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One-dimensional plasmonic nanogratings (1D-PNGs) with high aspect ratios and narrow grooves promise enhanced coupling for hybrid graphene systems with the localized surface plasmon of the metallic grating and graphene surface plasmons. However, both the fabrication of the 1D-PNG and the application of graphene to it are difficult. We developed 1D-PNGs with a high aspect ratio of 15 and narrow grooves of 100 nm in width using the tapered mold method and a dry graphene-transfer procedure. Raman spectroscopy measurements showed that monolayer graphene was successfully transferred onto the 1D-PNGs, and the graphene was strongly doped with Au in the 1D-PNGs. Graphene on narrow grooves (free-standing graphene) demonstrated an almost identical p-doping level to graphene on Au because the narrow groove width allowed sufficient doping by Au for graphene on grooves. Reflectance measurements showed that the 1D-PNGs exhibited polarization- and wavelength-selective absorption at infrared (IR) wavelengths, and the effect of graphene blue-shifted the absorption peak wavelength induced by the surface plasmon resonance of 1D-PNGs. Numerical calculations agree well with these experimental results and indicate that the electric field strongly localizes on graphene in the grooves. Moreover, the doping level tunes the absorption wavelength owing to the coupling with graphene plasmons and the surface plasmon resonance of 1D-PNGs. This could provide electrical tunability to the graphene plasmons. Our fabrication procedure produced hybrid graphene-1D-PNGs with high aspect ratios and narrow groove systems for IR wavelengths. This system can contribute to developing high-performance electrically tunable graphene-based IR photodetectors, tunable IR emitters/absorbers, and biological sensors. [ABSTRACT FROM AUTHOR]

Theoretical models have predicted that pH-responsive surface groups can reduce the sensitivity of field-effect transistor biosensors. However, attempts to prove this experimentally have shown conflicting results. In this work, a graphene field effect transistor (gFET) biosensor is used, which, without modification, is pH insensitive. The surface of the graphene is then functionalized using 1-hydroxypyrene to modulate the pH sensitivity of the gFET. A pH sensitivity ranging from 3.9 to 36.8 mV/pH was demonstrated. The biosensitivity of the gFETs was tested using streptavidin–biotin as a model system. The experimental results showed no correlation between biosensitivity and pH sensitivity. An electrochemical membrane model was used to determine the expected relationship between biosensitivity and pH sensitivity. The model results show that biosensitivity does not decrease until a certain threshold pH sensitivity is reached. This threshold is dependent on factors such as the acid dissociation constants of the surface hydroxyl groups and ion concentration. Furthermore, the differences between the simulation and experiment suggest that the effect of screening is greatly reduced when the analyte binds within a membrane. [ABSTRACT FROM AUTHOR]

Early cancer diagnosis strongly relies on finding appropriate materials for the detection of respected biomarkers. For the first time, we have theoretically investigated the capability of the MoSe2 monolayer to detect three lung cancer biomarkers, including hexanal, nonanal, and p-cresol. To this end, adsorption performance, bandgap alteration, and charge transfer of the MoSe2 monolayer upon exposure to the three biomarkers were studied using density functional theory. The results, in all cases, indicate that the charge transfer is from the monolayer to the adsorbed biomarkers, and the adsorption of biomarkers decreases the bandgap of the monolayer, approving the p-type sensing character of the MoSe2 monolayer. This is in complete agreement with the band structure analysis of the material and the previous reports in the literature. Our findings demonstrated the appropriate performance of the MoSe2 monolayer in terms of the physisorption of the lung cancer biomarkers and desirable recovery times in the desorption process. Further performance enhancement of MoSe2 as a lung cancer biosensor can be the subject of future studies. [ABSTRACT FROM AUTHOR]

Detecting multiple targets in complex cellular and biological environments yields more reliable results than single-label assays. Here, we introduced an electrochemical biosensor equipped with computing functions, acting as a smart automaton to enable computing-based detection. By defining the logic combinations of miR-21 and miR-122 as detection patterns, we proposed the corresponding AND and OR detection automata. In both logic gate modes, miR-21 and miR-122 could be replaced with single-stranded FO or FA, modified with Fc, binding to the S chain on the electrode surface. This process led to a significant decrease in the square wave voltammetry (SWV) of Fc on the same sensing platform, as numerous ferrocene (Fc)-tagged DNA fragments escaped from the electrode surface. Experimental results indicated that both automata efficiently and sensitively detected the presence of the two targets. This strategy highlighted how a small amount of target could generate a large current signal decrease in the logic automata, significantly reducing the detection limit for monitoring low-abundance targets. Moreover, the short-stranded DNA components of the detection automata exhibited a simple composition and easy programmability of probe sequences, offering an innovative detection mode. This simplified the complex process of detection, data collection, computation, and evaluation. The direct detection result ("0" or "1") was exported according to the embedded computation code. This approach could be expanded into a detection system for identifying other sets of biomarkers, enhancing its potential for clinical applications. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms of assembly and disassembly of macromolecular structures in cells relies on solving biomolecular interactions. However, those interactions often remain unclear because tools to track molecular dynamics are not sufficiently resolved in time or space. In this study, we present a straightforward method for resolving inter‐ and intra‐molecular interactions in cell adhesive machinery, using quantum dot (QD) based Förster resonance energy transfer (FRET) nanosensors. Using a mechanosensitive protein, talin, one of the major components of focal adhesions, we are investigating the mechanosensing ability of proteins to sense and respond to mechanical stimuli. First, we quantified the distances separating talin and a giant unilamellar vesicle membrane for three talin variants. These variants differ in molecular length. Second, we investigated the mechanosensing capabilities of talin, i.e., its conformational changes due to mechanical stretching initiated by cytoskeleton contraction. Our results suggest that in early focal adhesion, talin undergoes stretching, corresponding to a decrease in the talin‐membrane distance of 2.5 nm. We demonstrate that QD‐FRET nanosensors can be applied for the sensitive quantification of mechanosensing with a sub‐nanometer accuracy. [ABSTRACT FROM AUTHOR]

The development of efficient nonenzymatic catalysts for the electro-oxidation of glucose is vital for glucose biosensors. Herein, we report the preparation of a branch-structured catalyst comprising an amorphous/crystalline heterophase made from AuCu alloy shells and Cu2O cores (Cu2O@a/c-AuCu). The Cu2O@a/c-AuCu catalyst exhibits a good electrocatalytic activity for the electro-oxidation of glucose. The Cu2O@a/c-AuCu-based glucose biosensor shows a high sensitivity (345 μA mM−1 cm−2) and a wide concentration detection range (0.1–10 mM). The glucose detection accuracy of the Cu2O@a/c-AuCu sensor in animal serum was consistent with that of the commercial glucometer. The outcomes of this work offer insights for constructing alloy-based heterophase nanocatalysts for biosensing and biological applications. [ABSTRACT FROM AUTHOR]

Hydrophilicity‐hydrophobicity modulation of active sites provides a promising strategy for enhancing catalytic performance. Current researches focus on the influence of substrate molecules, however, the role of H2O molecules is often overlooked in nanozyme‐catalyzed reactions. Herein, bioinspired Pt@ZIF‐R (R = ‐90, ‐8, ‐8@TMS, where TMS is tetraethoxysilane) nanozymes are designed as model catalysts, with Pt nanoparticles as active centers and metal organic‐framework nanocavities as hydrophilic‐hydrophobic binding pockets, revealing the critical role of H2O in the peroxidase‐like catalytic process of H2O2 decomposition. A positive correlation between catalytic activity and hydrophobicity is observed, and strong hydrophobic Pt@ZIF‐8@TMS nanozyme exhibits the best catalytic performance. Theoretical calculations indicate that as hydrophobicity increases, solvent H2O reduces the competitive adsorption with H2O2 and decreases the energy barrier of the rate‐determining step (2*O→*O2) simultaneously. In addition, the desorption of the product H2O is thermodynamically favorable with increasing hydrophobicity. Importantly, Pt@ZIF‐8@TMS nanozyme is successfully used to develop a colorimetric biosensor for the detection of organophosphorus pesticides, with a detection limit as low as 0.7 ng mL−1, which is superior to numerous existing methods. This work provides fundamental insights into the function of hydrophobicity in boosting catalytic activity, which may offer guidance for the development of efficient nanozymes. [ABSTRACT FROM AUTHOR]

Bioelectronic implantable devices are adept at facilitating continuous monitoring of health and enabling the early detection of diseases, offering insights into the physiological conditions of various bodily organs. Furthermore, these advanced systems have therapeutic capabilities in neuromodulation, demonstrating their efficacy in addressing diverse medical conditions through the precise delivery of stimuli directly to specific targets. This comprehensive review explores developments and applications of bioelectronic devices within the biomedical field. Special emphasis is placed on the evolution of closed‐loop systems, which stand out for their dynamic treatment adjustments based on real‐time physiological feedback. The integration of Artificial Intelligence (AI) and edge computing technologies is discussed, which significantly bolster the diagnostic and therapeutic functions of these devices. By addressing elemental analyses, current challenges, and future directions in implantable devices, the review aims to guide the pathway for advances in bioelectronic devices. [ABSTRACT FROM AUTHOR]

Bioactive NAD+ mediated multiple biocatalytic pathways in metabolic networks. Refining the structure of NADH oxidase-like (NOX) mimics to efficiently replenish NAD+ has been promising but challenging in NAD+-dependent dehydrogenase electrochemical cascade biosensing. Herein, we discovered that PtOx structures, formed via lattice oxygen translocation from WO3 to Pt NPs at the interface, potentially activate and modulate the NOX-like functionality in Pt@WO3 nanosheets. Incorporating PtOx leads to a more positive valence of Pt species within Pt/PtOx@WO3−x, where the PtO2 species serve as preeminent reaction sites for NADH coordination, activation, and dehydrogenation. Consequently, such nanozymes display enhanced NOX-like activity towards NADH oxidation in comparison to Pt@WO3. Ultimately, the 650-Pt/PtOx@WO3−x nanozyme is employed in an electrochemical cascade biosensor for β-hydroxybutyrate (HB) detection, achieving a calculated detection limit of 25 μM. This study offers insights into PtOx activation in Pt-based NOX mimics and supports the future development of NAD+/NADH-dependent electrochemical biosensors. [ABSTRACT FROM AUTHOR]

Single‐atom nanozyme materials have demonstrated exceptional specific catalytic activity due to the atomic‐level dispersion of their active centers. However, the exploration of catalytic mechanisms for single‐atom catalysts is so far limited to the 2D surfaces of nanozymes. In this study, porous single‐atom Fe nanozyme (psaFeN) is successfully prepared through a straightforward coordination‐assisted polymerization‐assembly strategy. The psaFeN composite nanospheres are uniformly sized, exhibiting excellent dispersibility with well‐organized pore channels extending from the center to the surface. Density functional theory calculations reveal that in the psaFeN nanozyme, the (010) facets serve as the primary active surface, where Fe atoms form tri‐coordinated or tetra‐coordinated structures with doped nitrogen atoms. The (100) facets act as auxiliary reactive surfaces with tetra‐coordinated Fe─N as the active center. psaFeN exhibits excellent POD‐like activity (Km = 1.77 mM; Vmax = 173.53 × 10−⁸ M s−1). Given this exceptional bioactivity, a portable colorimetric biosensor is constructed for distinguishing artificially ripened fruits from naturally ripened ones. The sensor achieves precise discrimination with a detection limit as low as 310 nmol L−1. This study is anticipated to offer valuable insights into understanding the 3D catalytic mechanisms of single‐atom nanozymes, promoting their application in the development of robust biosensors for food safety. [ABSTRACT FROM AUTHOR]

By coating the electrodes of a cochlear implant (CI) electrode array with a powdered form of molecularly imprinted polymer (MIP), a straightforward process to functionalize existing electrodes to selectively detect histamine is demonstrated. Detection is based on non‐Faradaic impedance spectroscopy, omitting the need for a reference electrode or redox mediators, and fitting to a 5‐element equivalent electronic circuit. Proof‐of‐concept measurements on three functionalized cochlear implants in three human cadaveric cochleae indicate a level of detection of 200 nM of histamine in albumin‐based artificial perilymph following a sigmoid dose‐response trend up to 10 mM. This sensitivity enables quantized and localized analysis of histamine‐mediated inflammation immediately following the CI operation. The selectivity and adaptability of MIPs opens possibilities to detect a wide spectrum of inflammation markers inside the human cochlea and could be used for fast mid‐ or postoperative intervention to improve the medical implant's outcome. [ABSTRACT FROM AUTHOR]

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]

Summary: Gelatine is obtained from the hydrolysis of collagen in bones, skin, fins, fish scales and insect bodies of cattle, pigs, camels, poultry, fish and insects. Consequently, the diversity and availability of gelatine sources, along with gelatine authentication, are concerns for those consuming gelatine products from religious, health and economic perspectives. Therefore, rapid and reliable protein‐ or DNA‐based detection methods have been developed for gelatine authentication. This review discusses and evaluates biosensor methods, comparing them with various analytical methods in terms of their popularity and precision. Additionally, the development of biosensor methods has been explored to identify a reference for a rapid, accurate, portable and simple method for gelatine detection with a low detection limit and high specificity. [ABSTRACT FROM AUTHOR]

In this study, we developed a sensitive method for monitoring α‐amylase using a fluorogenic approach based on the host‐guest complexation between an amphiphilic pyrenyl derivative (1) and γ‐cyclodextrins (γ‐CDs). The compound 1 self‐assembles into nanofibrils in aqueous solutions. Upon the introduction of γ‐CD, compound 1 forms an inclusion complex with it. This complex then participates in the formation of a 2 : 2 complex with another complex, leading to strong excimer fluorescence. Upon interaction with α‐amylase, γ‐CD undergoes hydrolysis, leading to the regeneration of nanofibrils, which is accompanied by a decrease in excimer fluorescence and an increase in monomeric fluorescence. This ratiometric fluorescence color change enables the sensitive detection of low levels of α‐amylase in human urine, offering a practical approach for early screening of pancreatic‐related diseases. [ABSTRACT FROM AUTHOR]

The rapid advancement in personalized healthcare has driven the development of wearable biomedical devices for real-time biomarker monitoring and diagnosis. Traditional invasive blood-based diagnostics are painful and limited to sporadic health snapshots. To address these limitations, microneedle-based sensing platforms have emerged, utilizing interstitial fluid (ISF) as an alternative biofluid for continuous health monitoring in a minimally invasive and painless manner. This review aims to provide a comprehensive overview of microneedle sensor technology, covering microneedle design, fabrication methods, and sensing strategy. Additionally, it explores the integration of monitoring electronics for continuous on-body monitoring. Representative applications of microneedle sensing platforms for both monitoring and therapeutic purposes are introduced, highlighting their potential to revolutionize personalized healthcare. Finally, the review discusses the remaining challenges and future prospects of microneedle technology. Highlights: • Microneedle sensors enable minimally invasive and continuous biomarker monitoring through dermal interstitial fluid. • This review offers a comprehensive overview of microneedle sensing technology. • Key topics covered include skin physiology, microneedle design, sensing mechanisms, monitoring electronics, and applications. [ABSTRACT FROM AUTHOR]

New technologies can help to achieve the sustainable development goals (SDGs) of the United Nations. We discuss the contribution of microfluidic electrochemical biosensors to advancing the SDGs. These sensors can be applied in various fields given their low cost, self-powering ability, environmental compatibility, ease of use, and small sample volume requirements. [ABSTRACT FROM AUTHOR]

Ten strains of the yeast Yarrowia lipolytica were constructed, the genomes of which contain the hrGFP gene under regulation of the formate dehydrogenase promoters. The resulting strains can act as whole-cell biosensors for the detection of formate ions in various media. By visual assessment of the biomass fluorescence, we selected the three most promising yeast strains. The main biosensor characteristics (threshold sensitivity, amplitude, and response time) of the selected strains were measured. As a result, in terms of characteristics, the B26 strain was recognized as the most suitable for the detection of formate ions. A carbon source for the nutrient medium that does not reduce the activation of the biosensor was selected. Furthermore, we showed that unlike formate and formaldehyde, methanol practically does not induce the biosensor fluorescence response. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. This article summarizes the applications of biosensors and biomimetic sensors in the detection of residues in dairy products. Biosensors use biological molecules, such as enzymes or antibodies, to detect residual substances in dairy products, demonstrating high specificity and sensitivity. Biomimetic sensors, inspired by biosensors, use synthetic materials to mimic biological sensing mechanisms, enhancing stability and reproducibility. Both sensor types have achieved notable success in detecting pesticide residues, veterinary drugs, bacteria, and other contaminants in dairy products. The applications of biological and biomimetic sensors not only improve the efficiency of residue detection in dairy products but also have the potential to reduce the time and cost of traditional methods. Their specificity and high sensitivity make them powerful tools in the dairy industry, thus contributing to ensuring the quality and safety of dairy products and meeting the growing consumer demands for health and food safety. [ABSTRACT FROM AUTHOR]

Optical fibers are used in the communications, biological sensors and chemical sensors. We investigate a variable-coefficient modified Hirota equation for the amplification or absorption of pulses propagating in an inhomogeneous optical fiber. With respect to the complex envelope of the optical field, we construct the infinitely-many conservation laws based on the existing Lax pair. According to the existing Darboux transformation, we derive the three-soliton solutions, the higher-order breather solutions and breather-to-soliton transition condition. Amplitudes of the two solitons change after the interaction, while velocities of them are unchanged via asymptotic analysis. When $ P(z)=0 $ P (z) = 0 , interactions among the three parabolic or wavy solitons, interaction between the two parabolic or wavy or crooked breathers, and interactions among the three parabolic and wavy breathers are presented, where $ P(z) $ P (z) is related to the nonlinear focus length. Velocities of three solitons or two crooked breathers with $ P(z)\neq 0 $ P (z) ≠ 0 are different from those with $ P(z)=0 $ P (z) = 0. Based on the breather-to-soliton transition condition, when $ P(z)=0 $ P (z) = 0 , parabolic or wavy multi-peak and M-shaped solitons are presented; when $ P(z)\neq 0 $ P (z) ≠ 0 , the crooked periodic wave and anti-dark soliton are shown. [ABSTRACT FROM AUTHOR]

[Display omitted] • A newly developed method based on carbon dots fluorescence is described in details; • The newly developed method allows distinguish among isomeric peptides; • Early-stage aggregation states can be investigated by the newly designed method; • Tailoring the surface design of carbon dots is fundamental for the success of the method. Carbon dots (CD) are widely investigated particles with interesting fluorescent properties which are reported to be used for various purposes, as they are biocompatible, resistant to photobleaching and with tuneable properties depending on the specific CD surface chemistry. In this work, we report on the possibility to use opportunely designed CD to distinguish among isobaric peptides almost undistinguishable by mass spectrometry, as well as to monitor protein aggregation phenomena. Particularly, cell-penetrating peptides containing the carnosine moiety at different positions in the peptide chain produce sequence specific fluorescent signals. Analogously, different insulin oligomerization states can also be distinguished by the newly proposed experimental approach. The latter is here described in details and can be potentially applied to any kind of peptide or protein. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Interfacing DNA oligonucleotides and DNA aptamers with gold nanoparticles has generated numerous functional hybrid materials for sensing, self‐assembly and drug delivery applications. Our lab has been working in this area for 15 years. In this article, the current understanding of the adsorption of DNA to gold nanoparticles is summarized, and related applications in bioconjugation of DNA to gold surface is described. In addition, problems of using gold nanoparticles to signaling aptamer binding are discussed. Finally, re‐selection of aptamers for previously reported targets using the library‐immobilization method is reviewed. What is the most favorite and original chemistry developed in your research group? My most favorite and original work is the study of biointerface chemistry between DNA oligonucleotides and gold nanoparticles enabling rapid DNA bioconjugation by lowering the pH and freezing. How do you get into this specific field? Could you please share some experiences with our readers? My PhD training was focused on catalytic DNA for the detection of metal ions, when I used gold nanoparticles to signal the reactions catalyzed by DNA. When I started my independent career in the University of Waterloo in 2009, I realized that there were many fundamental issues regarding gold nanoparticles and DNA to be studied. My first teaching assignment was a course named 'Surfaces and Interfaces'. By teaching this course, I learned a lot of surface science concepts that were later used in my research. That was the starting point for me to set up my own research program in this area. What is the most important personality for scientific research? Curiosity, careful observation, critical thinking, and keep trying. How do you keep balance between research and family? Research and personal life don't have to be always in conflict. New ideas may spark when I am in a relaxed family environment. What are your favorite journals? Journal of the American Chemical Society, Angewandte Chemie International Edition, Nucleic Acids Research, Analytical Chemistry, Langmuir. What are your hobbies? Running; traveling; watching movies. [ABSTRACT FROM AUTHOR]

Cancer-derived exosomes, a subset of extracellular vesicles, carry vital information about tumor progression, metastasis, and drug resistance, making them attractive targets for cancer diagnostics and therapeutics. The identification of these cancer exosomes with high sensitivity and specificity has enormous promise for early diagnosis and prognosis. Nano-mediated biological sensors are establishing themselves as innovative techniques for detecting cancer exosomes based on the distinctive physicochemical attributes of nanomaterials to improve detection sensitivity and specificity. This article presents an overview of the recent developments in nano-mediated biosensors directed particularly toward the detection of cancer exosomes. The development of ultrasensitive sensors has been enhanced by using nanomaterials such as magnetic nanoparticles, quantum dots, and gold nanoparticles. Surface modifications of these nanomaterials by conjugating the cancer-specific antibodies or aptamers facilitate target recognition and binding of cancer exosomes, thus increasing the sensitivity of detection. This review compiles different detection techniques, including SERS, Electrochemical, SPR, Chemiluminescence, and Fluorescence-based biosensor detection, in combination with different nanomaterials that are currently being researched or utilized as biosensors. [ABSTRACT FROM AUTHOR]

Bowel sound (BS), a measure of bowel activity, can be observed through listening. By utilizing BS, many studies have been conducted for the early, harmless and practical detection of intestinal diseases. Basically, single (SB) and multiple (MB) burst-like bowel sounds, although observable with simple microphones, may not be accurately detected due to their abrupt character, long quiet periods (QP), and may be confused with other sounds such as stomach, muscle, breath. In this study, after the preprocessing steps, a distribution matrix (P) was formed by bringing together the characteristic time-frequency features specific to bowel sounds, and new reflection space (Q) stretching the indifference subspace was obtained from the eigenvectors corresponding to zero or near zero eigenvalues of this matrix. In order to determine which class a record belongs to; it will be sufficient to look at the common vector of which class its projection to the new space converges with the co-change matrix. In experimental studies, the average rates of SB, MB, QP, and non-BS classes in one-minute recordings were 2.3%, 0.3%, 92.9%, and 4.5%, respectively, while in tests performed with one-minute recordings that were never used in training, 87.5% of single bursts (SB), 35.7% of multiple bursts (MB), 84.3% of non-BS parts were assigned to the correct classes. As a result, by using this new reflection space (Q), which brings the in-class samples closer to each other and distances the interclass samples from each other by looking at the distributions of all classes, bowel sounds can be largely separated from other sounds, regardless of the training set, without consulting medical professionals. [ABSTRACT FROM AUTHOR]

In the bloodstream or other physiological fluids, "circulating cells and sub-cellular bio-particles" include many microscopic biological elements such as circulating tumor cells (CTCs), cell-free DNA (cfDNA), exosomes, microRNAs, platelets, immune cells, and proteins are the most well-known and investigated. These structures are crucial biomarkers in healthcare and medical research for the early detection of cancer and other disorders, enabling treatment to commence before the onset of clinical symptoms and enhancing the efficacy of treatments. As the size of these biomarkers to be detected decreases and their numbers in body fluids diminishes, the detection materials, ranging from visual inspection to advanced microscopy techniques, begin to become smaller, more sensitive, faster, and more effective, thanks to developing nanotechnology. This review first defines the circulating cells and subcellular bio-particles with their biological, physical, and mechanical properties and second focuses on their diagnostic importance, including their most recent applications as biomarkers, the biosensors that are utilized to detect them, the present obstacles that must be surmounted, and prospective developments in the domain. As technology advances and biomolecular pathways are deepens, diagnostic tests will become more sensitive, specific, and thorough. Finally, integrating recent advances in the diagnostic use of circulating cells and bioparticles into clinical practice is promising for precision medicine and patient outcomes. [Display omitted] [ABSTRACT FROM AUTHOR]

Since influenza and COVID-19 cause similar symptoms, the need for selective, sensitive and practical systems for influenza A detection has been highlighted. For this reason, in this work, a graphene (Gr) based nanomaterial modified anti-hemagglutinine 3, from now on will be called Gr-antiH3, based disposible electrochemical influenza immunosensor was developed. In order to obtain the highest sensitivity, the effects of various Gr-based nanomaterials on developed electrochemical immunosensor responses were investigated. For this purpose, graphene oxide, Gr, Gr-platinum (Gr-Pt), Gr-gold and Gr-gold-platinum nanomaterials were synthesized and characterized via electrochemical impedance spectroscopy (EIS). As a result, since the best results were obtained with Gr-Pt, this nanomaterial was integrated into H3N2 immunosensor system as a modifier. The Gr-Pt modified immunosensor was shown to provide a linear range from 0.5 µg/mL to 7 µg/mL. The limit of detection was 0.38 µg/mL and limit of quantification was 1.28 µg/mL with a relative standard deviation of 3.05%. The developed biosensor was applied to H3N2 detection in synthetic saliva samples and promising results were obtained with recoveries of 100.41 ± 1.10%. [ABSTRACT FROM AUTHOR]

In the graphical abstract, we illustrate the innovative design of physical–chemical hybrid crosslinked composite hydrogels that exhibit a unique combination of properties, making them well-suited for advanced applications in flexible electronics and biosensing. These hydrogels demonstrate ideal stretchability and compressibility, alongside excellent adhesion capabilities. Their design is strategically tailored to ensure biocompatibility without compromising the sensitive detection of physiological signals. The graphical representation showcases the multifaceted nature of these materials, highlighting their dynamic responsiveness to mechanical stimuli and their potential to seamlessly interface with biological tissues for real-time monitoring and diagnostic purposes. [Display omitted] With the advancement of wearable and implantable medical devices, hydrogel flexible bioelectronic devices have attracted significant interest due to exhibiting tissue-like mechanical compliance, biocompatibility, and low electrical resistance. In this study, the development and comprehensive performance evaluation of poly(acrylic acid)/ N,N′-bis(acryloyl) cystamine/ 1-butyl-3-ethenylimidazol-1-ium:bromide (PAA/NB/IL) hydrogels designed for flexible sensor applications are introduced. Engineered through a combination of physical and chemical cross-linking strategies, these hydrogels exhibit strong mechanical properties, high biocompatibility, and effective sensing capabilities. At 95 % strain, the compressive modulus of PAA/NB/IL 100 reach up to 3.66 MPa, with the loading–unloading process showing no significant hysteresis loop, indicating strong mechanical stability and elasticity. An increase in the IL content was observed to enlarge the porosity of the hydrogels, thereby influencing their swelling behavior and sensing functionality. Biocompatibility assessments revealed that the hemolysis rate was below 5 %, ensuring their suitability for biomedical applications. Upon implantation in rats, a minimal acute inflammatory response was observed, comparable to that of the biocompatibility control poly(ethylene glycol) diacrylate (PEGDA). These results suggest that PAA/NB/IL hydrogels hold promise as biomaterials for biosensors, offering a balance of mechanical integrity, physiological compatibility, and sensing sensitivity, thereby facilitating advanced healthcare monitoring solutions. [ABSTRACT FROM AUTHOR]

Sweat glucose serves as a significant biomarker of health, necessitating accurate determination at the micromolar level for noninvasive monitoring. To address this need, we design an organic field‐effect transistor (OFET)‐based enzymatic sensor to quantify glucose levels in human sweat. The extended‐gate structure of the OFET device ensures stable analyte detection in human sweat owing to its isolated configuration. The extended‐gate‐type OFET has been functionalized with glucose oxidase and an N‐ethylphenazonium‐based mediator‐attached monolayer. This configuration facilitates electron relay, enabling accurate and reproducible glucose detection. Leveraging the amplification ability of the OFET, the enzymatic sensor exhibited highly sensitive glucose detection, achieving a low limit of detection (2.9 μM) suitable for sweat analysis requirements. In addition, the sensor exhibited high discriminability in detecting glucose amidst interferents commonly found in sweat, indicating its practical feasibility for sweat analysis. Validation of glucose recovery rates (95–105 %) in human sweat, without pretreatment, was performed using established instrumental analysis methods. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are tiny plastic particles ranging from 1 to 5000 μm in size and are of particular concern nowadays because of their ecological risk & health concerns. MPs are prevalent environmental contaminants and have been reported in various ecosystems such as soil, air, water, and road dust. However, a thorough understanding of their distribution across various environmental matrices remains elusive. Therefore, this review aims to fill this knowledge gap by examining the abundance of MPs and different techniques utilized for their identification and characterization including sampling, extraction, identification, characterization, and quantification methods. MPs possess a large surface area and exhibit hydrophobic properties, providing a substrate for environmental pollutants such as Polyaromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs). The primary mechanisms through which pollutants attached to MPs are hydrophobic interactions, electrostatic attraction, hydrogen bonding, halogen bonding, and π-π interactions. Therefore, a better understanding of these interactions is crucial for determining the fate and transport of MPs and co-contaminants in the environment. Researchers commonly deploy techniques such as stereomicroscopy and spectroscopy for the characterization and quantification of MPs. However, size and chemical properties of MPs pose a challenge in their quantification, thereby necessitating the development of standardized analytical methods. Use of bio-indicators for MPs biomonitoring has gained popularity in recent years as an affordable option over conventional techniques however research in this area is limited. With this intention, the present review is designed to provide information about the status of the field and advance our knowledge of MPs in various environmental matrices. Highlights: • Soil and road dust are one of the major sources of MPs for aquatic ecosystem. • Fibers of polypropylene & polyethylene are the most abundant MPs in soil & aquatic systems and show pollutant adsorption. • Biomonitoring of MPs emerges as a new alternative for their quantification. [ABSTRACT FROM AUTHOR]

Random lasers operate without a traditional resonator cavity compared with traditional lasers, instead relying on multiple scattering events within a disordered medium to amplify light. Their emission spectrum and spatial characteristics are determined by the disorder within the medium rather than by specific resonant modes. ZnO nanostructures are ideal for random lasers due to their strong light emission properties and high refractive index, facilitating efficient light scattering and amplification within the disordered medium. Additionally, their wide bandgap and ability to support both optical and electrical pumping make them versatile for various laser applications. ZnO-based random lasers unlock a future beyond high-resolution displays and foldable phones due to their speckle-free emission and a knack for scattering. In medicine, they promise label-free cellular insights, targeted cancer treatments, and miniaturized diagnostics. However, the future of ZnO-based random lasers demands careful crafting. Scalability, cost, and longevity remain hurdles. This review first addresses the synthesis parameters controlling ZnO nanostructures as gain media in random lasers. Then, recent advances in random laser design and performance are discussed, followed by an explanation of the pumping mechanisms. The review concludes by addressing the potential applications of ZnO-based random lasers, including sensors, imaging, medical and display technologies. [ABSTRACT FROM AUTHOR]

We have developed a bienzymatic biosensor that contains acetylcholinesterase together with butyrylcholinesterase co-immobilized on the same electrode modified with a stabilized copper containing Prussian blue electrodeposited on electrodes coated with 4-aminothiophenol monolayer using diazonium chemistry and copper nanoparticles for improved sensitivity. There are organophosphorus and carbamate neurotoxic insecticides that inhibit only one of the two enzymes, e.g., pirimicarb inhibits butyrylcholinesterase at much lower concentrations than acetylcholinesterase while methomyl inhibits only acetylcholinesterase. Our system is simple and in a single measurement provides a sensitive signal for insecticides' presence based on the inhibition of the enzyme with the highest affinity for each toxic compound. The limits of detection are 50 ng/mL pirimicarb for the bienzymatic biosensor in comparison with 400 ng/mL pirimicarb for the acetylcholinesterase biosensor and 6 ng/mL methomyl for the bienzymatic biosensor, while inhibition is obtained for the butyrylcholinesterase biosensor at 700 ng/mL. [ABSTRACT FROM AUTHOR]

Accurate and rapid quantification of cytokines in biofluids is crucial for early disease diagnosis, management, and prevention. However, it still remains challenging for existing sensors due to the broad dynamic range of cytokines and high interference from sample matrices. To overcome these challenges, electrochemical (EC) and field‐effect transistor (FET) dual‐mode biosensing is integrated on an extended‐gate carbon nanotube field‐effect transistor. This biosensor chip effectively eliminates direct contact between the device and the solution and employs independent signal readouts based on two distinct response mechanisms, thereby circumventing the limitations associated with conventional transistor biosensors. Selective detection of cytokine (e.g., Interferon‐γ, IFN‐γ) is achieved by the FET sensing mode (0.1 to 4000 pg mL−1, with a limit of detection of 24.1 fg mL−1) and the EC sensing mode (0.4–2000 ng mL−1) at different concentration range. The feasibility of real sample analysis using the EC‐FET dual‐mode biosensor is confirmed by detecting salivary levels of IFN‐γ. The combination of EC and FET sensing modes not only provides high sensitivity and a wide response range (seven orders of magnitude) to accommodate various biological samples but also improves the reliability of detection results, which shows promising applications in biological analysis and early disease diagnosis. [ABSTRACT FROM AUTHOR]

As widely used commercial sensors, amperometric biosensors based on electrochemical (EC) reactions exhibit good linearity and reproducibility but suffer from a low dynamic range and poor limit of detection (LoD). In contrast, biosensors utilizing field‐effect transistors (FETs) demonstrate a wide detection range and ultralow LoDs but are susceptible to interferences or ionic strength influences and have poor quantitative accuracy due to their nonlinear response mechanism. Here, EC and carbon nanotube (CNT) FET‐based biosensors are integrated into one chip via a compatible fabrication process. The dual‐mode biosensing chip (DMSC) provides the advantages from both the EC biosensors and FET biosensors; these advantages include high reliability and accuracy for quantitatively detecting glucose, a dynamic detection range spanning 6 orders of magnitude, and a detection limit of 1 fM. The introduction of a time‐division multiplexing detection method enables the DMSC to carry out complementary detection of the same target, providing early warning of specific abnormal biomarkers and accurate determination of their concentration in real time. The DMSC approach is generally applicable to the detection of other biomarkers and provides exciting opportunities for more accurate self‐monitoring diagnostics in real situations. [ABSTRACT FROM AUTHOR]

Electrochemical (EC) analysis has emerged as a high‐sensitivity, reliable, cost‐effective, and rapidly evolving technique that has garnered significant attention across diverse domains. Furthermore, EC‐based techniques hold great potential for miniaturization and integration. The integration of EC techniques with diverse mode/signal (such as light, magnetic, and thermal signals, etc.) provides unique opportunities for biosensors to acquire more information through a single sensing platform. By coupling multiple signals or processing them logically, the detection accuracy can be further improved, and the probability of false positives or negatives can be minimized. In this review, a thorough analysis of multi‐ mode/signal sensors in the field of EC sensing is conducted, along with their integration with various sensing techniques (e.g., fluorescence, photothermal, colorimetry, microfluidic, etc.). The aim is to delve into the latest advances, potential applications, as well as challenges in multi‐mode/signal biosensors, where the utilization of multiple sensing modalities helps enhance accuracy, sensitivity, and selectivity. This review provides new insight into the synergistic effects of integrating EC sensing with other techniques, aiming to shed light on the near‐future developments in EC‐integrated multi‐mode/signal biosensors. [ABSTRACT FROM AUTHOR]

Photonic crystals are a new class of optical microstructure materials characterized by a dielectric constant that varies periodically with space and features a photonic bandgap. Inspired by natural photonic crystals such as butterfly scales, a series of artificial photonic crystals are developed for use in integrated photonic platforms, biosensing, communication, and other fields. Among them, colloidal photonic crystals (CPCs) have gained widespread attention due to their excellent optical properties and advantages, such as ease of preparation and functionalization. This work reviews the classification and self‐assembly principles of CPCs, details some of the latest biomedical applications of large‐area, high‐quality CPCs prepared using advanced self‐assembly methods, summarizes the existing challenges in CPC construction and application, and anticipates future development directions and optimization strategy. With further advancements, CPCs are expected to play a more critical role in biosensors, drug delivery, cell research, and other fields, bringing significant benefits to biomedical research and clinical practice. [ABSTRACT FROM AUTHOR]

Recognition of signaling molecules for coordinated regulation of target genes is a fundamental process for biological systems. Cells often rely on transcription factors to accomplish these intricate tasks, yet the subtle conformational changes of protein structures, coupled with the complexity of intertwined protein interaction networks, pose challenges for repurposing these for bioengineering applications. This study introduces a novel platform for ligand‐responsive gene regulation, termed START (Synthetic Trans‐Acting Riboswitch with Triggering RNA). Inspired by the bacterial ligand sensing system, riboswitch, and the synthetic gene regulator, toehold switch, the START platform enables the implementation of synthetic biosensors for various ligands. Rational sequence design with targeted domain optimization yields high‐performance STARTs with a dynamic range up to 67.29‐fold and a tunable ligand sensitivity, providing a simple and intuitive strategy for sensor engineering. The START platform also exhibits modularity and composability to allow flexible genetic circuit construction, enabling seamless implementation of OR, AND, and NOT Boolean logic gates for multiple ligand inputs. The START design principle is capable of broadening the suite of synthetic biosensors for diverse chemical and protein ligands, providing a novel riboregulator chassis for synthetic biology and bioengineering applications. [ABSTRACT FROM AUTHOR]

Nonenzymatic and rapid monitoring of uric acid levels is of great value for early diagnosis, prevention, and management of oxidative stress–associated diseases. However, fast, convenient, and low‐cost uric acid detection remains challenging, especially in resource‐limited settings. In this study, a novel and rapid biosensing approach was developed for the simultaneous visualization and quantification of uric acid levels by using the unique surface plasmon resonance and photothermal property of 4,5‐diamino‐2‐thiouracil (DT)‐capped gold nanoparticles (AuNPs). With the presence of uric acid, DT‐capped AuNPs rapidly aggregated, and a visible color/photothermal change was used for uric acid quantification within 15 min. The limit of detection was determined to be 11.3 and 6.6 μM for the dual‐mode biosensor, leveraging the unique structure of DT to optimize reaction kinetics. Moreover, the sensor exhibited excellent anti‐interference capabilities and demonstrated potential for detecting a wide range of uric acid concentrations in complex samples, thereby reducing the need for extensive sample dilution and complex material synthesis procedures. Furthermore, validation against gold standard testing indicates that this biosensor could serve as a highly sensitive assay for quantifying uric acid levels in point‐of‐care applications, particularly in resource‐limited settings. [ABSTRACT FROM AUTHOR]

Antimicrobial residues in milk pose a significant risk to human health, prompting regulatory bodies to establish safety limits to protect consumers. While traditional screening methods have primarily targeted single analytes or classes, recent advancements in multiclass screening techniques offer more comprehensive and efficient monitoring. This review highlights these advancements and focuses on methods developed since 2010, such as microbial inhibition tests, immunoassays, biosensors and LC–MS‐based approaches. It also discusses the strengths and limitations of these techniques, as well as the challenges associated with analysing milk's complex matrix, emphasising the ongoing need for innovation in food safety practices. [ABSTRACT FROM AUTHOR]

As biomarkers of cancer, the accurate and sensitive detection of microRNAs is of great significance. Therefore, we proposed a surface-enhanced Raman scattering (SERS)/electrochemical (EC) dual-mode nanosensor for sensitively detecting miRNA-141. The nanosensor uses Au@Ag nanowires as a novel SERS/EC sensing platform, which has the advantages of good biocompatibility, fast response, and high sensitivity. The dual-mode nanosensor can not only effectively overcome the problem of insufficient reliability of single signal, but also realize the amplification and stable output of the detection signal, to ensure the reliability and repeatability of miRNA detection. With this sensing strategy, the target miRNA-141 can be detected over a wide linear range (100 fM to 50 nM) (LOD of 18.4 fM for SERS and 16.0 fM for electrochemical methods). In addition, the process shows good selectivity and can distinguish miRNA-141 from other interfering miRNAs. The actual analysis of human serum samples also proves that our strategy has good reliability, repeatability, and has broad application prospects in the field of analysis and detection. [ABSTRACT FROM AUTHOR]

Biosecurity encompasses the health and safety of humans, animals, plants, and the environment. In this article, "biosecurity" is defined as encompassing the comprehensive aspects of human, animal, plant, and environmental safety. Reliable biosecurity testing technology is the key point for effectively assessing biosecurity risks and ensuring biosecurity. Therefore, it is crucial to develop excellent detection technologies to detect risk factors that can affect biosecurity. An electrochemical microfluidic biosensing platform integrates fluid control, target recognition, signal transduction, and output and incorporates the advantages of electrochemical analysis technology and microfluidic technology. Thus, an electrochemical microfluidic biosensing platform, characterized by exceptional analytical sensitivity, portability, rapid analysis speed, low reagent consumption, and low risk of contamination, shows considerable promise for biosecurity detection compared to traditional, more complex, and time-consuming detection technologies. This review provides a concise introduction to electrochemical microfluidic biosensors and biosecurity. It highlights recent research advances in utilizing electrochemical microfluidic biosensing platforms to assess biosecurity risk factors. It includes the use of electrochemical microfluidic biosensors for the detection of risk factors directly endangering biosecurity (direct application: namely, risk factors directly endangering the health of human, animals, and plants) and for the detection of risk factors indirectly endangering biosecurity (indirect application: namely, risk factors endangering the safety of food and the environment). Finally, we outline the current challenges and future perspectives of electrochemical microfluidic biosensing platforms. [ABSTRACT FROM AUTHOR]

With the rapid development of society, it is of paramount importance to expeditiously assess environmental pollution and provide early warning of toxicity risks. Microbial fuel cell–based self-powered biosensors (MFC-SPBs) have emerged as a pivotal technology, obviating the necessity for external power sources and aligning with the prevailing trends toward miniaturization and simplification in biosensor development. In this case, vigorous advancements in MFC-SPBs have been acquired in past years, irrespective of whether the target identification event transpires at the anode or cathode. The present article undertakes a comprehensive review of developed MFC-SPBs, categorizing them into substrate effect and microbial activity effect based on the nature of the target identification event. Furthermore, various enhancement strategies to improve the analytical performance like accuracy and sensitivity are also outlined, along with a discussion of future research trends and application prospects of MFC-SPBs for their better developments. [ABSTRACT FROM AUTHOR]

l‐2‐Hydroxyglutarate (l‐2‐HG) is a functionally compartmentalized metabolite involved in various physiological processes. However, its subcellular distribution and mitochondrial transport remain unclear owing to technical limitations. In the present study, an ultrasensitive l‐2‐HG biosensor, sfLHGFRH, composed of circularly permuted yellow fluorescent protein and l‐2‐HG‐specific transcriptional regulator, is developed. The ability of sfLHGFRH to be used for analyzing l‐2‐HG metabolism is first determined in human embryonic kidney cells (HEK293FT) and macrophages. Then, the subcellular distribution of l‐2‐HG in HEK293FT cells and the lower abundance of mitochondrial l‐2‐HG are identified by the sfLHGFRH‐supported spatiotemporal l‐2‐HG monitoring. Finally, the role of the l‐glutamate transporter SLC1A1 in mitochondrial l‐2‐HG uptake is elucidated using sfLHGFRH. Based on the design of sfLHGFRH, another highly sensitive biosensor with a low limit of detection, sfLHGFRL, is developed for the point‐of‐care diagnosis of l‐2‐HG‐related diseases. The accumulation of l‐2‐HG in the urine of patients with kidney cancer is determined using the sfLHGFRL biosensor. [ABSTRACT FROM AUTHOR]

Optical microcavities, particularly whispering gallery mode (WGM) microcavities enhanced by plasmonic nanorods, are emerging as powerful platforms for single‐molecule sensing. However, the impact of optical forces from the plasmonic near field on analyte molecules is inadequately understood. Using a standard optoplasmonic WGM single‐molecule sensor to monitor two enzymes, both of which undergo an open‐to‐closed‐to‐open conformational transition, the work done on an enzyme by the WGM sensor as atoms of the enzyme move through the electric field gradient of the plasmonic hotspot during conformational change has been quantified. As the work done by the sensor on analyte enzymes can be modulated by varying WGM intensity, the WGM microcavity system can be used to apply free energy penalties to regulate enzyme activity at the single‐molecule level. The findings advance the understanding of optical forces in WGM single‐molecule sensing, potentially leading to the capability to precisely manipulate enzyme activity at the single‐molecule level through tailored optical modulation. [ABSTRACT FROM AUTHOR]

Enzyme‐based amperometric biosensors have become popular for healthcare applications. However, they have been under constant pressure for technological innovation to improve their sensitivity and usability. An ideal biosensor has high sensitivity and calibration‐free characteristics. This study aims to report enzyme‐based glucose and lactate sensors that utilize a proposed “time‐derivative of potential (dOCP/dt)” method, with a further aim being to prove theoretically and experimentally that dOCP/dt values are proportional to substrate concentration. High sensitivity is obtained regardless of the electrode size because the electrode potential is independent of the electrode area in the biosensor. Importantly, because the substrate diffusion determines the enzyme reaction rate on the sensors, the dOCP/dt biosensors can essentially eliminate external influences such as temperature and pH. The result is the successful realization of a biosensor that is calibration‐free, making it a much more practical option. [ABSTRACT FROM AUTHOR]

Synthetic-based fluorescent chemosensors and protein-based fluorescent biosensors are two well-established classes of tools for visualizing and monitoring biological processes in living tissues. Chemigenetic sensors, created using a combination of both synthetic parts and protein parts, are an emerging class of tools that aims to combine the strengths, and overcome the drawbacks, of traditional chemosensors and biosensors. This review will survey the landscape of strategies used for fluorescent chemigenetic sensor design. These strategies include: attachment of synthetic elements to proteins using in vitro protein conjugation; attachment of synthetic elements to proteins using autonomous protein labeling; and translational incorporation of unnatural amino acids. [Display omitted] Chemigenetic fluorescent sensors are an emerging class of biological imaging tools that incorporate both a protein and synthetic component. Tsao et al. provide an overview of how such hybrid designs have been used to create sensors with properties that could not be achieved with fully protein-based or fully synthetic alternatives. [ABSTRACT FROM AUTHOR]

Direct detection of miRNA is currently limited by the complex amplification and reverse transcription processes of existing methods, leading to low sensitivity and high operational demands. Herein, we developed a CRISPR/Cas13a-mediated photoelectrochemical (PEC) biosensing platform for direct and sensitive detection of miRNA-21. The direct and specific recognition of target miRNA-21 by crRNA-21 eliminates the need for pre-amplification and reverse transcription of miRNA-21, thereby preventing signal distortion and enhancing the sensitivity and precision of target detection. When crRNA-21 binds to miRNA-21, it activates the trans-cleavage activity of CRISPR/Cas13a, leading to the non-specific cleavage of biotin-modified DNA with uracil bases (biotin-rU-DNA). This cleavage prevents the biotin-rU-DNA from being immobilized on the electrode surface. As a result, streptavidin cannot attach to the electrode via specific biotin binding, reducing spatial resistance and causing a positively correlated increase in the photocurrent response. This Cas-PEC biosensor has good analytical capabilities, linear responses between 10 fM and 10 nM, a minimum detection limit of 9 fM, and an excellent recovery rate in the analysis of real human serum samples. This work presented an innovative solution for detecting other biomarkers in bioanalysis and clinical diagnostics. [ABSTRACT FROM AUTHOR]

The time dynamics of charge accumulation at the electrochemical interface between graphene and water is important for supercapacitors, batteries, and chemical and biological sensors. By using impedance spectroscopy, we have found that measured capacitance (Cm) at this interface with the gate voltage Vgate ≈ 0.1 V follows approximate laws Cm~T1.2 and Cm~T0.11 (T is Vgate period) in frequency ranges (1000–50,000) Hz and (0.02–300) Hz, respectively. In the first range, this dependence demonstrates that the interfacial capacitance (Cint) is only partially charged during the charging period. The observed weaker frequency dependence of the measured capacitance (Cm) at frequencies below 300 Hz is primarily determined by the molecular relaxation of the double-layer capacitance (Cdl) and by the graphene quantum capacitance (Cq), and it also implies that Cint is mostly charged. We have also found a voltage dependence of Cm below 10 Hz, which is likely related to the voltage dependence of Cq. The observation of this effect only at low frequencies indicates that Cq relaxation time is much longer than is typical for electron processes, probably due to Dirac cone reconstruction from graphene electrons with increased effective mass as a result of their quasichemical bonding with interfacial molecular charges. [ABSTRACT FROM AUTHOR]

The data‐driven machine learning technology used for neural decoding emphasizes the requirements of in vivo and in vitro neural signal acquisition with high spatial and temporal resolution. However, micro‐electrode arrays (MEAs) that simultaneously achieve high spatial and temporal resolution neural signal acquisition are not yet available. Meanwhile, the high data bandwidth of large‐scale MEA brings challenges in power consumption, data transmission, storage, and neural signal processing. This research aims to improve the spatial and temporal resolution of MEA, reduce the cost and time of large‐scale MEA customization through cascading, and reduce the bandwidth of large‐scale MEA through spike compression. Firstly, based on in‐pixel spike detection, a row‐based neural spike readout mechanism and related array circuit to improve the neural spike readout performance and temporal resolution of neural signal acquisition is proposed. To further enhance the spatial resolution and reduce the risk of large‐scale MEA fabrication, the cascading capability of the readout circuit is explored. Lastly, spatial correlation‐based neural spike encoding is proposed to reduce the data bandwidth, achieving a 5.2× compression rate. This is a study on implementing large‐scale MEA through cascaded readout circuits and novel study to utilize the spatial correlation between detected neural spikes for further compression. [ABSTRACT FROM AUTHOR]

Decoding of spatial information from place cells is currently limited to individual brain regions, severely constraining the understanding of the brain's spatial navigation mechanisms. In this study, synchronized detection of dual‐brain region spatial encoding was conducted using brain–computer interface (BCI). Therefore, an implantable microelectrode array (MEA) was developed tailored for the simultaneous detection of neuronal activities in the CA1 of the hippocampus and the Barrel Cortex (BC) of the somatosensory cortex in rats as BCI. The MEA was improved by modifying the nanocomposite PtNP/PEDOT:PSS to improve their electrical properties (reducing impedance from 1.82 ± 0.17 MΩ to 3.4 ± 0.3 kΩ), facilitating neural recordings in freely behaving rats. The neural activities were obtained from the CA1 and the BC simultaneously and validated the existence of place cells in both brain regions. This study highlighted the potential of PtNP/PEDOT:PSS‐modified MEA as BCI in concurrently detecting neural activity associated with spatial encoding in two brain regions, offering novel perspectives on the processing of tactile stimuli and the formation of cognitive maps for navigation. [ABSTRACT FROM AUTHOR]

Human-serum-albumin (HSA)-templated molecularly imprinted polymer nanoparticles (nano-MIPs) were integrated with a solution-gated field-effect transistor-based biosensor. The real-time electrical analysis of nano-MIP–HSA binding showed a high affinity and specificity of nano-MIPs for HSA. Moreover, the binding behaviour was continuously visualised using a solution-gated complementary metal-oxide semiconductor array image biosensor. [ABSTRACT FROM AUTHOR]