As a next-generation electrocatalytic material, Ru–W nanocluster-modified g-C3N4 was synthesized using a straightforward monomer-complexation route from Ru-substituted phosphotungstate, for efficient hydrogen evolution reaction.

The requirement for wearable sensing technology has gained momentum, due to its ability for real-time acquisition of physiological data. To broaden access to personalized healthcare, non-invasive monitoring of metabolites is of particular interest. This manuscript describes our work on subdermal wearable patches, designed for ambulatory measurements of levels of glucose and lactate. One key finding of this research is the onset of biofouling after 24 hours of wear. This research confirms the efficacy of subdermal wearable patches for real-time metabolite monitoring, thus playing a pivotal role in the advancement of healthcare monitoring.

Development of wearable sensing devices for minimally invasive and real time monitoring of physiological information in ambulatory conditions.

Interdigitated electrodes (IDEs) enable electrochemical signal enhancement through repeated reduction and oxidation of the analyte molecule. Porosity on these electrodes is often used to lower the impedance background. However, their high capacitive current and signal interferences with oxygen reduction limit electrochemical detection ability. We present utilization of alkanethiol modification on nanoporous gold (NPG) electrodes to lower their background capacitance and chemically passivate them from interferences due to oxygen reduction, while maintaining their fast electron transfer rates, as validated by lower separation between anodic and cathodic peaks (ΔE) and lower charge transfer resistance (Rct) values in comparison to planar gold electrodes. Redox amplification based on this modification enables sensitive detection of various small molecules, including pyocyanin, p-aminophenol and selective detection of dopamine in the presence of ascorbic acid. Alkane thiol NPG arrays are applied as a multiplexed sensor testbed within a well plate to screen binding of various peptide receptors to the SARS COV2 S-protein by using a sandwich assay for conversion of PAPP (4-aminophenyl phosphate) to PAP (p-aminophenol), by the action of AP (alkaline phosphatase), which is validated against optical ELISA screens of the peptides. Such arrays are especially of interest in small volume analytical settings with complex samples, wherein optical methods are unsuitable.

Phosphorylated Tau proteins are promising biomarkers for the diagnosis and prognosis of Alzheimer's disease. This study presents a novel voltametric sensor using a vanadium MXene polydopamine (VxPDA) redox active composite and a Tau-441-specific polyaniline molecularly imprinted polymer (PANI MIP) for the sensitive detection of Tau-441 in interstitial fluid (ISF) and plasma. The VxPDA/PANI MIP sensor demonstrates a broad detection range of 5 fg/mL to 5 ng/mL (122 aM/L to 122 pM/L) in ISF without the use of redox mediators, with a lower limit of detection (LOD) of 2.3 fg/mL (60 aM/L). Furthermore, a handheld device utilizing this technology successfully detects Tau-441 in artificial serum with high sensitivity (5 fg/mL to 150 fg/mL (122 aM/L to 366 aM/L)) and specificity within a clinically relevant range. The rapid detection time (∼32 min) and low cost (∼£20/device) of this sensor highlight its potential for minimally invasive, early AD diagnosis in clinical settings. This advancement aims to facilitate a transition away from invasive cerebrospinal fluid (CSF)-based diagnostic techniques for AD.

Over the last decade, a significant paradigm shift has been observed towards leveraging less invasive biological fluids—such as skin interstitial fluid (ISF), sweat, tears, and saliva—for health monitoring. This evolution seeks to transcend traditional, invasive blood-based methods, offering a more accessible approach to health monitoring for non-specialized personnel. Skin ISF, with its profound resemblance to blood, emerges as a pivotal medium for the real-time, minimally invasive tracking of a broad spectrum of biomarkers, thus becoming an invaluable asset for correlating with blood-based data. Our exploration delves deeply into the development of wearable molecular biosensors, spotlighting dermal sensors for their pivotal roles across both clinical and everyday health monitoring scenarios and underscoring their contributions to the holistic One Health initiative. In bringing forward the myriad challenges that permeate this field, we also project future directions, notably the potential of skin ISF as a promising candidate for continuous health tracking.Moreover, this paper aims to catalyse further exploration and innovation by presenting a curated selection of seminal technological advancements. Amidst the saturated landscape of analytical literature on translational challenges, our approach distinctly seeks to highlight recent developments. In attracting a wider spectrum of research groups to this versatile domain, we endeavour to broaden the collective understanding of its trajectory and potential, mapping the evolution of wearable biosensor technology. This strategy not only illuminates the transformative impact of wearable biosensors in reshaping health diagnostics and personalized medicine but also fosters increased participation and progress within the field. Distinct from recent manuscripts in this domain, our review serves as a distillation of key concepts, elucidating pivotal papers that mark the latest advancements in wearable sensors. Through presenting a curated collection of landmark studies and offering our perspectives on the challenges and forward paths, this paper seeks to guide new entrants in the area. We delineate a division between wearable epidermal and subdermal sensors—focusing on the latter as the future frontier—thereby establishing a unique discourse within the ongoing narrative on wearable sensing technologies.

Here, a dual functional Nb2CTx@Pt nanocomposite has been synthesized by in situ reduc-tion method. The Pt loading in the composite has been optimized to get minimum over -potential (141 mV at 10 mA/cm2) for hydrogen evolution reaction (HER) along with a promising Tafel slope of 46.3 mV/dec, while Pt/C shows an overpotential and Tafel slope of 104 mV and 32.4 mV/dec, respectively. The Pt mass activity for Nb2CTx@Pt3.8 composite at 100 mV overpotential was 3.44 A g-1 while the Pt mass activity for conventional Pt/C was 0.7 A g-1, which shows that the activity of Nb2CTx@Pt3.8 composite is approximately 5 times higher than Pt/C. In addition, the catalyst was found to be stable for continuous 500 cycles without any binder molecules. The oxygen reduction reaction (ORR) capability of the material was also evaluated and found that the catalyst exhibited a current density of -4.28 mA/cm2 in the diffusion limiting region in comparison with the current density of -5.82 mA/cm2 for Pt/C at 2600 revolutions per minute (RPM). The Pt mass activity of Nb2-CTX@Pt3.8 composite for ORR is approximately 10 times higher than Pt/C. The Nb2CTX@-Pt3.8 composite was able to reduce O2 completely using the 4-electron pathway with very little peroxide production. From these results, the dual functionality of the Nb2CTX@Pt3.8 composite for both HER and ORR has been established.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Detection of hydrogen peroxide (H2O2) from cell cultures is important for monitoring different diseases. Here, g-C3N4 (gCN) was incorporated into well-defined clusters of RuW (RuW-gCN) through monomer complexation of Ru-substituted phosphotungstate and melamine for electrochemical detection of H2O2. RuW-gCN exhibited enhanced electrochemical sensing properties in comparison to its constituents due to the synergic effects between RuW and gCN. The characterization of RuW-gCN revealed successful complexation to form the composite in addition to the presence of a layered structure of gCN. The electrochemical sensor made of RuW-gCN was able to detect H2O2 with a detection limit of 46 nM in the linear ranges from 100 nM to 50 μM and from 50 μM to 1 mM. The developed sensor was employed for the selective detection of H2O2 in the presence of analytes like ascorbic acid (AA), dopamine, and glucose in addition to being stable even after a week of storage at room temperature. It has also been verified for real sample application by detecting H2O2 produced by cancer cells as a result of an AA trigger.

Neurotransmitters are small chemical signaling molecules crucial for the proper function of the nervous system. The dysregulation of neurotransmitters results in several mental disorders like Parkinson's and Alzheimer's diseases, schizophrenia, and conditions such as depression and addiction. These signaling molecules are present at low concentrations, and obtaining information about these molecules' levels is vital. Moreover, neurotransmitter monitoring in the nervous system remains challenging due to its low concentrations and rapid response. Electrochemical detection continues to garner significant attention as an attractive technique due to its facile nature, high sensitivity, and cost-effectiveness. The electroactive materials of electrochemical sensors are at the heart of this sensing technology. Although multiple nanomaterials have been explored as active components in electrochemical sensors for detecting neurotransmitters, MXenes are gaining attention in the electrochemical sensing of neurotransmitters. This review aims to discuss the use of MXenes and their composites for the electrochemical detection of neurotransmitters, describe the various MXene composites based on the nature of the composite viz pristine and chemical functionalized, carbon nanomaterial, polymer, metal nanoparticle, and transition metal dichalcogenide (TMDC) composites, and define the future directions in leveraging the properties of MXene composites for early-stage electrochemical detection of neurological diseases originating from an imbalance in neurotransmitters.

Here, Nb2CTx@MoS2 composites have been synthesized and their catalytic activity towards the reduction of organic dyes was evaluated. The Nb2CTx@MoS2 composite has been synthesized in different ratios (25, 50, and 75%) and it was found that Nb2CTx@50MoS2 (50% MoS2) was the best composite, as it was able to achieve complete reduction of methylene blue and methyl orange within 3 and 4 min, with rate constant of 0.55305 min−1, and 0.371 min−1, respectively. In addition, the catalyst was able to retain 86% of activity even after the 5 consecutive cycles.

Fatal diseases like cancers, neurodegenerative, cardiac, pulmonary, and kidney diseases can be treated effectively if they are diagnosed at early stages. The diagnosis of these diseases can be carried out effectively using biomarkers that are released into the blood stream, sweat, and saliva due to various physiological processes. If these biomarkers can be detected when their concentrations in the body start to exhibit abnormal trends, processes to mitigate these abnormalities can be adopted. Additionally, the effect of treatment methodologies and the resultant prognosis of the disease can be analyzed if the levels of biomarkers can be correlated to the treatment methodology adopted. For carrying out the early-stage diagnosis and prognosis, sensors incorporating sensitive detection elements are required. Nb MXenes are a subclass of 2D transition metal carbides that have been receiving attention in this aspect. These MXenes possess superior properties like excellent electronic conductivity, electrochemical and photothermal stability, and biocompatibility that make them valuable as sensing elements in a wide variety of sensor paradigms like electrochemical, optical, electrical, and electronic sensors. This review discusses the synthesis of Nb MXenes, advantages of using Nb MXenes over other MXenes, and reviews the use of these materials as detection elements in sensors that were used to detect biomarkers holding diagnostic and prognostic significance. The review concludes with future perspectives in this area, which discusses avenues for development of Nb MXene based diagnostic and prognostics.

A heterostructure of MXene and MoS2 (Nb2CTx@MoS2) was synthesized and used for the ultrasensitive and selective detection of dopamine (DA). The composite was synthesized using a facile hydrothermal strategy and it was used to modify the carbon cloth (CC). The best composition of the material for DA detection was optimized by varying the content of MoS2 from 6.25 to 25 % while keeping the amount of Nb2CTx constant. From the electrochemical analysis, it was found that Nb2CTx@12.5MoS2 showed the best sensing characteristics owing to the optimum interaction between MoS2 and Nb2CTx. The Nb2CTx@MoS2 modified CC was able to detect DA linearly from 1 fM to 100 mu M with a limit of detection (LOD) of 0.23 fM. The LOD of 0.23 fM is the lowest for DA detection in comparison with other MXene-based composites to the best of our knowledge. The developed sensor exhibited promising selectivity for determination of DA in presence of other interferents like uric acid and ascorbic acid. In addition, the developed sensor showed good repeatability, cyclic and storage stability, which shows the potential of this composite for developing flexible electrochemical sensors for the ultrasensitive and selective determination of DA.

The determination of neurotransmitters and adrenoreceptor drugs is highly essential due to their specific functions in the human body. In this work, the determination of carvedilol (CAR) and dopamine (DA) was carried out using carbon cloth (CC), which was modified using a facile strategy of drop-casting dimethyl sulfoxide (DMSO). This induced the formation of functional groups without any loss in the structural integrity of CC. The DMSO modified CC (CC-DMSO) was used for the detection of CAR in the range of 1 nM to 10 μM with a limit of detection (LOD) of 120 pM. Similarly, the CC-DMSO was able to detect DA in the range of 10 pM to 10 μM with a highly promising LOD of 0.3 pM. A bending test was also carried out on the electrode and it could be seen that only a negligible variation in sensing capability was observed when the electrode was in the bent form. In addition, the detection of CAR and DA was also carried out in real samples such as human serum. This study reveals that this modification strategy can serve as a versatile and flexible sensing platform for the detection of CAR and DA together in real world medical scenarios.

Cobalt is an ideal material for application in energy storage devices owing to its superior stability and redox activity. However, there has been a rise in demand for cobalt-based energy storage devices, which cannot be satisfied because of cost considerations. To balance demand and cost, cost-effective alternatives like copper can be envisaged. The present work underlines the potential of nickel-copper selenide as a suitable replacement for nickel-cobalt selenide electrodes for hybrid supercapacitor (HSCs) application. In half cell testing, NiCuSe and NiCoSe deliver a specific capacity of 127.2 mAh g(-1) and 177.2 mAh g(-1), respectively, at a current density of 3 A g(-1). NiCuSe exhibits more stable charge storage than NiCoSe at high current densities owing to its superior conductivity. Aqueous HSCs, NiCuSe// modified activated carbon (MAC) and NiCoSe//MAC deliver an energy density and power density of 26.56 Wh kg(-1) at 2.732 kW kg(-1) and 28.78 Wh kg(-1) and 2.571 kW kg(-1), respectively. NiCuSe//MAC shows superior rate capability, and both devices exhibit superior cycle life for 12,000 cycles.

The electrochemical detection of dopamine (DA) is of ultimate importance in the early-stage diagnosis of Parkinson's and Alzheimer's diseases. In this work, we report the development of a facile amination technique of Nb2CTx MXenes for the electrochemical sensing of DA. The amination was confirmed using fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy the structural changes due to the amination process were confirmed using X-Ray diffractograms. The modified MXenes were used to modify carbon cloth electrodes, which were then applied to the electrochemical detection of DA. The developed sensor was able to detect dopamine linearly in the range 1 nM–100 μM and a limit of detection of (LOD) of 300 pM was achieved. The modified electrode was found to have a selective response to DA in the presence of other interferents in addition to being reproducible and stable. The modified electrode was also used for the detection of DA in serum samples with little difference in the sensing characteristics in phosphate buffer. This work presents a novel amination route for the surface functionalization of Nb2CTx and opens new avenues for applications of surface functionalized Nb-MXenes in electrochemical detection of neurotransmitters.

We report on the catalytic activity of Nb 4 C 3 T x based composites towards the catalytic reduction of nitro compounds and organic dyes for the first time.

Since the first report of MXenes in 2011, the application prospects of this material have expanded to several fields ranging from energy storage and conversion, optics, electronics, and sensors to a device level integration in these areas. The use of MXenes in sensing devices had led to better conductivity, larger surface areas for enhanced detection of various analytes. In addition, a wide range of functionalization and compositing of these materials has also improved the sensing characteristics. The central objective of this review is to highlight the application of MXenes in wearable sensing devices. This review attempts to detail the reports where MXenes have been used in wearable sensing devices so that the future prospect of the application of these materials can be analyzed. This will help in developing innovative devices that use MXenes and help towards advancing the application of such devices in real life scenarios.

The detection of hydrogen peroxide (H 2 O 2 ) holds significance in the healthcare sector. In this work, carbon cloth (CC) was modified with a novel composite of Nb 4 C 3 T x MXene and Prussian blue (PB) for the electrochemical detection of H 2 O 2 . The method of preparation followed was simple drop casting of Nb 4 C 3 T x on CC followed by the electrochemical deposition of PB using chronoamperometry (CA) at 0.7 V. It was found that uniform coverage of PB occurred on the underlying Nb 4 C 3 T x surface. The electrochemical deposition time was optimized (by varying the deposition time as 240 s, 360 s, 480 s, and 600 s) and the material obtained after 480 s deposition was found to produce better sensing characteristics towards the detection of H 2 O 2 . The Nb 4 C 3 T x /PB 480 modified CC was able to detect H 2 O 2 linearly in the range of 500 nM to 100 µM with an LOD of 190 nM. The sensor was also able to showcase good selectivity to H 2 O 2 even in the presence of interfering molecules like dopamine, ascorbic acid, uric acid, and sodium chloride. In addition, the material exhibited good storage stability, which was seen by the retention of 97% of activity even after a storage time of 1 week. This material can be applied towards the sensing of H 2 O 2 in physiologically relevant media since pH of the buffer used in the work matches the pH of our physiological conditions.