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This study describes a VDBA (Voltage Differencing Buffered Amplifier)-based memristor emulator and its use in an instrumentation amplifier for biomedical applications. The proposed grounded and floating memristor has been implemented using a single VDBA and grounded MOS-Capacitor. The VDBA used in this article has also been designed and uses eighteen transistors only. The proposed memristor emulator can be operated in both decremental and incremental modes. The suggested emulator's robustness has been verified using a variety of evaluations, including non-ideal inspection, variations of process corner, temperature swings, and non-volatility performance. Using 45 nm CMOS process parameters in the Cadence environment, the layout has been accomplished, and simulations and observations of the theoretical fingerprint characteristics have been made. The incremental and decremental mode of operation for grounded/floating memristor can be easily obtained by modifying the circuit slightly. The shape of the pinched-hysteresis loop is maintained up to 5 MHz. The functionality of the proposed memristor has also been tested by integrating it with the Instrumentation amplifier to amplify weak bio-medical signals.

This paper presents a novel sensor design that incorporates a microstrip patch antenna accompanied by a ground plane integrating a complementary split-ring resonator (CSRR). Integration of a circular CSRR into the microchip antenna has the potential to significantly improve radiation characteristics. The designed sensor operates at a frequency of 2.45 GHz, achieving an attenuation level of -27 dB. This design proposes the sensor's potential to function as a highly sensitive sensor by utilizing changes in the dielectric constant of biological samples. The changing dielectric constant of the analyte induces a frequency shift, allowing for the identification of different materials. Additionally, various regression algorithms based on machine learning have been employed to accurately assess the analyte's dielectric constant by studying the sensor's frequency response. Performance analysis indicates that exponential regression outperforms other approaches, showcasing a minimal root mean squared error of 0.0013. Machine learning techniques bring about substantial enhancements in sensor performance, thereby creating pathways for sophisticated applications in biochemical sensing.

This work proposes a sensitive low-temperature sensor based on the refractive index (RI) method. It uses a one-dimensional (1D) photonic crystal (PC) structure. The proposed sensor design consists of a bilayer stack of dielectric and superconductor materials. YaBa2Cu3O7 is the superconductor utilized in this case, and we consider air to be the dielectric material. The RI of air doesn’t change much with the temperature, especially compared to the superconductor material. YaBa2Cu3O7 is a superconductor that is ideal for temperature sensing applications because of its temperature-dependent RI. The sensing temperature range for the proposed sensor is 35–70K. The crucial structural factors have been precisely adjusted to increase sensing performance. Based on our knowledge, this is done to increase the sensor’s efficiency to levels that are higher than anything previously reported in the literature. Results show that the designed structure achieves an impressive RI sensitivity of 821.53nm/RIU and a temperature sensitivity of 3nm/K. This sensor could be very useful for medical applications for the detection of low temperatures. [ABSTRACT FROM AUTHOR]

The existing and emerging demand for materials for life and health has contributed to the cultivation and development of respective markets. Nevertheless, the current generation of biomedical materials has yet to fully satisfy the clinical requirements of the market, which is still in its relative infancy. Research and development in this area must be prioritized in light of the pivotal role of new life and health materials in the biological field. Among many life and health materials, GQDs, an emerging nanomaterial, exhibit considerable promise in the biomedical field, primarily due to their exceptional properties. Furthermore, the direct preparation and functionalization of GQDs have facilitated the development of specific functional composites based on GQDs. The biological applications of GQDs are undergoing rapid growth, which makes it necessary to publish a review article presenting the latest advances in this field. This review provides an overview of the significant advances in synthesizing GQDs, the techniques employed for structural characterizations, and the properties that have been elucidated. Furthermore, it presents recent findings on applying GQDs in antimicrobial, anticancer, biosensing, drug delivery, and bioimaging applications. Finally, it explores the potential of GQDs in biomedicine and biotechnology, highlighting the current challenges that remain to be addressed. [ABSTRACT FROM AUTHOR]

Magnetoelectric (ME) devices combining piezoelectric and magnetostrictive materials have emerged as powerful tools to miniaturize and enhance sensing and communication technologies. This paper examines recent developments in bulk acoustic wave (BAW) and surface acoustic wave (SAW) ME devices, which demonstrate unique capabilities in ultra-sensitive magnetic sensing, compact antennas, and quantum applications. Leveraging the mechanical resonance of BAW and SAW modes, ME sensors achieve the femto- to pico-Tesla sensitivity ideal for biomedical applications, while ME antennas, operating at acoustic resonance, allow significant size reduction, with high radiation gain and efficiency, which is suited for bandwidth-restricted applications. In addition, ME non-reciprocal magnetoacoustic devices using hybrid magnetoacoustic waves present novel solutions for RF isolation, which have also shown potential for the efficient control of quantum defects, such as negatively charged nitrogen-vacancy (NV−) centers. Continued advancements in materials and device structures are expected to further enhance ME device performance, positioning them as key components in future bio-sensing, wireless communication, and quantum information technologies. [ABSTRACT FROM AUTHOR]

This paper presents a novel sensor design that incorporates a microstrip patch antenna accompanied by a ground plane integrating a complementary split-ring resonator (CSRR). Integration of a circular CSRR into the microchip antenna has the potential to significantly improve radiation characteristics. The designed sensor operates at a frequency of 2.45 GHz, achieving an attenuation level of -27 dB. This design proposes the sensor's potential to function as a highly sensitive sensor by utilizing changes in the dielectric constant of biological samples. The changing dielectric constant of the analyte induces a frequency shift, allowing for the identification of different materials. Additionally, various regression algorithms based on machine learning have been employed to accurately assess the analyte's dielectric constant by studying the sensor's frequency response. Performance analysis indicates that exponential regression outperforms other approaches, showcasing a minimal root mean squared error of 0.0013. Machine learning techniques bring about substantial enhancements in sensor performance, thereby creating pathways for sophisticated applications in biochemical sensing. [ABSTRACT FROM AUTHOR]

A novel device structure with gate engineered recessed double gate junctionless field-effect-transistor (R_DGJLFET) has been investigated for variations in effective oxide thickness (EOT) and the optimum structure is utilized for the low power biosensing application. The device with 20 nm gate length has been designed and analyzed using ATLAS tool of SILVACO TCAD. With extensive simulation several physical parameters such as field and potential distribution, carrier concentration and conduction band energy have been analyzed along with drain current and gate-to-source capacitance. Several FOM of R_DGJLFET and conventional junctionless FET (C_DGJLFET) have been compared. It has been found that for EOT of 0.8 nm the R_DGJLFET reduces IOFF by ~ 10− 4 and the subthreshold slope is also improved. Moreover, for EOT ≤ 1 nm, the R_DGJLFET outperforms the C_DGJLFET with improved analog parameters. Furthermore, a low power biosensing application has been implemented with the proposed device. Dielectric modulation is utilized to realize the different type of biomolecules inside the cavity region of the structure. Biosensor is tuned at low voltage for better performance, which presents it as a promising contender for the future CMOS based low power sensor applications. [ABSTRACT FROM AUTHOR]

Supramolecular chemistry is a relatively new field of study that utilizes conventional chemical knowledge to produce new edges of smart materials. One such material use of supramolecular chemistry is the development of sensing platforms. Biologically relevant molecules need frequent assessment both qualitatively and quantitatively to explore several biological processes. In this review, we have discussed supramolecular sensing techniques with key examples of sensing several kinds of bio-analytes and tried to cast light on how molecular design can help in making smart materials. Moreover, how these smart materials have been finally used as sensing platforms has been discussed as well. Several useful spectroscopic, microscopic, visible, and electronic outcomes of sensor materials have been discussed, with a special emphasis on device-based applications. This kind of comprehensive discussion is necessary to widen the scope of sensing technology. [ABSTRACT FROM AUTHOR]

A simple one-pot approach for the synthesis of gold-loaded copper oxide (Au–CuOx) nanoplates was employed to develop a sensitive electrochemical surface enhanced Raman scattering (EC-SERS) substrate for the detection of anti-cancer drug hydroxycarbamide (HC). HC has been used for decades as a therapeutic agent against sickle cell anaemia and various cancers. The Au–CuOx substrate was characterized using various spectroscopic and imaging techniques, including XRD, XPS, FTIR, TEM and SEM. The electrochemical impact on the SERS-based sensing capability was investigated by immobilizing the bimetallic material on a conductive glass support acting as a working electrode. First-principle calculations were carried out to predict the electrostatic properties, electron transfer contribution and adsorption energetics of HC molecules on the nanostructured surface. Spectroscopic and theoretical investigations suggested that Au-loaded copper oxide exhibits inherent surface plasmon resonance (SPR) properties that can be notably enhanced by incorporating the electrochemical factor. Several prominent Raman peaks associated with HC and ascribed by the NCN bending, CN stretching, NO stretching, CO stretching, and NH2 wagging vibrational modes showed substantial enhancements upon the electrochemically induced interaction between the SERS substrate and the drug molecules. A limit of detection of one-tenth of nanomolar concentration could be achieved under optimum conditions. The presented methodology could be potential in the context of biomedical laboratories for the sake of quick and reliable assessment. [ABSTRACT FROM AUTHOR]

Supramolecular chemistry is a relatively new field of study that utilizes conventional chemical knowledge to produce new edges of smart materials. One such material use of supramolecular chemistry is the development of sensing platforms. Biologically relevant molecules need frequent assessment both qualitatively and quantitatively to explore several biological processes. In this review, we have discussed supramolecular sensing techniques with key examples of sensing several kinds of bio-analytes and tried to cast light on how molecular design can help in making smart materials. Moreover, how these smart materials have been finally used as sensing platforms has been discussed as well. Several useful spectroscopic, microscopic, visible, and electronic outcomes of sensor materials have been discussed, with a special emphasis on device-based applications. This kind of comprehensive discussion is necessary to widen the scope of sensing technology.

The investigation of molecules in the mid-IR spectral range has revolutionized our understanding in many fields such as atmospheric chemistry and environmental sensing for climate research or disease monitoring in medical diagnosis. While the mid-IR analysis of gas-samples is already a mature discipline, the spectroscopy of liquids is still in its infancy. However, it is a rapidly developing field of research, set to fundamentally change our knowledge of dynamical processes of molecules in liquid-phase. In this field, mid-IR plasmonics has emerged as breakthrough concept for miniaturization, enabling highly-sensitive and -selective liquid measurement tools. In this review, we give an overview over current trends and recent developments in the field of mid-IR spectroscopy of molecules in liquid phase. Special attention is given to plasmon-enhanced concepts that allow measurements in highly compact sensor schemes. Nowadays, they reach full monolithic integration, including laser, interaction section and detector on the same chip, demonstrating unprecedented operation in situ and real-time analysis of chemical processes. [ABSTRACT FROM AUTHOR]

Nanomedicine showed the unique benefits in clinical outcomes in comparison with traditional and conventional drugs in the treatment of cancer. In the future, nanomedicine therapy seems to pave the way for new treatments in cancer. In this regard, silica nanoparticles are used in various fields of technology, biomedicine and biosensing techniques due to their unique properties such as stability, biocompatibility, high surface area, significant reactivity and functionalizability. Although there are various physical and chemical methods for synthesizing silica nanoparticles, its synthesis by green method has other significant features such as being environmentally friendly, cost-effective, saving time and eliminating toxic compounds and harmful by-products that increase their application in the field of biomedicine. In the method of green synthesis of silica nanoparticles, various sources such as plants, fungi, bacteria, yeast, actinomycetes, etc. are used. In this narraitive review, various biomedical applications of green synthesized silica nanoparticles are discussed along with their examples. [ABSTRACT FROM AUTHOR]

The low-frequency (terahertz) vibrational spectroscopy has been investigated experimentally for two chlorophyll species, Chl-a and one of its magnesium derivatives (Chl-Mg-Na). The combination of terahertz time-domain spectroscopy and Fourier transform infrared spectroscopy has enabled a broad frequency range to be covered (0.2 to 18 THz). For Chl-Mg-Na, the terahertz spectra show clear and well-marked features at 1.44, 1.64, and 1.83 THz dominated by intermolecular interactions. The frequency dependent refractive index and absorption coefficient of Chl-Mg-Na were both determined using the Fit@TDS software. Below 1.0 THz, a refractive index of 2.09 was measured. In order to acquire further understanding of the observed vibrational modes, a detailed study of the temperature dependence of the line positions of the lowest modes in Chl-Mg-Na was performed. As the temperature was increased from 88 K to 298 K, the feature at 1.83 THz experienced a notable red shift of frequency and line shape broadening, whereas the feature at 1.44 THz showed little change. These results suggest that the 1.83 THz feature is dominated by intermolecular motions occurring over the crystalline unit cell of the Chl-Mg-Na molecular crystal. Finally, terahertz time-domain spectroscopy was used to acquire the spectra of an ornamental plant bearing yellow-green variegated leaves (ivy, Aureomarginata variety), the yellow sectors having lower chlorophyll content compared to the green sectors. In dehydrated green tissue, the chlorophyll molecules showed well-marked intermolecular vibrational modes at 1.86 THz, indicating that chlorophyll molecules are prone to packing with an ordered molecular arrangement. These results demonstrate the potential application of THz spectroscopy in the field of agronomy. [ABSTRACT FROM AUTHOR]

As choline levels can be associated with several diseases such as Alzheimer's, Parkinson's, and so on, monitoring the choline levels has great importance. In this study, a metal–organic framework (Cu-MOF) with peroxidase-like activity was synthesized through the employment of an organic amine as a template and used as an efficient immobilization matrix for choline oxidase (ChOx). The Km values of Cu-MOF toward TMB and H2O2 are 1.4 mM and 0.084 mM, respectively. Results showed that the optimal pH for the ChOx@Cu-MOF complex in the presence of choline was obtained 5.5 in which it showed the high activity from 40 to 55 °C. Reusability studies showed that the residual activity of the ChOx@Cu-MOF complex toward choline had no apparent reduction up to five cycles of reusing. In comparison, it can maintain about 80% of the initial activity after ten cycles of reusing. Furthermore, this system displayed a robust linear relationship from 0.2 to 250 µM of choline with a detection limit of 0.2 μM. The obtained results showed that the recovery of these samples ranged between 95.07 and 102.77%. This strategy provides a rapid and facile approach to construct stable and functional biocatalysts, which have great promise for applications in bio-sensing and industrial catalysis. [ABSTRACT FROM AUTHOR]

Microorganisms hosted in abiotic structures have led to engineered living materials that can grow, sense, and adapt in ways that mimic biological systems. Although porous structures should favor colonization by microorganisms, they have not yet been exploited as abiotic scaffolds for the development of living materials. Here, porous ceramics are reported that are colonized by bacteria to form an engineered living material with self-regulated and genetically programmable carbon capture and gas-sensing functionalities. The carbon capture capability is achieved using wild-type photosynthetic cyanobacteria, whereas the gas-sensing function is generated utilizing genetically engineered E. coli. Hierarchical porous clay is used as a ceramic scaffold and evaluated in terms of bacterial growth, water uptake, and mechanical properties. Using state-of-the-art chemical analysis techniques, the ability of the living porous ceramics are demonstrated to capture CO 2 directly from the air and to metabolically turn minute amounts of toxic gas into a benign scent detectable by humans., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

The present paper reports on a Finite Element Method (FEM) analysis of the experimental situation corresponding to the measurement of the temperature variation in a single cell plated on bulk diamond by means of optical techniques. Starting from previous experimental results, we have determined—in a uniform power density approximation and under steady-state conditions—the total heat power that has to be dissipated by a single cell plated on a glassy substrate in order to induce the typical maximum temperature increase ΔTglass=1 K. While keeping all of the other parameters constant, the glassy substrate has been replaced by a diamond plate. The FEM analysis shows that, in this case, the maximum temperature increase is expected at the diamond/cell interface and is as small as ΔTdiam=4.6×10−4 K. We have also calculated the typical decay time in the transient scenario, which resulted in τ≈ 250 μs. By comparing these results with the state-of-the-art sensitivity values, we prove that the potential advantages of a longer coherence time, better spectral properties, and the use of special field alignments do not justify the use of diamond substrates in their bulk form.

Poly(α-l-lysine) (PLL) is a class of water-soluble, cationic biopolymer composed of α-l-lysine structural units. The previous decade witnessed tremendous progress in the synthesis and biomedical applications of PLL and its composites. PLL-based polymers and copolymers, till date, have been extensively explored in the contexts such as antibacterial agents, gene/drug/protein delivery systems, bio-sensing, bio-imaging, and tissue engineering. This review aims to summarize the recent advances in PLL-based nanomaterials in these biomedical fields over the last decade. The review first describes the synthesis of PLL and its derivatives, followed by the main text of their recent biomedical applications and translational studies. Finally, the challenges and perspectives of PLL-based nanomaterials in biomedical fields are addressed.

Among the wide range of chemosensors, the development of fluorescent chemosensors has shown continued interest in the domains of chemistry, materials, biology, and ecology due to their simple operation, low cost, high sensitivity, specificity, live observation, and short response time. As a metal‐free and fluorescent chemosensor, graphitic carbon nitride (g‐C3N4) has emerged as a new research hotspot and received widespread interdisciplinary attention which is attributable to its favorable electrical band structure, high physicochemical stability, and "earth‐abundant" nature. This review summarizes the structure, synthetic methods, and various techniques for the modification of g‐C3N4. This review also covers the development of g‐C3N4 nanomaterials‐based sensors and their potential applications in a variety of fields. Furthermore, the comparative performance of various sensors, existing obstacles, and perspectives of g‐C3N4‐based nanomaterials are also outlined in detail. [ABSTRACT FROM AUTHOR]

Graphene can be used as a starting material for the synthesis of useful nano-complexes for flexible, transparent electrodes, therapeutic, bio-diagnostics, and bio-sensing. In order to apply graphene in the medical field, the chemical vapor deposition (CVD) method has been mainly utilized considering its large and near-homogeneous carbon constituents. Especially, the less degree of perturbation of graphene monolayer (GM), which is followed by the underneath catalytic Cu surface morphology, is very crucial in terms of providing the suspended GM and relatively fluent lateral carrier mobility with lower sheet resistance value. In this work, we can suggest a surface-enhanced Raman spectroscopic (SERS) indicator in a quantitative way on the status of z-directional morphological corrugation of a CVD-grown GM (CVD-GM) by applying a nanoparticle-on-mirror (NPoM) system composed of Au nanoparticle (NP)/CVD-GM/Au thin film (TF) plasmonic junction structure. A new (or enhanced) radial breathing-like mode (RBLM) SERS signal around ~ 150 cm−1 from CVD-GM spaced in NPoM is clearly observed by employing a local z-polarized incident field formed at the Au NP–Au TF plasmonic gap junctions. With this observation, the value of I[out-of-plane, RBLM]/I[in-plane, [2D] at certain domains, can be suggested as a new optical nano-metrology value to relatively determine between lower z-directional morphological corrugation (or protrusion) status of a CVD-GM spaced in our NPoM system (lower I[RBLM]/I[2D] value) and a higher degree of lateral carrier mobility of the CVD-GM associated with lower sheet resistance values as a result of higher blue-shifted Raman in-plane (G, 2D) peak maximum position. Furthermore, we will also expect the bio-sensing performances by utilizing the high specific surface area and ultrahigh flexibility of the CVD-GM in one of the future prospective works such as pressure-strain, strain-to-electricity, and chemical-coupled sensor via I[RBLM]/I[2D] values. [ABSTRACT FROM AUTHOR]

Aptamer‐based hydrogels have drawn great attention due to their biocompatibility, mechanical properties, responsiveness, and stability. Aptamers are utilized to obtain specific molecular recognition. Aptamers are short single‐stranded DNA (ssDNA) or RNA molecules selected through systematic evolution of ligands by exponential enrichment (SELEX) process, to bind to a specific target with high affinity and specificity. Aptamer functionalized hydrogels have become popular in a wide range of promising applications with the advantages of a vast target distribution, good stability, easy modification, and low cost. In this review, the recent progress on aptamer functionalized hydrogels including their design, fabrication, and bio‐sensing applications have been summarized. The prospects and challenges have also been discussed. [ABSTRACT FROM AUTHOR]

Today, quantitative and qualitative diagnosis of choline is clinically essential. One way to deal with the limitations of traditional methods is using the bimetallic metal–organic framework (MOF)/enzyme-based biosensors. Unlike single metal, the bimetallic MOFs have important properties such as increasing MOF peroxidation like activity, increasing the stability, and maintenance of the enzyme in the MOF structure, etc. In this research, a biosensor system based on MOF‏(Fe–Cu)–ChOx is designed for colorimetric detection of choline. Our results showed that the optimum pH and temperature for the peroxidase-like activity of MOF-enzyme complex were 5.5 and 25–40‏ °C, respectively. Also, the linear area and the detection limit of this biosensor were 20–200 and 0.006 micromoles, respectively. The obtained recovery in the human serum choline assay was in the range of 95.15–103.1%, which, compared to other similar biosensors, shows the sensitivity, specificity, and reliability of the biosensor in biological samples. These results indicated that the synthesized peroxidase-mimicking MOF‏(Fe–Cu) could stabilize the choline oxidase and sense choline in the biological fluids. [ABSTRACT FROM AUTHOR]

We present a novel multi-modal bio-sensing platform capable of integratingmultiple data streams for use in real-time applications. The system is composedof a central compute module and a companion headset. The compute node collects,time-stamps and transmits the data while also providing an interface for a widerange of sensors including electroencephalogram, photoplethysmogram,electrocardiogram, and eye gaze among others. The companion headset containsthe gaze tracking cameras. By integrating many of the measurements systems intoan accessible package, we are able to explore previously unanswerable questionsranging from open-environment interactions to emotional response studies.Though some of the integrated sensors are designed from the ground-up to fitinto a compact form factor, we validate the accuracy of the sensors and findthat they perform similarly to, and in some cases better than, alternatives.

The current methods of water quality monitoring tend to be costly, labor-intensive, and off-site. Also, they are not energetically sustainable and often require environmentally damaging power sources such as batteries. Microbial fuel cell (MFC) technology is a promising sustainable alternative to combat these issues due to its low cost, eco-friendly energy generation, and bio-sensing features. Extensive work has been done on using MFCs as bio-sensors or sources of power separately. However, little work has been done toward using MFCs for both applications at the same time. Additionally, previous studies using MFCs for water quality measurement have been mostly limited to laboratory conditions due to the biochemical complexity of the real-world. Another limitation of MFCs is how little power they can generate, requiring the MFC-based systems to have minimal power consumption. This work addresses these challenges and presents an energy-autonomous water quality sensing unit that uses a single MFC both as its sensory input and the sole source of power for computing the chemical oxygen demand (COD). In the proposed unit, geometric features of the voltage profile of the MFC (e.g., peak heights) are used as the inputs to a machine learning algorithm (support vector regression (SVR)). The electrical power generated by the MFC is used to drive a low-power microcontroller which logs the MFC voltage and runs the machine learning algorithm. Experimental evaluation showed that the device is capable of detecting the COD of natural pond water samples accurately (coefficient of determination $(R^{2})=0.94$ ). This work is the first demonstration of energy autonomy in an MFC-based sensing unit for measuring water quality and represents a step forward in the development of energy-autonomous sensors for environmental monitoring applications.

These days, carbon dots (CDs) are the rising stars of nanomaterials. Carbon dots (CDs) are small carbon nanoparticles with the same type of surface passivation (less than 10 nm in size). Researchers found C-dots by accident while purifying single-walled carbon nanotubes (SWCNTs) manufactured using the arc-discharge process. Toxic metal-based quantum dots are being replaced with carbon dots (QDs). Carbon dots are currently being prepared from a variety of natural resources in order to obtain self-passivated products at a reasonable cost. Because of their superior photo physical characteristics, biocompatibility, and low toxicity, carbon dots have prospective applications in bio sensing, bio imaging, and drug administration. Different synthetic processes, precursors, salient properties, and applications were reviewed in this review, as well as some future prospects, obstacles, and possible solutions for future development. Because of their tunable optical characteristics and better biocompatibility, luminous carbon-based nanomaterials have sparked a lot of scientific interest. Different light emission properties of carbon are discussed in this review. Distinct synthesis procedures have resulted in different carbon dots (CDs). Summarized here. The optical properties of CDs that haven't been synthesized yet surface doping and element doping can be used to further control it. CDs are being functionalized for an adjustable band gap. As a result of their luminescent with reduced cytotoxicity and tunable optical characteristics CDs have been thoroughly investigated in terms of their potential uses in biomedicine, such as analytical sensors, and instruments for bioimaging. Fluorescent carbon dots are a new type of nanomaterial from the carbon family. Green CDs, which have attracted a lot of attention from researchers because of their better water solubility, high biocompatibility, and eco-friendly nature when compared to chemically generated CDs, can be made from a variety of inexpensive and renewable resources. The presence of heteroatoms on the surface of green CDs in the form of amine, hydroxyl, carboxyl, or thiol functional groups, which can improve their physicochemical qualities, quantum yield, and likelihood of visible light absorption, eliminates the need for additional surface passivation. [ABSTRACT FROM AUTHOR]

Pathogenic bacteria and several biomolecules produced by cells and living organisms are common biological components posing a harmful threat to global health. Several studies have devised methods for the detection of varying pathogenic bacteria and biomolecules in different settings such as food, water, soil, among others. Some of the detection studies highlighting target pathogenic bacteria and biomolecules, mechanisms of detection, colorimetric outputs, and detection limits have been summarized in this review. In the last 2 decades, studies have harnessed various nanotechnology-based methods for the detection of pathogenic bacteria and biomolecules with much attention on functionalization techniques. This review considers the detection mechanisms, colorimetric prowess of bio-receptors and compares the reported detection efficiency for some bio-receptor functionalized nanoparticles. Some studies reported visual, rapid, and high-intensity colorimetric detection of pathogenic bacteria and biomolecules at a very low concentration of the analyte. Other studies reported slight colorimetric detection only with a large concentration of an analyte. The effectiveness of bio-receptor functionalized nanoparticles as detection component varies depending on their selectivity, specificity, and the binding interaction exhibited by nanoparticles, bio-receptor, and analytes to form a bio-sensing complex. It is however important to note that the colorimetric properties of some bio-receptor functionalized nanoparticles have shown strong and brilliant potential for real-time and visual-aided diagnostic results, not only to assess food and water quality but also for environmental monitoring of pathogenic bacteria and a wide array of biomolecules.

This article investigates the remediating effect of bio-sensing technology on touch practices in the context of parent-infant interaction. We examine how the entry of a biosensing technology into the social, sensory and technological ecology of family homes interacts with the ways in which parents and babies know each other and communicate through touch. The paper centres on an exploratory case study of the Owlet Smart Sock (OSS), a bio-sensing baby monitoring device. We bring the social critical and experiential lenses of multimodality and sensory ethnography to studying the OSS as a socio-technological probe across a range of research encounters, including focus groups, home visits and video re-enactments with parents. In doing so, we provide an account of the ways in which the technology affects how babies and parents' bodies are (re)imagined, assessed, controlled, interrelated, experienced, and cared for and move beyond generic social debate around the quantified-objectified baby and fears of touch deprivation in contemporary digital culture. [ABSTRACT FROM AUTHOR]

In recent years, the use of bio-sensing signals such as electroencephalogram (EEG), electrocardiogram (ECG), etc. have garnered interest towards applications in affective computing. The parallel trend of deep-learning has led to a huge leap in performance towards solving various vision-based research problems such as object detection. Yet, these advances in deep-learning have not adequately translated into bio-sensing research. This work applies novel deep-learning-based methods to various bio-sensing and video data of four publicly available multi-modal emotion datasets. For each dataset, we first individually evaluate the emotion-classification performance obtained by each modality. We then evaluate the performance obtained by fusing the features from these modalities. We show that our algorithms outperform the results reported by other studies for emotion/valence/arousal/liking classification on DEAP and MAHNOB-HCI datasets and set up benchmarks for the newer AMIGOS and DREAMER datasets. We also evaluate the performance of our algorithms by combining the datasets and by using transfer learning to show that the proposed method overcomes the inconsistencies between the datasets. Hence, we do a thorough analysis of multi-modal affective data from more than 120 subjects and 2,800 trials. Finally, utilizing a convolution-deconvolution network, we propose a new technique towards identifying salient brain regions corresponding to various affective states. [ABSTRACT FROM AUTHOR]

Plasmonic‐based sensing revolves around the generation of plasmons as a result of light–matter interactions. Analytical and/or diagnostic technologies based on this principle are extremely successful and popular in the bio‐medical industry due to their high sensitivity as well as real‐time and label‐free sensing capabilities. Employing 2D multilayers as the main plasmonic substrate instead of pure metals is a relatively new concept that can provide advantages for the surface plasmon resonance (SPR) sensor. In this work, the gain in sensitivity of the Au–Ag based SPR sensors is evaluated by employing 2D materials like graphene, MoS2, and WS2 in a multilayer SPR system. The simulations calculate the sensitivity of such multi‐layered SPR structures and indicate that the use of WS2 in the modified system can lead to an increased sensitivity (1.53 times) as compared to the standard Au‐based Kretschmann configuration. [ABSTRACT FROM AUTHOR]

As an ideal substitute for traditional organic fluorescent dyes or up-conversion nanomaterials, copper nanoclusters (CuNCs) have developed rapidly and have been involved in exciting achievements in versatile applications. The emergence of novel CuNCs composites improves the poor stability and fluorescence intensity of CuNCs. With this in mind, great efforts have been made to develop a wide variety of CuNCs composites, and impressive progress has been made in the past few years. In this review, we systematically summarize absorption, fluorescence, electrochemiluminescence, and catalytic properties and focus on the multiple factors that affect the fluorescence properties of CuNCs. The fluorescence properties of CuNCs are discussed from the point of view of core size, surface ligands, self-assembly, metal defects, pH, solvent, ions, metal doping, and confinement effect. Especially, we illustrate the research progress and representative applications of CuNCs composites in bio-related fields, which have received considerable interests in the past years. Additionally, the sensing mechanism of CuNCs composites is highlighted. Finally, we summarize current challenges and look forward to the future development of CuNCs composites. Schematic diagram of the categories, possible sensing mechanisms, and bio-related applications of copper nanoclusters composites. [ABSTRACT FROM AUTHOR]

In this manuscript, an analytical model has been demonstrated for Dielectric Modulated Junctionless Biotube FET (DM-JL-BT-FET) as a sensor. The Junctionless Biotube FET based sensor has been compared with Nanowire FET under similar bio-molecule conditions. It has been demonstrated that Dielectric Modulated Junctionless Biotube FET shows much higher efficiency in Bio-sensing and poses superior device performance characteristic in terms of higher sensitivity, higher drift in drain current, transconductance, Ion/Ioff ratio, Subthreshold Slope and Threshold voltage. The hole concentrations have also been investigated under different biomolecule conditions. Two different biomolecule conditions have been considered in our analysis viz., firstly, varying the biomolecule concentrations and secondly, inserting different biomolecules namely DNA, Biotin and Hydroprotein. Improved bio sensing is observed in Junctionless Biotube FET because of superlative gate control over the channel, owing to architecture of Biotube FET. The analytical results have also been modelled for DM-JL-BT-FET by finding a solution to the 2-D Poisson equation in accordance with the boundary conditions. The analytical results are much in coherence with the results obtained from the simulator. [ABSTRACT FROM AUTHOR]

Surface Electromyography (sEMG) is the non-invasive measurement of skeletal muscle contraction bio-potentials. Measuring sEMG of a stimulated muscle can prove particularly difficult due to large scale and long lasting stimulation-induced artefacts: if an sEMG device does not account for such artefacts, its measurements can be swamped and components damaged. sEMG has been used in a wide range of clinical and biomedical fields, providing measures such as muscular fatigue and subject intent. The recording of sEMG can prove difficult due to signal contamination such as movement artefact and mains interference.There are very few commercial sEMG devices that contain protection against large stimulation voltages or measures to reduce artefact transient times. Furthermore, most commercial or research level designs are not open source; these designs are effectively an inflexible black box to researchers and developers.This research presents the design, test and validation of an open source sEMG design, able to record muscle bio-potentials concurrently to electrical stimulation. The open source, low-cost nature of the design provides accessibility to researchers without the time and cost associated with design development. The design has been tested on the forearms of four able-bodied subjects during 25 Hz constant current stimulation, and has been shown to record subject volitional sEMG and M-wave without saturation.

Modern neuromodulation systems typically provide a large number of recording and stimulation channels, which reduces the available power and area budget per channel. To maintain the necessary input-referred noise performance despite growingly rigorous area constraints, chopped neural front-ends are often the modality of choice, as chopper-stabilization allows to simultaneously improve (1/f) noise and area consumption. The resulting issue of a drastically reduced input impedance has been addressed in prior art by impedance boosters based on voltage buffers at the input. These buffers precharge the large input capacitors, reduce the charge drawn from the electrodes and effectively boost the input impedance. Offset on these buffers directly translates into charge-transfer to the electrodes, which can accelerate electrode aging. To tackle this issue, a voltage buffer with ultra-low time-averaged offset is proposed, which cancels offset by periodic reconfiguration, thereby minimizing unintended charge transfer. This article explains the background and circuit design in detail and presents measurement results of a prototype implemented in a 180 nm HV CMOS process. The measurements confirm that signal-independent, buffer offset induced charge transfer occurs and can be mitigated by the presented buffer reconfiguration without adversely affecting the operation of the input impedance booster. The presented neural recorder front-end achieves state of the art performance with an area consumption of 0.036 mm2, an input referred noise of 1.32 μVrms (1 to 200 Hz) and 3.36 μVrms (0.2 to 10 kHz), power consumption of 13.7 μW from 1.8 V supply, as well as CMRR and PSRR ≥ 83 dB at 50 Hz. [ABSTRACT FROM AUTHOR]

[Display omitted] In contrast to the conventional ocular formulations, contact lenses are well known for their diverse applications ranging from bio-sensing, prevention of myopia, cosmetics, and drug delivery. With a tremendous change in the lifestyle, contact lenses for therapeutic purposes have increased several fold. Contact lenses as medicated lenses suffer from several disadvantages, and to overcome the same numerous approaches have been explored. Researches worldwide have come a long way from cyclodextrin-based and vitamin E-based modified contact lenses to bioinspired approaches to enhance the effectiveness of the drug-eluting contact lenses. The bioinspired approach exploits bioinspired polymeric systems to enhance biocompatibility, specific molecule recognition technique by molecular imprinting, or stimuli-responsive system to improve the biocompatibility, drug loading, and drug delivery efficacy of the drug-eluting contact lenses. Moreover, recent innovations in ocular therapeutics such as nanowafers and microneedle contact lenses, and ocular patches have gained tremendous attention in ocular therapeutics. Another potential application of the contact lenses are smart lenses applied in the biosensing and diagnosis of various ocular disorders. The review summarizes and discusses the widespread therapeutic applications of next-generation contact lenses and various fabrication approaches, including its clinical implications, efforts taken by researchers in exploring the novel materials and diverse forms of the lenses, mechanisms of drug release, clinical trials, and their toxicity and safety concerns. [ABSTRACT FROM AUTHOR]

Near‐infrared (NIR) phosphors have gained a substantial amount of attention in the past few years simply due to their numerous applications. Recent publications have reported interesting findings regarding the fundamentals of phosphors. However, the unclear application of these phosphors limits their potential. This mini review aims to provide insights for researchers regarding the potential applications of NIR phosphors and their perspectives for further development of NIR phosphor technology. [ABSTRACT FROM AUTHOR]

Multi-band metamaterial absorbers (MMAs) are widely used in detecting and sensing fields to achieve selective frequency detection. In this study, a triple-narrowband absorber based on a symmetrical dual-trident structure is numerically designed for high absorption and sensing applications in the terahertz region. Simulation results show that the maximum absorptivity of three distinctive narrow-band absorption peaks is up to 99.94% and any of the three resonance frequencies can be utilized for bio-sensing. According to bio-sensing detection, the proposed sensor can simultaneously detect the thickness and refractive index of an unknown layer by utilizing different frequency shifts of the three resonance absorption peaks. The deviation of RI and thickness is 0.075 and zero, respectively. Results show that such a simple designed absorber could provide a desirable promising for terahertz-wave absorption and sensing applications. [ABSTRACT FROM AUTHOR]

As most of the bio-molecules sizes are comparable to the terahertz (THz) wavelength, this frequency range has spurred great attention for bio-medical and bio-sensing applications. Utilizing such capabilities of THz electromagnetic wave, this paper presents the design and analysis of a new non-intrusive and label-free THz bio-sensor for aqueous bio-samples using the microfluidic approach with real-time monitoring. The proposed THz sensor unit utilizes the highly confined feature of the localized spoof surface plasmon (LSSP) resonator to get high sensitivity for any minute change in the dielectric value near it's surface. The proposed sensor, which is designed at 1 THz, exploits the reflection behavior (S11) of the LSSP resonator as the sensing response. The proposed sensor has been designed with a high-quality factor of 192 to obtain a high sensitivity of 13.5 MHz/mgml-1. To validate the proposed concept, a similar sensor unit has been designed and implemented at microwave frequency owing to the geometry dependent characteristics of the LSSP. The developed sensor has got a highly sensitive response at microwave frequency with a sensitivity of 1.2771e-4 MHz/mgml-1. A customized read-out circuitry is also designed and developed to get the sensor response in terms of DC-voltage and to provide a proof of concept for the low-cost point of care (PoC) detection solution using the proposed sensor. It is anticipated that the proposed design of highly sensitive sensor will pave a path to develop lab-on-chip systems for bio-sensing applications. [ABSTRACT FROM AUTHOR]

This manuscript presents a robust strategy for selective Pb(II) sensing based on a fluorescence turn‐off mechanism using ZnS quantum dots (QDs) biosynthesized using Aspergillus sp. The biogenic nanoprobe displayed marked sensing efficiency in the presence of Pb ions over concentration ranges from 5 to 100 μM with limits of detection of around 2.45 μM. Performance optimization studies revealed that the maximum fluorescence quenching efficiency was obtained in the presence of [ZnS NPs] at 4 mg/ml, and alkaline pH of 10 recorded under stable ambient temperature for approximately 5 min for the quenching process. Advanced morphological analysis indicated that the bio‐sensing mechanism was essentially a surface‐based phenomenon in which the Pb ions were in very close proximity to the QDs and formed stable ground‐state Pb–ZnS complexes, resulting in a quenched fluorescence of the QDs. Simultaneously, a larger fraction of Pb ions interacted via collisions with the excited ZnS QDs and resulted in an effective energy transfer from the excited QDs to the Pb ions, therefore resulting in an obvious decrease in QD fluorescence. These insights were well supported by theoretical analysis using Stern–Volmer plots and sphere‐of‐action models. [ABSTRACT FROM AUTHOR]