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Micro-opto-electro-mechanical systems (MOEMS) biosensors are employed in various applications such as disease monitoring, drug investigation, detection of pollutants, and biological fluid studies. In this paper, a novel MOEMS biosensor based on a differential folded-flexure structure is introduced. The designed device is employed to detect prostate-specific antigen (PSA) protein and Hepatitis DNA. The target molecules cause a mechanical deflection in the folded-flexure; subsequently, the transmitted optical power across the finger, attached to the flexure, is modulated in proportion to the input concentration. Then, a photodiode power sensor measures the modulated optical power, where the output of the sensor is simply a current related to the target molecules' concentrations. The employed readout circuit operates at a wavelength of λ = 1550 nm with a laser power of 1 µW. The dimensions of the proposed biosensor are considered to be 365 × 340 × 2 μm³, making this sensor small enough and suitable for integration. The designed biosensor provides notable features of mechanical deflection sensitivities of 0.2053 nm/(ng/ml) and 7.2486 nm/nM, optical transmittance sensitivities of 0.535504 × 10−3 1/(ng/ml) and 18.91 × 10−3 1/nM, total output sensitivities of 0.5398 (mA/W)/(ng/ml) and 19.059 (mA/W)/nM, and measurement ranges of 0-1000 ng/ml and 0-28.33 nM for PSA and Hepatitis DNA, respectively. The proposed system is a sensitive and powerful sensor that can play an important role in diagnosing many diseases. [ABSTRACT FROM AUTHOR]

Actinobacteria cells Rhodococcus erythropolis 4-1 and Rhodococcus erythropolis 11-2 and Proteobacteria Alcaligenes faecalis 2, which have amidase activity, were immobilized by entrapping barium alginate and agarose into the gel structure, as well as by obtaining biofilms on thermally expanded graphite (TEG). The operational stability of such immobilized biocatalysts after storage in frozen and dehydrated form was determined, and a prototype of a conductometric acrylamide biosensor based on such a bioselective agent was developed. The most preferred method for storing immobilized cells was freezing at temperatures from –20 to –80°C; long-term storage is also possible wet at 4–25°C. It was shown that these cells were most preferable for the biodetection of acrylamide A. faecalis 2, immobilized in an agarose gel structure. An agarose gel with bacterial cells immobilized in its structure had greater mechanical strength and stability during successive cycles of conversion of acrylamide into acrylic acid compared to barium alginate gel. The mechanical strength of barium alginate gel can be enhanced by the addition of carbon nanomaterials during cell immobilization. Growing biofilms on carbon materials used for manufacturing electrodes is also promising. Biofilms of R. erythropolis 11-2 on TEG are capable of converting acrylamide into acrylic acid in more than 20 reaction cycles while maintaining at least 50% amidase activity. [ABSTRACT FROM AUTHOR]

Nanozymes are a new kind of material which has been applied since the beginning of this century, and its birth has promoted the development of chemistry, materials science, and biology. Nanozymes can be used as a substitute for natural enzyme and has a wide range of applications; therefore, it has attracted extensive attention from all sectors of the community, and the number of studies has constantly increasing. In this paper, we introduced the outstanding achievements in the field of nanozymes in recent years from the main function, the construction of nanozyme-based biosensors, and the treatment of ischemic stroke, and we also illustrated the internal mechanism and the catalytic principle. In the end, the obstacles and challenges in the future development of nanozymes were proposed. [ABSTRACT FROM AUTHOR]

This study developed an innovative biosensor strategy for the sensitive and selective detection of canine mammary tumor biomarkers, cancer antigen 15–3 (CA 15–3) and mucin 1 (MUC-1), integrating green silver nanoparticles (GAgNPs) with machine learning (ML) algorithms to achieve high diagnostic accuracy and potential for noninvasive early detection. The GAgNPs-enhanced electrochemical biosensor demonstrated selective detection of CA 15–3 in serum and MUC-1 in tissue homogenates, with limits of detection (LODs) of 0.07 and 0.11 U mL−1, respectively. The nanoscale dimensions of the GAgNPs endowed them with electrochemically active surface areas, facilitating sensitive biomarker detection. Experimental studies targeted CA 15–3 and MUC-1 biomarkers in clinical samples, and the biosensor exhibited ease of use and good selectivity. Furthermore, ML algorithms were employed to analyze the electrochemical data and predict biomarker concentrations, enhancing the diagnostic accuracy. The Random Forest algorithm achieved 98% accuracy in tumor presence prediction, while an Artificial Neural Network attained 76% accuracy in CA 15–3-based tumor grade classification. The integration of ML techniques with the GAgNPs-based biosensor offers a promising approach for noninvasive, accurate, and early detection of canine mammary tumors, potentially revolutionizing veterinary diagnostics. This multilayered strategy, combining eco-friendly nanomaterials, electrochemical sensing, and ML algorithms, holds significant potential for advancing both biomedical research and clinical practice in the field of canine mammary tumor diagnostics. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) including the superoxide anion (O2•−) are typically studied in cell cultures using fluorescent dyes, which provide only discrete single-point measurements. These methods lack the capabilities for assessing O2•− kinetics and release in a quantitative manner over long monitoring times. Herein, we present the fabrication and application of an electrochemical biosensor that enables real-time continuous monitoring of O2•− release in cell cultures for extended periods (> 8 h) using an O2•− specific microelectrode. To achieve the sensitivity and selectivity requirements for cellular sensing, we developed a biohybrid system consisting of superoxide dismutase (SOD) and Ti3C2Tx MXenes, deposited on a gold microwire electrode (AuME) as O2•− specific materials with catalytic amplification through the synergistic action of the enzyme and the biomimetic MXenes-based structure. The biosensor demonstrated a sensitivity of 18.35 nA/μM with a linear range from 147 to 930 nM in a cell culture medium. To demonstrate its robustness and practicality, we applied the biosensor to monitor O2•− levels in human leukemia monocytic THP-1 cells upon stimulation with lipopolysaccharide (LPS). Using this strategy, we successfully monitored LPS-induced O2•− in THP-1 cells, as well as the quenching effect induced by the ROS scavenger N-acetyl-l-cysteine (NAC). The biosensor is generally useful for exploring the role of oxidative stress and longitudinally monitoring O2•− release in cell cultures, enabling studies of biochemical processes and associated oxidative stress mechanisms in cellular and other biological environments. [ABSTRACT FROM AUTHOR]

This study presents a terahertz (THz) resonance gas sensor design incorporating graphene, black phosphorus, and MXene materials in a metasurface structure. The sensor leverages the unique properties of these advanced two-dimensional materials to achieve enhanced sensitivity and versatility in gas detection applications. The proposed design consists of elliptical and square-shaped resonators arranged on a SiO2 substrate with a ground plane back reflector. Comprehensive simulations using COMSOL Multiphysics were conducted to analyze the sensor's performance across various structural parameters and operating conditions. The sensor demonstrates a maximum sensitivity of 400 GHzRIU−1 and a figure of merit up to 0.816 RIU−1 within a refractive index range of 1–1.07 RIU. Electric field distribution analysis validates the sensor's transmittance response at different frequencies. Notably, the design shows potential for 2-bit encoding applications based on transmittance characteristics under varying graphene chemical potential values. Compared to existing studies, the senso's performance is particularly better in terms of sensitivity, offering advantages such as room temperature operation and fast response times. This research contributes to the advancement of THz sensing technology and opens new possibilities for highly sensitive and versatile gas detection in various applications. [ABSTRACT FROM AUTHOR]

In this paper, an optical refractive index sensor based on a hybrid plasmonic-photonic crystal (P-PhC) topology for detection of various blood components is proposed. The sensor's structure is composed of a gold spiral resonator inside a rod-type hexagonal Si PhC cavity. The finite-difference time-domain method is used for the numerical investigation of the structures. The proposed hybrid sensor provides an astonishing figure of merit (FoM) of 2991 RIU-1 and fairly high sensitivity of 1675 nm/RIU. The maximum FoM achieved in this case is found to be 5 times higher than the conventional plasmonic sensors reported in the literature. For the proposed sensor, combining the stronger plasmonic light-matter interaction and the extraordinary confining properties of the PhC cavity contributes to the FoM enhancement. The proposed sensor can be used for sensing applications at optical communication wavelengths. [ABSTRACT FROM AUTHOR]

A highly selective biosensor for glycine betaine (GB) based on the curcumin derivative (1BHD) is described, which displays a significant visual change and a lower detection limit (76 nM). The GB sensor displays a 1:1 binding ratio and a binding constant of 9.042 × 107 M−1. The binding mechanism of 1BHD for glycine betaine was confirmed by 1H NMR titration, mass spectrometry, and DFT calculation. The fluorescence intensity of 1BHD was selectively quenched by GB, and an obvious color change from yellow to orange was observed by the naked eye. The above results have been utilized to detect GB sensitively in blood and urine samples. [ABSTRACT FROM AUTHOR]

Using a chemiluminescence reaction between luminol and H2O2 in basic solution, an ultrasensitive electrochemiluminescence (ECL) aptasensor was developed for the determination of tobramycin (TOB), as an aminoglycoside antibiotic. Ti3C2/Ni/Sm-LDH-based nanocomposite effectively catalyzes the oxidation of luminol and decomposition of H2O2, leading to the formation of different reactive oxygen species (ROSs), thus amplifying the ECL signal intensity of luminol, which can be used for the determination of TOB concentration. To evaluate the performance of the electrochemiluminescence aptasensor and synthesized nanocomposite, different methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses were performed. The considerable specific area, large number of active sites, and enhanced electron transfer reaction on this nanocomposite led to the development of an ECL aptasensor with high sensitivity and electrocatalytic activity. After optimizing the preparation method and analysis conditions, the aptasensor revealed a wide linear response ranging from 1.0 pM to 1.0 μM with a detection limit of 18 pM, displaying outstanding accuracy, specificity, and response stability. The developed ECL sensor was found to be applicable to the determination of TOB in human serum samples and is anticipated to possess excellent clinical potentials for detecting other antibiotics, as well. [ABSTRACT FROM AUTHOR]

Nile tilapia Oreochromis niloticus is an important aquaculture species worldwide, and understanding its behavior and growth performance under variable culture conditions is essential for optimizing culture. Light as an environmental factor profoundly affects fish development, growth, food consumption, hormone secretion, and other life processes. This study investigated the effects of different light colors (blue, green, and red) on the stress response of individually reared Nile tilapia using a wireless biosensor system for real-time glucose monitoring. The biosensor system effectively measured glucose concentration (stress indicator) by enzymatic oxidation, allowing continuous monitoring of fish eyeball interstitial sclera fluid (EISF), providing longer and more accurate data. Air exposure and ammonia exposure were used as stressors, and stress responses were monitored under different light colors. Nile tilapia exhibited lower quiescent blood glucose levels, lower blood glucose elevations, and faster stress recovery under blue light. Green light induced more significant glucose elevations during acute physical stress, but showed similar fluctuations to blue light during chronic chemical stress, indicating potential benefits for fish welfare. In contrast, whether exposed to air or ammonia, red light induced large fluctuations in blood glucose levels, which may be detrimental to the fish. The study highlights the importance of light color in influencing stress responses and recovery in Nile tilapia, providing valuable insights for improving aquaculture practices and promoting fish welfare. [ABSTRACT FROM AUTHOR]

Modifying electrical and optical properties in two-carbon materials is essential for electronic devices, energy storage and biosensor applications. We report a comparative study of the effect of systematically intercalated strontium atoms in AA- and AB-stacked bilayer graphene (BG) in the framework of density functional theory (DFT). The electronic band structures, the total and partial electronic density of states and the dielectric function are studied. We show that the intercalation of atoms can influence both electronic properties. Our results show that the Dirac cones, a signature of graphene, are translated into the conduction band. This property may be useful in band-gap tuning applications of nanodevices. The optical properties were calculated parallel and perpendicular to the graphene sheet under polarised electric fields. The calculated optical properties show that the intercalation of Sr in the AA- and AB-stacked BGs promotes IR absorption. The findings provide a basis for developing graphene intercalary compounds, which can be used in optoelectronics to control the absorption of light wavelengths and specifically in biosensor applications. [ABSTRACT FROM AUTHOR]

Biosensing for diagnostics has risen rapidly in popularity over the past decades. With the discovery of new nanomaterials and morphologies, sensitivity is being constantly improved enough for reliable detection of trace biomarkers in human samples, like serum or sweat. This precision has enabled detailed research on the efficacy of biosensors. However, current biosensors suffer from reduced speed of operation. To make better use of this sensitivity, the development of a conductometric biosensor with in-situ use of an Laser Emitting Device (LED) display can provide rapid determination of sample results, steadily pushing biosensors toward more clinical, point-of-care (POC) applications. In this research, a simple LED was used for facile optical determination and visual output of an ultrasensitive bio-signal amplification circuit was made to interface with a B-type Natriuretic Peptide (BNP) biosensor. Tuning circuit gain enables an elegant method for adjustable separation of concentrations into 3 discrete categories: sub-threshold, analog, and saturation regions. These regions corresponded to 0 < [C] < 500 pg/mL (25, 100, 250 pg/mL, LED off), 500 < [C] < 1000 pg/mL (LED varying intensity), and 1000 pg/mL < [C] (LED full intensity). System efficacy was tested using human blood serum samples from University of Pittsburgh Medical Center patients, which were able to be accurately detected and sorted for rapid low cost and power. determination without need for complex digital elements. Additional specificity testing suggests insignificant impact of non-target biomarkers. [ABSTRACT FROM AUTHOR]

This study observes the MOSFET's performance concerning several biomolecules for use as a biosensor device. The double gate MOSFET with gate stack configuration has been chosen as the suggested device to surpass the limitations of short-channel effects (SCEs). The cavity was created to restrict the passage of charged and uncharged biological molecules so that they could be detected. These molecules fill the cavity, changing the device's electrical properties. The Double Gate MOSFET (DG-MOSFET) biosensor is subject to limitations such as Short Channel Effects (SCEs) and issues with the power supply. The suggested device decreased SCEs and it also demonstrates the potential benefits of having DG-MOSFETs with gate stacking for biosensor applications. Comparison of transconductance, the generating factor for transconductance, and sensitivity parameters such as Id and Vth sensitivity and Ion/Ioff sensitivity has been carried out in this study.Article Highlights: The variation of temperature can influence the mobility of charge carriers within the semiconductor, affecting the conductance of the sensor. Depending on the specific biomolecule being detected, changes in temperature can modulate the interaction between the biomolecule and the sensor surface, leading to alterations in the electrical properties of the device and these changes can be precisely measured, thereby enhancing the sensitivity of detection. By systematically varying the temperature, researchers can explore the thermodynamic and kinetic aspects of the binding events, allowing for fine-tuning of the sensor performance to meet specific application requirements. [ABSTRACT FROM AUTHOR]

For the first time, a new configuration of label-free junctionless semiconductor device is proposed to boost sensitivity in the identification of biomolecule specifies. Instead of creating the nanocavity inside the gate oxide, the nanocavity is created in the channel region which is very useful for the SOI junctionless technology based biodevice having a high current in all operating modes. For better control of the conduction mechanism, a hole trench is created under the channel region just inside the buried oxide. This will help to modulate the energy bands terminating in enhancing the sensing performance. Unlike the conventional biosensors needing a large-scale gate oxide thickness for trapping the biomolecules, the proposed biosensor can work for very low gate oxide thickness. The different biomolecules such as Biotin, Protein A, Bacteriophage T7, and Apomyoglobin have been utilized as targeted biomolecules for evaluating the sensitivity. Comparing the proposed biosensor with the conventional and other biosensors showed an enhanced sensing performance. Practical related issues during the process of sensing in terms of fill factor percentage, steric hindrance of biomolecules, and the charges of biomolecules have been focused in the recommended biodevice. All the results exhibited high superiority of performance of the suggested biodevice as compared to the conventional biosensor. [ABSTRACT FROM AUTHOR]

CRISPR-based (Clustered regularly interspaced short palindromic repeats-based) technologies have revolutionized molecular biology and diagnostics, offering unprecedented precision and versatility. However, challenges remain, such as high costs, demanding technical expertise, and limited quantification capabilities. To overcome these limitations, innovative microfluidic platforms are emerging as powerful tools for enhancing CRISPR diagnostics. This review explores the exciting intersection of CRISPR and microfluidics, highlighting their potential to revolutionize healthcare diagnostics. By integrating CRISPR's specificity with microfluidics' miniaturization and automation, researchers are developing more sensitive and portable diagnostic tools for a range of diseases. These microfluidic devices streamline sample processing, improve diagnostic performance, and enable point-of-care applications, allowing for rapid and accurate detection of pathogens, genetic disorders, and other health conditions. The review discusses various CRISPR/Cas systems, including Cas9, Cas12, and Cas13, and their integration with microfluidic platforms. It also examines the advantages and limitations of these systems, highlighting their potential for detecting DNA and RNA biomarkers. The review also explores the key challenges in developing and implementing CRISPR-driven microfluidic diagnostics, such as ensuring robustness, minimizing cross-contamination, and achieving robust quantification. Finally, it highlights potential future directions for this rapidly evolving field, emphasizing the transformative potential of these technologies for personalized medicine and global health. [ABSTRACT FROM AUTHOR]

This study introduces a novel biosensor utilizing silver (Ag)–dielectric–black phosphorus (BP) as the foundation to analyze the surface plasmon resonance (SPR) system for alcohol detection for the first time. Silver (Ag) is employed as a metallic layer in the Kretschmann configuration of the proposed sensor to induce the generation of surface plasmons. The present study employs dielectric materials, namely lithium titanate (LiTiO3), potassium tantalite (KTaO3), bismuth silicon oxide (BSO), and zinc selenide (ZnSe), to safeguard the Ag material from oxidation. Additionally, 2D material of BP is used to augment the detecting capacity of the sensor. This study focuses on the detection of ethyl alcohol (ethanol) and propanol alcohol. To analyze the sensor's performance, the transfer matrix method is used with the help of angular interrogation technique. The proposed sensor performance is significantly enhanced by achieving a maximum sensitivity of 277.63°⁄RIU, a detection accuracy of 4.37, and a quality factor of 97.06 RIU - 1 for the optimized sensor design. Hence, the sensor has significant utility in the field of biological applications. [ABSTRACT FROM AUTHOR]

In this article, we have introduced an innovative sensor configuration employing a metasurface encompassing three rectangles configured into a star-shaped structure and multiple square-graphene elements—for accurate blood analysis. The suggested sensor architecture, characterized by its hierarchical structural configuration, offers several advantages crucial for accurate and reliable detection of target biomolecules. The star-shaped pattern, meticulously constructed with specific dimensions, significantly increases the surface area exposed to target compounds, thereby enhancing sensor sensitivity. Forensic science is at the core of investigations into crimes. It is undoubtedly crucial to modern legal structures. It is a constantly growing field that is always looking for new ways to increase the level of accuracy, sensitivity, and effectiveness of evidence examination. Terahertz (THz) spectra have recently developed as a sophisticated method with incredible potential in every aspect of forensics. A critical component of this endeavor is the development of THz sensors capable of detecting hemoglobin, a crucial protein in the evaluation of blood. The proposed sensor displays a remarkable level of sensitivity, with a maximum value of 300 GHzRIU−1 and a detection limit of 1.013 RIU−1. Moreover, the sensor demonstrates its capacity to detect subtle variations through its resolutions and Figure of Merit (FOM), quantified respectively as 0.268 and 1.796 RIU−1. [ABSTRACT FROM AUTHOR]

An innovative photonic crystal fiber (PCF) biosensor using surface plasmon resonance (SPR) to diagnose six distinct kinds of cancers (skin cancer, cervical cancer, adrenal gland cancer, blood cancer, and breast cancer types 1 and 2) in cells is demonstrated here and incorporates with two microchannels and a bimetallic configuration. The numerical analysis utilizes the finite element method (FEM) combined with perfectly matched layers (PML). The plasmonic material employed in the biosensor is gold (Au), and a supportive material, titanium dioxide (TiO2), is combined with Au. By combining these two materials, the sensor's performance is improved. The numerical calculations indicate that breast cancer type 2 has the highest wavelength sensitivity (24,285.71 nm/RIU) and amplitude sensitivity (3959 RIU−1). The rest of the cancer cells' wavelength sensitivities are 11,000.00 nm/RIU (skin cancer), 13,333.33 nm/RIU (cervical cancer), 15,000.00 nm/RIU (blood cancer), 17,142.85 nm/RIU (adrenal gland cancer), and 21,428.57 nm/RIU (breast cancer type 1). This advanced biosensor has several uses in biological sensing and medical technology, and it has the potential to revolutionize cancer identification and medical diagnosis. [ABSTRACT FROM AUTHOR]

Transferrin (TRF), recognized as a glycoprotein clinical biomarker and therapeutic target, has its concentration applicable for disease diagnosis and treatment monitoring. Consequently, this study developed boronic acid affinity magnetic surface molecularly imprinted polymers (B-MMIPs) with pH-responsitivity as the "capture probe" for TRF, which have high affinity similar to antibodies, with a dissociation constant of (3.82 ± 0.24) × 10−8 M, showing 7 times of reusability. The self-copolymerized imprinted layer synthesized with dopamine (DA) and 3-Aminophenylboronic acid (APBA) as double monomers avoided nonspecific binding sites and produced excellent adsorption properties. Taking the gold nanostar (AuNS) with a branch tip "hot spot" structure as the core, the silver-coated AuNS functionalized with the biorecognition element 4-mercaptophenylboronic acid (MPBA) was employed as a surface-enhanced Raman scattering (SERS) nanotag (AuNS@Ag-MPBA) to label TRF, thereby constructing a double boronic acid affinity "sandwich" SERS biosensor (B-MMIPs-TRF-SERS nanotag) for the highly sensitive detection of TRF. The SERS biosensor exhibited a detection limit for TRF of 0.004 ng/mL, and its application to spiked serum samples confirmed its reliability and feasibility, demonstrating significant potential for clinical TRF detection. Moreover, the SERS biosensor designed in this study offers advantages in stability, detection speed (40 min), and cost efficiency. The portable Raman instrument for SERS detection fulfills the requirements for point-of-care testing. [ABSTRACT FROM AUTHOR]

Here, we envisage the development of the rapid, reliable, and facile electrochemical sensor for the primary detection of xanthine (Xn) which is significant for the food quality measurement, based on the silver-doped molybdenum disulfide (Ag@MoS2) nanosheets. The structural and compositional properties of the prepared samples were tested through X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and X-ray photon spectroscopy (XPS). The two-dimensional (2D) MoS2 nanosheets provide the large surface area for the sensing applications and the silver ions help in the enhanced electrochemical response. The fabricated enzymatic biosensor exhibits magnificent cyclic stability with a limit of detection of 27 nM. Also, the sensor was tested for rapid, reproducible, specific, and regenerable up to 10 cycles and has a shelf life of 2 weeks. The outcomes of this study suggest that the proposed matrix could be employed for the fabrication of devices for early detection of xanthine. [ABSTRACT FROM AUTHOR]

Water toxicity determination with electrochemically active bacteria (EAB) shows promise for providing early warnings for heavy metal pollution in water. However, thus far, only idealized tests with a few types of heavy metals have been conducted. In this study, an automatic water-toxicity-determination system with high technical maturity was established, and the toxicological properties of common heavy metals were systematically assessed. The results demonstrated that the common heavy metals linearly inhibited EAB currents in the range of 0.1 mg/L to 0.5 mg/L. The toxicity ranking of the tested heavy metals was Pb2+ > Tl3+ > Cu2+ > Cd2+ > Zn2+ > Ni2+ > Hg2+ > As2+. The toxicity interaction mainly exhibited an antagonistic effect in binary heavy metal mixtures. The system can accurately determine surface water toxicity and rapidly monitor heavy metal pollution, with good repeatability and a long lifetime. Overall, this study demonstrates that EAB are capable of long-term (> 60 d) surface water quality monitoring and on-site early warning of heavy metal pollution. [ABSTRACT FROM AUTHOR]

In this study, a novel dual-core photonic crystal fiber sensor based on surface plasmon resonance is proposed for cancer detection in various parts of the human body. The proposed sensor is designed with a simplified circular geometrical structure with two different sizes of air holes. A gold thin film is placed on the on the cladding of the photonic crystal fiber. The performance of the proposed sensor is demonstrated by applying full vectorial finite element method. The confinement loss and amplitude sensitivity are calculated for the different normal and cancer cells. The proposed sensor has the amplitude sensitivity 595 RIU−1 for the skin cancer and wavelength sensitivity 16,285 nm/RIU for the Adrenal Gland cancer. Furthermore, the proposed cancer sensor achieved the highest Figure of Merit of 571.4 RIU−1. The numerical results indicate that the suggested biosensor could detect cancer cells. Finally, we investigate the fabrication tolerance on the confinement loss and amplitude sensitivity. [ABSTRACT FROM AUTHOR]

Airborne microorganisms pose a significant health threat, causing various illnesses. Traditional detection methods are often slow and complex. This review highlights the potential of nanomaterial-based biosensors, particularly colorimetric sensors, for rapid and on-site detection of airborne microbes. Colorimetric sensors offer real-time visual detection without complex instrumentation. We explore the integration of these sensors with Lab-on-a-Chip technology using PDMS microfluidics. This review also proposes a novel PDMS-based colorimetric biosensor for real-time detection of airborne microbes. The sensor utilizes a color change phenomenon easily observable with the naked eye, simplifying analysis and potentially enabling point-of-care applications. [ABSTRACT FROM AUTHOR]

This paper proposes a surface plasmon resonance (SPR) biosensor based on the Kretschmann configuration including a bilayer of silver metal (Ag), molybdenum disulfide (MoS2), molybdenum trioxide (MoO3), titanium carbide MXene (Ti3C2Tx), and a BK7 coupling prism. The proposed device is designed as a refractive index sensor for hemoglobin measurement in human blood samples. The finite difference time domain (FDTD) technique has been used to evaluate the performance parameters of the sensor. Silver metal and 2D material thickness is optimized using an angular interrogation technique to minimize reflectance. The proposed biosensor exhibits the maximum sensitivity (S) of 218 deg/RIU, at a sensing medium of 1.32919–1.34919 with Δns = 0.005 RIU. Other parameters a detection accuracy of 0.182 deg−1, a figure of merit of 40.63 RIU−1, and a limit of detection of 4.587 × 10–6 have been obtained. The proposed SPR biosensor effectively increases the strength of the interaction between the incident light and the analyte, resulting in a relatively reduced propagation loss. Therefore, the suggested sensor is a suitable candidate to detect and analyze biomolecules. [ABSTRACT FROM AUTHOR]

A Pyrococcus furiosus Argonaute (PfAgo)-based biosensor is presented for alkaline phosphatase (ALP) activity detection in which the ALP-catalyzed hydrolysis of 3′-phosphate-modified functional DNA activates the strand displacement amplification, and the amplicon mediates the fluorescent reporter cleavage as a guide sequence of PfAgo. Under the dual amplification mode of PfAgo-catalyzed multiple-turnover cleavage activity and pre-amplification technology, the developed method was successfully applied to ALP activity determination with a detection limit (LOD) of 0.0013 U L−1 (3σ) and a detection range of 0.0025 to 1 U L−1 within 90 min. The PfAgo-based method exhibits satisfactory analytic performance in the presence of potential interferents and in complex human serum samples. The proposed method shows several advantages, such as rapid analysis, high sensitivity, low-cost, and easy operation, and has great potential in disease evolution fundamental studies and clinical diagnosis applications. [ABSTRACT FROM AUTHOR]

The design of surface plasmon resonance (SPR) sensors has been greatly enhanced in recent years by the advancements in the production and integration of nanostructures, leading to more compact and efficient devices. There have been reports of novel SPR sensors having distinct nanostructures, either as signal amplification tags like gold nanoparticles (AuNPs) or as sensing substrate-like two-dimensional (2D) materials including graphene, transition metal dichalcogenides (TMDCs), MXene, black phosphorus (BP), metal-organic frameworks (MOFs), and antimonene. Such 2D-based SPR biosensors offer advantages over conventional sensors due to significant increases in their sensitivity with a good figure of merit and limit of detection (LOD). Due to their atomically thin structure, improved sensitivity, and sophisticated functionalization capabilities, 2D materials can open up new possibilities in the field of healthcare, particularly in point-of-care diagnostics, environmental and food monitoring, homeland security protection, clinical diagnosis and treatment, and flexible or transient bioelectronics. The present study articulates an in-depth analysis of the most recent developments in 2D material–based SPR sensor technology. Moreover, in-depth research of 2D materials, their integration with optoelectronic technology for a new sensing platform, and the predicted and experimental outcomes of various excitation approaches are highlighted, along with the principles of SPR biosensors. Furthermore, the review projects the potential prospects and future trends of these emerging materials-based SPR biosensors to advance in clinical diagnosis, healthcare biochemical, and biological applications. [ABSTRACT FROM AUTHOR]

Nerve agents, including organophosphorus compounds such as paraoxon, are potent and highly toxic chemicals with grave implications for human health and the environment. In this paper, we present the development of a novel enzyme inhibition-based biosensor for the sensitive and selective detection of paraoxon, which is commonly used as a surrogate for nerve agents. The biosensor employs reduced graphene oxide as a screen-printed electrode surface modification nanomaterial, leading to increased surface electroactivity and, thus, more sensitive detection. The biosensor exhibits a low detection limit of 0.56 pg/ml (limit of detection, LOD) and 1.25 pg/ml (limit of quantification, LOQ), highlighting its high sensitivity for trace-level analysis of nerve agents in complex sample matrices. Our biosensor demonstrates remarkable selectivity for paraoxon, with minimal interference from other non-target chemicals. Stability and repeatability tests reveal that the system maintains its performance integrity over a 45-day period and consistently produces readings with a margin of error of only 5%. Real sample testing in river water, wastewater, and tap water further confirms the biosensor's practical utility, with recovery percentages ranging from 84 to 115%. This biosensor represents a significant advancement in biosensor technology, facilitating the rapid, cost-effective, and reliable detection of toxic substances in real-world scenarios. [ABSTRACT FROM AUTHOR]

An optical biosensor designed using a Nanocomposite/Defect/Nanocomposite multilayer 1D photonic crystal is proposed for malaria diagnosis. The defect layer represents blood samples corresponding to various stages of malaria. Employing the Transmission Matrix Method (TMM), we analyse the impact of two kind of nanocomposite (NC) layers: silver-doped TiO2 and silver-doped SiO2. Comparative analyses involving varying thickness and fill factor of NC layers indicate increased sensitivity with higher fill factors and thickness, albeit with a decrease in transmission. Further, we explore the influence of incident angle (TM & TE mode) on sensing performance, revealing enhanced sensitivity at higher angles. The maximum sensitivity peaks are reported to be 1074 nm/RIU and 1064 nm/RIU for the mentioned NC layer cases. This biosensor promises enhanced sensitivity and potential for advanced malaria diagnostics. [ABSTRACT FROM AUTHOR]

Biosensors are analytical devices for detecting a wide range of targets, including cells, proteins, DNA, enzymes, and chemical and biological compounds. They mostly rely on using bioprobes with a high binding affinity to the target for specific detection. However, low specificity and effectiveness of the conventional biosensors has led to the search for novel materials, that can specifically detect biomolecules. Aptamers are a group of single-stranded DNA or RNA oligonucleotides, that can bind to their targets with high specificity and serve as effective bioprobes for developing aptamer-based biosensors. Aptamers have a shorter production time, high stability, compared to traditional bioprobes, and possess ability to develop them for specific target molecules for tailored applications. Thus, various aptasensing approaches, including electrochemical, optical, surface plasmon resonance and chip-dependent approaches, have been investigated in recent times for various biological targets, including foodborne pathogens. Hence, this article is an overview of various conventional foodborne pathogen detection methods, their limitations and the ability of aptamer-based biosensors to overcome those limitations and replace them. In addition, the current status and advances in aptamer-based biosensors for the detection of foodborne pathogens to ensure food safety were also discussed. [ABSTRACT FROM AUTHOR]

In this work, a novel Ferroelectric gate oxide along with high-k dielectric HfO2 is introduced in the Vertical TFET structure to incorporate the negative capacitance effect. The effects of ferroelectric gate oxide in addition with SiGe heterojunction pocket at source-channel junction improve the performance of the device for biosensor application. A negative capacitance (NC) effect is produced by adding the FE layer over HfO2 by EOT (equivalent oxide thickness), which enhances overall capacitance with reduced SS and OFF current. An n + doped of SiGe material pocket at source channel junction will improve the BTBT of the charge carriers due to low band gap SiGe material. For the Biosensing application of this device, a cavity is added above the source channel junction and below the FE layer, in parallel to HfO2. The integration of bio-molecules their charge density (qf), and their dielectric constant (k), collectively modulates the effective dielectric constant of the gate oxide and hence causes a change in the surface potential and drain current though which the sensitivity of the bio-molecules is determined. The impact of the temperature and cavity length variation is also analyzed on the sensitivity determination. A comparative analysis of ferroelectric VTFET vs non ferroelectric vertical TFET and TFET has been done for bio-sensing application with reference to characteristics like drain current, electric field and surface potential. The highest ON current value recorded for FE-VTFET as 1.02169 × 10–4 (A/µm) whereas normal VTFET has 7.56141 × 10–5 for the bio-molecules having relative dielectric constant is k = 12. The results shows that the negative capacitance improves sensitivity of labeled and label free biosensors significantly. [ABSTRACT FROM AUTHOR]

Osteoporosis (OP) constitutes a notable disorder within bone metabolism, characterized by the creation or desorption of porous bone. Osteocalcin (OC), a marker expressed by osteoblasts at various developmental stages, serves as a pivotal biomarker for diagnosing and monitoring osteoporosis. Current methodologies for quantifying OC, such as enzyme-linked immunosorbent assay (ELISA) and analogous antibody-based techniques, suffer from drawbacks including suboptimal thermostability, diminished sensitivity, and elevated manufacturing costs. In this study, a biosensor was engineered for the precise determination of OC, by using the osteocalcin-specific biorecognition receptor Gpr158 for the first time in the literature. A gold nanoparticle-modified gold screen-printed electrode was used as a working electrode, and electrochemical impedance spectroscopy (EIS) was employed as the primary measurement technique as a label-free method. To enhance system sensitivity, the working electrode was modified with fullerene, a carbon-based spherical nanomaterial. Subsequently, the electrode was immersed in sulfuric acid, activating the carbonyl structures on the fullerene, and through EDC/NHS the biorecognition receptor was immobilized with an amide bond. The efficacy of each modification step was evaluated using EIS and scanning electron microscopy (SEM). EIS was also utilized as an indicator method to analyze OC, revealing a linear determination range spanning from 0.5 to 100 ng/mL. The limits of detection (LOD) and quantification (LOQ) were calculated to be 0.51 ng/mL and 1.53 ng/mL, respectively. The biosensor, characterized by exceptional reproducibility, consistently yielded accurate results in the measurement of osteocalcin. This innovative approach holds promise as a robust and efficient means for diagnosing and monitoring osteoporosis, showcasing its potential as a valuable tool in clinical applications. [ABSTRACT FROM AUTHOR]

In this work, a multispectral aptasensor structure, including a sub-layer and two side walls, was presented. The cells are positioned at the down and top of the structure, with the down cells oriented perpendicular to the walls and the top cells aligned parallel to the walls. The validity of the findings was verified by the utilization of a numerical simulation technique known as 3D Finite Difference Time Domain (FDTD). The biosensor under consideration exhibits sensitivities of 1093.7 nm/RIU, 754 nm/RIU, and 707.43 nm/RIU in mode III, mode II, and mode I, respectively. In the majority of instances, the quantity of analyte available is insufficient to coat the surface of the sensor thoroughly. Consequently, in this study, the evaluation of surface sensitivity was undertaken alongside bulk sensitivity. The surface sensitivity of the suggested structure for mode II in the sensor layer, with thicknesses of 10, 20, 30, and 70 nm, is measured to be 25, 78, 344, and 717.636 nm/RIU, respectively. Our design incorporates a unique arrangement of sub-layer and side walls, with cells positioned to maximize interaction with the target analyte. This innovative configuration, combined with Ag for its superior plasmonic properties, enables the detection of E. coli O157 with remarkable sensitivity. [ABSTRACT FROM AUTHOR]

This review elucidated the recent advances in integrating microalgal communities in monitoring metal pollution in aquatic ecosystems of sub-Saharan Africa (SSA). It also highlighted the potential of incorporating microalgae as bioindicators in emerging technologies, identified research gaps, and suggested directions for further research in biomonitoring of metal pollution. Reputable online scholarly databases were used to identify research articles published between January 2000 and June 2023 for synthesis. Results indicated that microalgae were integrated either individually or combined with other bioindicators, mainly macroinvertebrates, macrophytes, and fish, alongside physicochemical monitoring. There was a significantly low level of integration (< 1%) of microalgae for biomonitoring aquatic metal pollution in SSA compared to other geographical regions. Microalgal communities were employed to assess compliance (76%), in diagnosis (38%), and as early-warning systems (38%) of aquatic ecological health status. About 14% of biomonitoring studies integrated microalgal eDNA, while other technologies, such as remote sensing, artificial intelligence, and biosensors, are yet to be significantly incorporated. Nevertheless, there is potential for the aforementioned emerging technologies for monitoring aquatic metal pollution in SSA. Future monitoring in the region should also consider the standardisation and synchronisation of integrative biomonitoring and embrace the "Citizen Science" concept at national and regional scales. [ABSTRACT FROM AUTHOR]

A voltammetric DNA sensor is developed for the determination of doxorubicin, the signal of which is the change in the current of the redox mediator Methylene green, recorded by cyclic voltammetry on a glassy carbon electrode modified by electrochemically reduced graphene oxide, electropolymerized Azure A, and DNA saturated with Methylene green. The influence of the nature of the polymer layer and the redox mediator used on the sensitivity of the determination of doxorubicin is revealed. With an optimal composition of the surface layer, the DNA sensor allows the determination of up to 0.01 pM of doxorubicin. The sensor was tested on a number of model (artificial urine, Ringer−Locke solution, bovine serum albumin solution) and biological samples (saliva, urine) containing doxorubicin. [ABSTRACT FROM AUTHOR]

Purpose: Waterborne pathogens pose a significant threat to public health, emphasizing the continuous necessity for advancing robust detection techniques, particularly in preventing outbreaks associated with these pathogens. This study focuses on cholera, an infectious disease caused by Vibrio cholerae, serogroups O1 and O139, often transmitted through contaminated water and food, raising significant public health concerns in areas with poor sanitation and limited access to clean water. Methods: We developed a colorimetric biosensor using aptamer-functionalized gold nanoparticles to identify Vibrio cholerae O139 and address this issue. The detection mechanism relies on the color change of gold nanoparticles (AuNPs) from red to blue-purple induced by NaCl after the pathogen incubation and aptamer-target binding. Initial steps involved synthesizing and characterizing AuNPs, then exploring the impact of aptamer and NaCl concentrations on AuNP agglomeration. Optimization procedures for aptamer concentration and salt addition identified the optimal conditions for detection as 120 pM aptamers and 1 M NaCl. Results: The aptasensor demonstrated a robust linear relationship, detecting V. cholerae concentrations from 103 to 108 CFU/mL, with a limit of detection (LOD) of 587 CFU/mL. Specificity tests and accurate sample analyses confirmed the efficiency of the AuNPs aptasensor, showcasing its reliability and speed compared to traditional culture examination methods. Moreover, we extended the aptasensor to a paper-based sensing platform with similar detection principles. Conclusion: The change in color upon target binding was captured with a smartphone and analyzed using image processing software. The paper-based device detected the target in less than 2 min, demonstrating its convenience for on-field applications. [ABSTRACT FROM AUTHOR]

Hemoglobin in a blood sample has been analyzed for the diagnosis of anemia cancer in a human's body by using metal/defect/metal multilayer one-dimensional (1D) photonic crystals. The proposed structure contains five periodic layers of Si/BaF2 and a very thin defect layer of blood sample between two thin metal layers of Ag. In this case, a low concentration of hemoglobin in red blood cells (RBC) which is a function of refractive index indicates anemia cancer in the patient. The modification of the refractive index or concentration simply causes a shift in the transmittance of the defect mode in the photonic bandgap, which can be used for anemia diagnosis. To analyze the transmittance properties, the thickness of a metal layer, angle of incidence, and refractive index/concentration of the defect layer have been varied by using the transfer matrix method. It is analyzed that the shifting of the transmission peak has been improved further with an increase in metal layer thickness and incident angle. Detailed analysis shows that the proposed device contains a quality factor of 990 and a sensitivity of 892.85 nm/RIU. Detailed analysis shows that the proposed device demonstrates very high sensitivity when the defective layer is placed between two metal layers. So the proposed device may have potential applications in biosensing. [ABSTRACT FROM AUTHOR]

We proposed the numerical studies and machine learning prediction for the multilayered Borophene-GST-silica-Ag-based refractive index sensor for the 1.3–1.5 µm wavelength range. The top layers of the proposed sensor incorporate Ag gratings. The proposed structure utilizes a mode based on surface plasmonic resonance, which has been created using a finite element model through computational analysis. Resonance is observed across a range of refractive index values from 1 to 2.5, which primarily aligns with the refractive indices of key biomolecules such as haemoglobin, saliva, urine, and cancerous cells. The proposed structure has also been investigated for the different physical parameters such as material height, grating space, the incident wave's wide incident angle, and the GST material's phase. We demonstrate the modulation of reflectance values in response to varying phases of the GST material (amorphous and crystalline), which can be controlled through external temperature changes. The distribution of the electric and magnetic fields of the structure is also provided in order to examine the field distribution across the grating and other layers of material. This sensor offers a wide angle of stability (0 to 80°) for the respective resonating points. An artificial neural network is employed to analyze the simulated data and make predictions regarding the behaviour of the structure. We have found the R2 = 0.97 for the proposed artificial neural network (ANN) model. The ANN model of this structure also presented the values of mean square error (MSE), mean absolute error (MAE), and root mean square error (RMSE) for different epoch values. Results shown in this research can help to sense the wide range of biomolecule samples whose refractive index ranges from 1 to 2.5. The wide wavelength range makes this device applicable for developing wideband infrared biosensors. [ABSTRACT FROM AUTHOR]

Electrogenerated chemiluminescence (ECL) stands out as a remarkable phenomenon of light emission at electrodes initiated by electrogenerated species in solution. Characterized by its exceptional sensitivity and minimal background optical signals, ECL finds applications across diverse domains, including biosensing, imaging, and various analytical applications. This review aims to serve as a comprehensive guide to the utilization of ECL in analytical applications. Beginning with a brief exposition on the theory at the basis of ECL generation, we elucidate the diverse systems employed to initiate ECL. Furthermore, we delineate the principal systems utilized for ECL generation in analytical contexts, elucidating both advantages and challenges inherent to their use. Additionally, we provide an overview of different electrode materials and novel ECL-based protocols tailored for analytical purposes, with a specific emphasis on biosensing applications. [ABSTRACT FROM AUTHOR]

A robust "on–off" fluorescent aptasensor was developed using nanohybrids of molybdenum sulfide (MoS2) quantum dot (QD)–doped zinc metal–organic frameworks (Zn-MOF) for selective and sensitive detection of cadmium ions (Cd2+) in water. This nanohybrid (MoS2@Zn-MOF), synthesized via "bottle around the ship" methodology, exhibited a high-intensity fluorescence emission centered at 430 nm (λEm) (blue) on excitation at 320 nm (λEx). Further, the conjugation of this fluorophore to phosphate-modified cadmium aptamer (Cd-2–2) was achieved through carbodiimide reaction. The hybridization of prepared sensing probe (MoS2@Zn-MOF/Cd-2–2 aptamer) was done with dabcyl-conjugated complementary DNA (cDNA), acting as energy donor–acceptor pair in the fluorescence resonance energy transfer (FRET) system. This hybridization causes the fluorescence quenching of the nanohybrid. In the presence of Cd2+, the aptamer from the fabricated nano-biosensing probe binds to these ions, resulting in release of dabcyl-cDNA oligomer. This release of dabcyl-cDNA oligomer from the sensing probes restores the fluorescence of the nanohybrid. Under optimized conditions (sensing probe/dabcyl-cDNA ratio 1/7, pH 7.4, and temp 28 °C), the sensing probe showed a fast response time of 1 min. The fluorescence intensity of the nanohybrid can be utilized to determine the concentration of Cd2+. The proposed aptasensor achieved highly sensitive detection of Cd2+ with a limit of detection (LOD) of 0.24 ppb over the range of 1 × 10−9 to 1 × 10−4 M along with minimal effects of interferences (e.g., Hg2+, Pb2+, and Zn2+) and good reproducibility. The designed aptasensor based on MoS2@Zn-MOF nanofluorophore offers a highly sensitive and selective approach for rapid screening of metal ions in aqueous environments. [ABSTRACT FROM AUTHOR]

Glycated hemoglobin (HbA1c), originating from the non-enzymatic glycosylation of βVal1 residues in hemoglobin (Hb), is an essential biomarker indicating average blood glucose levels over a period of 2 to 3 months without external environmental disturbances, thereby serving as the gold standard in the management of diabetes instead of blood glucose testing. The emergence of HbA1c biosensors presents affordable, readily available options for glycemic monitoring, offering significant benefits to small-scale laboratories and clinics. Utilizing nanomaterials coupled with high-specificity probes as integral components for recognition, labeling, and signal transduction, these sensors demonstrate exceptional sensitivity and selectivity in HbA1c detection. This review mainly focuses on the emerging probes and strategies integral to HbA1c sensor development. We discussed the advantages and limitations of various probes in sensor construction as well as recent advances in diverse sensing strategies for HbA1c measurement and their potential clinical applications, highlighting the critical gaps in current technologies and future needs in this evolving field. [ABSTRACT FROM AUTHOR]

The present investigation examines a novel dual-core photonic crystal fiber (PCF) for early cancer cell detection that is based on a surface plasmon resonance (SPR) biosensor. The PCF is coated with Au/TiO2 layers to boost sensor effectiveness by enhancing the adhesion between the fiber and gold layers. The sensor was simulated and analyzed using the COMSOL Multiphysics software, which is based on the finite element method (FEM). Spectral and amplitude interrogations were used to explore the RI fluctuations of various cancer cells. The observed RI values varied within the range of 1.36–1.401. The biosensor's highest sensitivity was found to be 11,429 nm/RIU for MCF-7 cells using spectral interrogation and 1251.18 RIU−1 for MDA-MB231 cells utilizing amplitude interrogation techniques. Additionally, the sensor shows the maximum resolution for basal cells, which is 8.75 × 10−6 RIU. [ABSTRACT FROM AUTHOR]

Global attention has been increasingly paid to the use of biosensor in water quality monitoring, particularly for on-site determination of biochemical oxygen demand and heavy metal toxicity. However, there have not been many publications that show a practical application of biosensor. In this study, canal water in Ho Chi Minh City was collected to evaluate the potential application of biosensor, which measures respiratory activity of immobilized microorganisms on plastic biochips and calcium alginate beads, for the fast determination of biochemical oxygen demand and heavy metal toxicity. The total amount of aerobic bacteria immobilized on the plastic biochips was 35.6 times higher than that on calcium alginate beads, which, in turn, leads to an increased sensitivity of the biosensor based on the plastic biochips in measurement of biochemical oxygen demand. Additionally, the one-way analysis of variance coupled with Turkey Honestly Significant Difference test at a significant level of 0.05 showed no statistical difference between the values of biochemical oxygen demand in samples at various locations determined by 5-day standard method and biosensor. The biosensor also demonstrated its capability in detection of toxicity of Cu(II), Pb(II), Cr(III), Ni(II), and Cr(VI) at concentrations of 2 mg/L, 0.5 mg/L, 1 mg/L, 0.5 mg/L, and 0.1 mg/L, which are the allowable maximum concentration for industrial wastewater discharged into receiving water, respectively. [ABSTRACT FROM AUTHOR]

Biosensor-based devices are undergoing continuous advances in technology and design. Many studies on biosensor-based tunnel field-effect transistors have recently been published, but none of them has discussed the effect of the dual-drain technique with regard to the sensitivity of nanowire tunnel field-effect transistor-based biosensors. In this work, the role of a dual drain is investigated with respect to both the sensitivity and linearity performance of the device. To cover a vast range of enzymes, the permittivity of the cavities was varied from κ = 3 to κ = 25, and it was observed that a dual drain resulted in 85- and 2000-fold improved sensitivity, respectively. Along with the investigated nanowire, a sensitivity comparison with previous devices was carried out, which showed that for all the devices, the dual-drain technique significantly enhanced sensitivity; hence, in the future, this investigated technique can be used for improved sensing in biomedical devices. [ABSTRACT FROM AUTHOR]

Localized surface plasmon resonance (LSPR) biosensors, which enable nanoscale confinement and manipulation of light, offer the enhanced sensitivity and electromagnetic energy localization. The integration of LSPR with the fiber-optic technology has led to the development of compact and versatile sensors for miniaturization and remote sensing. This comprehensive review explores various sensor configurations, fiber types, and geometric shapes, highlighting their benefits in terms of sensitivity, integration, and performance improvement. Fabrication techniques such as focused non-chemical bonding strategies and self-assembly of nanoparticles are discussed, providing control over nanostructure morphology and enhancing sensor performance. Bio-applications of fiber-optic LSPR (FOLSPR) sensors are detailed, specifically in biomolecular interactions and analysis of proteins, pathogens and cells, nucleic acids (DNA and RNA), and other small molecules (organic compounds and heavy metal ions). Surface modification and detection schemes are emphasized for their potential for label-free and real-time biosensing. The challenges and prospects of FOLSPR sensors are addressed, including the developments in sensitivity, fabrication techniques, and measurement reliability. Integration with emerging technologies such as nanomaterials is highlighted as a promising direction for future research. Overall, this review provides insights into the advancements and potential applications of FOLSPR sensors, paving the way for sensitive and versatile optical biosensing platforms in various fields. [ABSTRACT FROM AUTHOR]

The influence of the geometrical parameters of truncated gold nanocones on the sensitivity of plasmon resonance systems based on them has been studied. The dependence of the bulk refractive index sensitivity on the height, side face inclination angle, and base diameter of the nanocone was studied by the finite-difference time domain method. The parameters corresponding to the highest sensitivity of biosensors based on these particles were identified, and ways to increase it were proposed. [ABSTRACT FROM AUTHOR]

Within the framework of the previously proposed model (S.Yu. Davydov. Phys. Solid State 64, 2018 (2022)), in which the interaction of a macromolecule (MM) with single-layer graphene (SLG) is carried out by stitching of dangling MM bonds with carbon atoms, the effect of these stitching on the mobility of carriers in graphene was studied. It is shown that short-range scattering of MM-SLG stitching prevails over Coulomb scattering. It has also been found that the effect of induced by stitching graphene deformation on mobility can be neglected compared to short-range scattering. The cases of free and epitaxial graphene are considered. The use of the MM-SLG-substrate structure as the basis of a biosensor is discussed. [ABSTRACT FROM AUTHOR]

Herein, a self-powered lactate biosensor (SPLBs) was assembled to detect lactate in sweat based on flexible textile matrix enzymatic electrodes. A porous three-dimensional electrode with high flexibility and electrical conductivity was obtained by decorating composites of reduced graphene oxide and carboxylate multiwalled carbon nanotubes onto a cellulose fabric substrate. The excellent enzyme embedding method using a gel electrolyte showed a Michaelis–Menten constant of 1.46 mM, indicating the high enzymatic activity of lactate dehydrogenase. Moreover, the assembled (SPLBs) displayed a sensitivity of 3.16 µW mM−1 cm−2 with a linear range of 0–10 mM and a detection limit of 9.49 µM. Additionally, the biosensor has good tensile flexural stability, selectivity, and long-term stability. When integrated into clothing, the (SPLBs) recovered 91.5–102.3% of lactate from real sweat, with a relative standard deviation of less than 4.16%. This biosensor is promising for sensing lactate in human sweat. [ABSTRACT FROM AUTHOR]

One significant constraint in the advancement of biosensors is the signal-to-noise ratio, which is adversely affected by the presence of interfering factors such as blood in the sample matrix. In the present investigation, a specific aptamer binding was chosen for its affinity, while exhibiting no binding affinity towards non-target bacterial cells. This selective binding property was leveraged to facilitate the production of magnetic microparticles decorated with aptamers. A novel assay was developed to effectively isolate S. pneumoniae from PBS or directly from blood samples using an aptamer with an affinity constant of 72.8 nM. The capture experiments demonstrated efficiencies up to 87% and 66% are achievable for isolating spiked S. pneumoniae in 1 mL PBS and blood samples, respectively. [ABSTRACT FROM AUTHOR]

This manuscript presents the development and analysis of a highly sensitive surface plasmonic biosensor tailored for forensic applications, with a specific focus on the precise identification of illegal drugs. The sensor employs a synergistic combination of graphene, glass(fused silica), and gold as fundamental building materials, harnessing their unique properties to enhance detection capabilities. By integrating glass as the substrate, the sensor benefits from its excellent transparency, mechanical stability, and chemical inertness. This provides a solid foundation for the graphene layer, allowing for precise and reliable sensing interactions. A comparative evaluation with existing technologies highlights the sensor's competitive edge in terms of both sensitivity and accuracy. The application of glass as the substrate plays a pivotal role in providing a robust platform for the graphene layer, thereby contributing significantly to the sensor's overall performance and applicability in forensic scenarios. The proposed sensor demonstrates remarkable sensitivity, achieving a maximum relative sensitivity of 4889 GHz/RIU enabling the detection of even the slightest shifts in refractive index—a crucial aspect in the identification of illicit drugs. The sensor's wide range of FOM values, ranging from 15.138 to 54.932 RIU−1, further highlights its adaptability across a diverse spectrum of refractive index measurements. [ABSTRACT FROM AUTHOR]

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