1,720,991 research outputs found
Advanced Nanocomposite-Based Electrochemical Sensor for Ultra-Sensitive Dopamine Detection in Physiological Fluids
Full text linkThis study presents a novel point-of-care electrochemical sensor for dopamine (DA) detection, featuring a flexible laser-induced graphene (LIG) modified with a unique nanocomposite comprising Nb4C3Tx MXene, polypyrrole (PPy), and iron nanoparticles (FeNPs). The LIG-Nb4C3Tx MXene-PPy-FeNPs is characterized by scanning electron microscopy to confirm the successful surface modification. The electrochemical performance of the fabricated sensor via cyclic voltammetry showed significant electrochemical activity upon Nb4C3Tx MXene-PPy-FeNPs nanocomposite modification of the LIG surface with an increased peak anodic current (Ipa) from 43 μA to 104 μA. The sensor demonstrated high electrocatalytic activity and a wide linear detection range of 1 nM to 1 mM DA with excellent sensitivity of 0.283 μA/nM cm−2, and an ultralow detection limit of 70 pM. The LIG-Nb4C3Tx MXene-PPy-FeNPs sensor exhibited good recovery in biological samples and a remarkable selectivity for DA, effectively distinguishing it from common interfering compounds such as uric acid, ascorbic acid, glucose, sodium chloride, and their mixtures. This flexible LIG-Nb4C3Tx MXene-PPy-FeNPs sensor platform provides a reliable and accurate approach for detecting DA, even in complex biological matrices at point-of-care applications highlighting its potential for advanced biosensing applications
Electrochemical and Nanomaterial Based Strategies for Nonenzymatic Glucose Detection: A Review
No full textElectrochemical glucose sensing technologies have undergone significant evolution, with continual advancements aimed at improving sensitivity, selectivity, and user convenience. This review systematically explores the development of emerging nonenzymatic glucose sensor designs. Nonenzymatic sensors are critically evaluated for their ability to overcome enzymatic limitations, leveraging novel materials and catalytic mechanisms. Additionally, the emergence of smartphone-integrated glucose monitoring systems is highlighted as the fifth generation, representing a paradigm shift toward personalized, real-time healthcare management. Emphasis is placed on the strategies employed to reduce the working electrode potential and enhance analytical performance. Key analytical metrics and real-sample applicability are evaluated, and persistent challenges including reliability, biocompatibility, and calibration-free operation are identified. Further, this review provides a critical perspective on the trajectory of electrochemical nonenzymatic glucose sensor technologies and outlines future directions toward the development of next-generation platforms for continuous and noninvasive glucose monitoring
Wireless bipotentiostat circuit for glucose and H2O2 interrogation
No full textHere we present a cost-effective point-of-use wireless platform for the electrochemical detection of low concentrations of glucose and hydrogen peroxide (H2O2) simultaneously. The electrochemical system utilizes a dual sensor integrated with a portable bipotentiostat. The bipotentiostat hardware implements a basic design that reduces the cost of construction and increases the affordability of the instrument, while providing similar functionality to the more expensive bench-top potentiostats. The bipotentiostat utilizes inexpensive components, common Ag/AgCl reference and platinum counter electrodes, two working electrodes, and it is designed to detect currents within the range of 20 uA to 7 mA. Additionally, the bipotentiostat is integrated with wireless module ESP8266 that interfaces with a smartphone to enable real-time monitoring and visualization of the analyte concentration levels. The results show that the self-designed bipotentiostat is capable of performing chronoamperometry and demonstrate an electrochemical detection system that is a portable alternative system for laboratory and point-of-use testing
Flexible Cu Nanostructured Laser-Induced Graphene Electrodes for Highly Sensitive and Non-Invasive Lactate Detection in Saliva
No full textA scalable and facile fabrication strategy is presented for developing a flexible, nanostructured, non-enzymatic electrochemical sensor for lactate detection based on copper-modified laser-induced graphene (CuNPs/LIG). A one-step electrodeposition process was employed to uniformly decorate the porous LIG framework with copper nanostructures, offering a cost-effective and reproducible approach for constructing enzyme-free sensing platforms. Scanning electron microscopy and energy-dispersive X-ray spectroscopy confirmed dense Cu nanostructure loading and efficient interfacial integration across the conductive LIG surface. The resulting CuNPs/LIG electrode exhibited excellent electrocatalytic performance, achieving a sensitivity of 8.56 μA µM−¹ cm−² with a low detection limit of 42.65 μM and a linear response toward lactate concentrations ranging from 100 to 1100 μM in artificial saliva under physiological conditions. The sensor maintained high selectivity in the presence of physiologically relevant interferents. Practical applicability was demonstrated through recovery studies, where recovery rates exceeding 104% showcase the sensor’s analytical reliability in complex biological matrices. Overall, this work establishes a robust, sensitive, and cost-efficient Cu-nanostructured LIG sensing platform, offering strong potential for non-invasive lactate monitoring in real-world biomedical and wearable applications
Self-Powered Glucose Biosensing System
No full textIn this dissertations, we designed and developed a novel self-powered glucose biosensor (SPGS) system that can simultaneously sense blood glucose and generate bioelectricity to power implantable bioelectronics. We characterize the power generation and biosensing capabilities in the presence of glucose analyte. The system comprises a biofuel cell employing bioelectrodes composed of a compressed network of three-dimensional multi-walled carbon nanotubes (MWCNTs) with immobilized redox enzymes, pyroquinoline quinone glucose dehydrogenase (PQQ-GDH) and bilirubin oxidase (BODX) functioning as the anodic and cathodic catalyst, respectively. The overall dimension of the biofuel cell prototype was 5 mm x 5 mm yielding an active surface area of 0.04 cm2. When operated in 20 mM glucose, the biofuel cell exhibited an open circuit voltage and power density of 552.37 mV and 0.225 mW/cm2 at 285.46 mV, respectively, with a current density of 1.285 mA/cm2. Moreover, at physiological glucose concentration (5 mM), the biofuel cell exhibits an open circuit voltage and power density of 391.36 mV and 84.64 �W/cm2 at 214.3 mV, respectively, with a current density of 602.5 �A/cm2. This micropower harvested by a single glucose biofuel cell is only practical for powering micropower devices and the power produced is linearly correlated with glucose over a dynamic range of 3 - 20 mM glucose. These findings showed that glucose biofuel cells can be further investigated in the development of a self-powered glucose biosensor. To achieve this task, we incorporated a charge pump circuit and a capacitor as the transducer element. By monitoring the capacitor charging frequencies, which are influenced by the concentration of the glucose analyte in the biofuel cell, a linear dynamic range of 3 - 20 mM glucose is observed. The operational stability of SPGS was monitored over a period of 53 days and was found to be stable with 4.17% (least) and 9.09% (peak) drop in sensor performance under continuous discharge in 20 mM and 3 mM glucose, respectively. Thereby not requiring recalibration during the 53-day period and retaining over 90% of the initial activity compared to the Continuous Glucose Monitors (CGM) that requires calibration every 12 hours. The system was further characterized by testing the performance of the system at various temperature, pH and amidst various interfering and competing chemical species such as uric acid, ascorbic acid, fructose, maltose and galactose. To amplify the system?s performance further, a step-up DC converter circuit was interfaced with the charge pump circuit. The output from the charge pump circuit provided a necessary 1.4 V trigger to drive the step-up DC converter circuit. The system exhibited a 3.7-fold increase in sensitivity while powering a digital glucometer device. These results demonstrate that SPGSs can simultaneously generate bioelectricity to power ultra-low powered bioelectronic devices and sense glucose. To the best of our knowledge, practical power was generated to power a glucometer and the sensing characteristics are an improvement over the existing state of art. Such a practical glucose sensing system powered by a single enzymatic glucose biofuel cell overcomes the drawbacks of present glucose monitors by eliminating the battery, device bulkiness and the frequent need for recalibration
Cost-Effective Hierarchical Cobalt Nanostructured Laser-Induced Graphene for Enhanced Uric Acid Detection
No full textThis study presents an innovative, cost-effective strategy to develop a flexible, enzyme-free biosensor for the sensitive detection of uric acid (UA). Utilizing electrochemically modified cobalt nanostructured on laser-induced graphene electrodes (CoNCs/LIG), this approach surpasses traditional noble metal-based electrocatalysts in sensitivity and affordability. The one-step electrochemical modification method is efficient and straightforward, enabling the uniform deposition of hierarchical flower-like cobalt nanostructures. These structures synergistically enhance the performance of the LIG, resulting in a broad detection range of 5 to 700 µM with a sensitivity of 6.75 µA µM-¹ cm-² and a low detection limit of 3.66 µM for UA. The morphology and elemental composition of the CoNCs/LIG electrodes are characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Beyond sensitivity, the sensor exhibited excellent selectivity, reliably resisting interference from competing biologically species such as ascorbic acid, dopamine, glycine, and glucose. Clinical utility is demonstrated in serum and artificial urine samples, achieving recovery rates ranging from (102.47%-104.46%). This work highlights the exceptional electrocatalytic efficiency of CoNCs/LIG-based flexible biosensors, offering a highly sensitive, selective, and cost-effective platform for UA detection, with promising applications in clinical diagnostics and health monitoring
Molecular Imprinting and Nanomaterial Synergy for Lactate Detection
No full textMolecularly imprinted polymer (MIP)-based electrochemical sensors have emerged as promising non-enzymatic platforms for the selective and stable detection of clinically and environmentally relevant biomarkers. This review provides a critical, comprehensive analysis of recent advances in MIP-based lactate sensing, with particular emphasis on hybrid systems that integrate conductive nanomaterials including gold and silver nanoparticles, laser-induced graphene, and reduced graphene oxide. These synergistic combinations leverage enhanced surface area, electrical conductivity, and molecular recognition to improve sensor sensitivity, selectivity, and long-term operational stability. Key fabrication strategies, such as electropolymerization, green nanomaterial synthesis, and surface imprinting, are critically examined for their roles in optimizing imprinting sensitivity and electron transfer efficiency. Application areas span real-time lactate monitoring in wearable health devices to environmental surveillance in complex matrices. Despite significant progress, challenges related to reproducibility, template removal efficiency, fouling resistance, and scalable manufacturing persist. The review concludes by outlining future directions, including integration into flexible and paper-based platforms, and the development of smart, implantable systems. With continued innovation, MIP-based lactate sensors are poised to become essential components in next-generation point-of-care diagnostics and environmental monitoring technologies
Storage stability of electrospun pure gelatin stabilized with EDC/Sulfo‐NHS
No full textWith the rapid development of biomimetic polymers for cell‐based assays and tissue engineering, crosslinking electrospun nanofibrous biopolymer constructs is of great importance for achieving sustainable and efficient three‐dimensional scaffold constructs. Uncrosslinked electrospun gelatin nanofibrous constructs immediately and completely dissolved in aqueous solutions due to their aqueous solubility and poor storage stability. Here, a novel and versatile approach for the fabrication and crosslinking of electrospun gelatin construct with tunable porosity and high aspect ratio nanofibers is presented. Uncrosslinked electrospun gelatin/genipin nanofibrous and pure gelatin nanofibrous constructs exhibited smooth surfaces that were well‐defined, with a diameter in the range of 448 ± 364 nm and 257 ± 57 nm, respectively. Dehydrothermal, genipin‐EDC/Sulfo‐NHS, and EDC/Sulfo‐NHS crosslinking approaches were examined to achieve insoluble gelatin nanofibrous constructs that were suitable for cell‐based assays. Mechanical characterization demonstrated that the pure gelatin nanofibrous construct crosslinked via EDC/Sulfo‐NHS exhibited an increased mechanical strength and stiffness and showed no dissolution in aqueous solutions and retained its fiber morphology. An excellent 1 month storage stability was demonstrated at 22, 4, −20, and −80°C (dehydrated) and at 4°C (hydrated). The as‐crosslinked gelatin nanofibrous construct was highly biocompatible (90% cell viability), as demonstrated by the promoted proliferation of PC12 cells.Maryland Industrial Partnerships, Grant/Award Number: 6002https://onlinelibrary.wiley.com/doi/abs/10.1002/bip.2323
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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