructed using catalytic hairpin assembly-hybrid chain reaction (CHA-HCR). The electrochemical detection of silver on the electrode by linear sweep voltammetry (LSV) can be utilized to quantitatively measure miR-205-5p since the amount of silver deposited on the electrode is proportional to the target nucleic acid. The current response values exhibit strong linearity with the logarithm of miR-205-5p concentrations ranging from 0.1pM to 10μM, and the detection limit is 28 fM. A consistent trend was found in the results of the qRT-PCR and electrochemical biosensor techniques, which were employed to determine the total RNA recovered from cells, respectively. Moreover, the constructed sensor was used to assess miR-205-5p on various cell counts, and the outcomes demonstrated the excellent analytical efficiency of the proposed strategy. Therecoveries ranged from 97.85% to 115.3% with RSDs of 2.251% to 4.869% in human serum samples. Our electrochemical biosensor for miR-205-5p detection exhibits good specificity, high sensitivity, repeatability, and stability. It is a potentially useful sensing platform for tumor diagnosis and tumortype identificationin clinical settings.

(Invited) Electric-Driven Preconcentrating Microfluidic Device for Enhancing Biomolecular Sensing

Preconcentration of biomolecules for detection on microfluidic platforms based on electrical kinetic trapping (EKT) through ion concentration polarization (ICP) has been well developed in the past decade. Biomolecules can be entrapped due to the equilibrium of forces between electro-osmosis and ICP when applying a voltage to the system. In tis study, I will introduce different type of ICPs including theory, mechanism and their limitation. I will also clarify the experimental ICP results based on different microfluidic channel design. A triboelectric nanogenerator (TENG)-driven nanofluidic preconcentrating device that is able to trigger ICP and subsequently cause the EKT of the biomolecules without using a conventional electrical power source was also introduced. The EKT and electrical characteristics of the TENG-based nanofluidic preconcentrator were studied. The preconcentration factors of the device can be found to be ~1000 folds. Several examples of preconcentration device integrating to biosensing techniques are presented in this talk. Some biomarkers are also demonstrated. Further, I will also demonstrate that these biosensors, combining with preconcentrators, can be integrated to a smartphone reader.

Applications of nanostructured materials for severe acute respiratory syndrome-CoV-2 diagnostic

There is a growing concern that severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) infections will continue to rise, and there is now no safe and effective vaccination available to prevent a pandemic. This has increased the need for rapid, sensitive, and highly selective diagnostic techniques for coronavirus disease (COVID-19) detection to levels never seen before. Researchers are now looking at other biosensing techniques that may be able to detect the COVID-19 infection and stop its spread. According to high sensitivity, and selectivity that could provide real-time results at a reasonable cost, nanomaterial show great promise for quick coronavirus detection. In order to better comprehend the rapid course of the infection and administer more effective treatments, these diagnostic methods can be used for widespread COVID-19 identification. This article summarises the current state of research into nanomaterial-based biosensors for quick SARS‑CoV‑2 diagnosis as well as the prospects for future advancement in this field. This research will be very useful during the COVID-19 epidemic in terms of establishing rules for designing nanostructure materials to deal with the outbreak. In order to predict the spread of the SARS-CoV-2 virus, we investigate the advantages of using nano-structure material and its biosensing applications.

Brillouin Biosensing of Viscoelasticity across Phase Transitions in Ovine Cornea.

Noninvasive in situ monitoring of viscoelastic characteristics of corneal tissue at elevated temperatures is pivotal for mechanical property-informed refractive surgery techniques, including thermokeratoplasty and photorefractive keratectomy, requiring precise thermal modifications of the corneal structure during these surgical procedures. This study harnesses Brillouin light scattering spectroscopy as a biosensing platform to noninvasively probe the viscoelastic properties of ovine corneas across a temperature range of 25-64 °C. By submerging the tissue samples in silicone oil, consistent hydration and immiscibility are maintained, allowing for their accurate sensing of temperature-dependent mechanical behaviors. We identify significant phase transitions in the corneal tissue, particularly beyond 40 °C, likely due to collagen unfolding, marking the beginning of thermal destabilization. A subsequent transition, observed beyond 60 °C, correlates with collagen denaturation. These phase transformations highlight the cornea's sensitivity to both physiologically reversible and irreversible viscoelastic changes induced by mild to high temperatures. Our findings underscore the potential of the Brillouin biosensing technique for real-time diagnostics of corneal biomechanics during refractive surgeries to attain optimized therapeutic outcomes.

Research Progress on Detection of Pathogens in Medical Wastewater by Electrochemical Biosensors.

The detection of pathogens in medical wastewater is crucial due to the high content of pathogenic microorganisms that pose significant risks to public health and the environment. Medical wastewater, which includes waste from infectious disease and tuberculosis facilities, as well as comprehensive medical institutions, contains a variety of pathogens such as bacteria, viruses, fungi, and parasites. Traditional detection methods like nucleic acid detection and immunological assays, while effective, are often time-consuming, expensive, and not suitable for rapid detection in underdeveloped areas. Electrochemical biosensors offer a promising alternative with advantages including simplicity, rapid response, portability, and low cost. This paper reviews the sources of pathogens in medical wastewater, highlighting specific bacteria (e.g., E. coli, Salmonella, Staphylococcus aureus), viruses (e.g., enterovirus, respiratory viruses, hepatitis virus), parasites, and fungi. It also discusses various electrochemical biosensing techniques such as voltammetry, conductometry, impedance, photoelectrochemical, and electrochemiluminescent biosensors. These technologies facilitate the rapid, sensitive, and specific detection of pathogens, thereby supporting public health and environmental safety. Future research may should pay more attention on enhancing sensor sensitivity and specificity, developing portable and cost-effective devices, and innovating detection methods for diverse pathogens to improve public health protection and environmental monitoring.