Direct Electron Transfer based Microfluidic Glucose Biofuel cell with CO2 Laser ablated Bioelectrodes and Microchannel

Benchmarking Power Generation From Multiple Wastewater Electrolytes in Microbial Fuel Cells With 3D Printed Disk-Electrodes

Microbial Fuel Cells (MFCs) have recently gained attention, as they are inexpensive, green in nature, and sustainable. As per the report, by Allied Market Research the global market size of MFCs will increase from $ 264.8 million in 2021 to $ 452.2 million in 2030, growing at a CAGR of 4.5%. The present work is a comparative study of various types of electrolytes that can be used in MFCs. The working electrodes were printed using conducting graphene-based Polylactic Acid (PLA) filaments with the help of a 3D printer under the principle of the fused deposition method. Simulated electrolytes and natural environmental microbial electrolytes were used here. Also, electrolytes of pure E. coli culture were studied. Lake water reported the highest power density of 8.259 mW/cm2 while Stale E. Coli reported the lowest around 0.184 mW/cm2. The study comprehensively lists potential wastewaters that can fuel the MFCs. With the pioneering of various comparative studies of electrolytes, one can insight into the recruitment of electrolytes with high-performance benchmarks for miniaturized energy storage and other microelectronics applications.

Microfluidic Device Integrated With PDMS Microchannel and Unmodified ITO Glass Electrodes for Highly Sensitive, Specific, and Point-of-Care Detection of Copper and Mercury

This work delves upon developing a two-layer plasma-bonded microfluidic device with a microchannel layer and electrodes for electroanalytical detection of heavy metal ions. The three-electrode system was realized on an ITO-glass slide by suitably etching the ITO layer with the help of CO2 laser. The microchannel layer was fabricated using a PDMS soft-lithography method wherein the mold created by maskless lithography. The optimized dimensions opted to develop a microfluidic device with length of 20 mm, width of 0.5 mm and gap of 1 mm. The device, with bare unmodified ITO electrodes, was tested to detect Cu and Hg by a portable potentiostat connected with a smartphone. The analytes were introduced in the microfluidic device with a peristaltic pump at an optimal flow rate of [Formula: see text]/min. The device exhibited sensitive electro-catalytic sensing of both the metals by achieving an oxidation peak at -0.4 V and 0.1 V for Cu and Hg respectively. Furthermore, square wave voltammetry (SWV) approach was used to analyze the scan rate effect and concentration effect. The device also used to simultaneously detect both the analytes. During simultaneous sensing of Hg and Cu, the linear range was observed between [Formula: see text] to [Formula: see text], the limit of detection (LOD) was found to be [Formula: see text] and [Formula: see text] for Cu and Hg respectively. Further, no interference with other co-existing metal ions was found manifesting the specificity of the device to Cu and Hg. Finally, the device was successfully tested with real samples like tap water, lake water, and serum with remarkable recovery percentages. Such portable devices pave way for detecting various heavy metal ions in a point-of-care environment. The developed device can also be used for detection of other heavy metals like cadmium, lead, zinc etc., by modifying the working electrode with the various nanocomposites.

Laser-inducedin situsynthesis of nano-composite Co-Co3O4-rGO on paper: miniaturized biosensor for alkaline phosphatase detection

Recent progress in thein situsynthesise of various nanomaterials has gained tremendous interest and wide applications in various fields. For the first time to the best of our knowledge, this work reports a methodology of ultra-fastin situsynthesis of cobalt-cobalt oxide-reduced graphene oxide (Co-Co₃O₄-rGO (CC-rGO)) composite by laser ablation. The photothermal reduction technique was leveraged to develop the CC-rGO. For this, a low-cost 450 nm blue diode laser was irradiated onto a grade 1 filter paper in the presence of cobalt ions readily patterns the carbon matrix of paper to the composite material. Moreover, the variation of cobalt concentrations from 0.1-0.5 M led to structural and morphological changes. Standard techniques were adopted for thorough characterizations of developed sensor material for conductivity analysis, specific surface area, crystal-structural information, surface morphology, and chemical composition. The observed results were highly promoting towards the electrochemical sensing applications. Further, the developed sensor was found to be highly selective toward detecting a vital bio analyte alkaline phosphatase (ALP). The sensors performance was highly significant in the linear range of 10-800 mU l^-1with a detection limit of 10.13 mU l^-1. The sensors applicability was further validated in actual human serum samples via a recovery-based approach. In the future, the developedin situmaterial methodology can begin a rapid composite material synthesis at a larger scale.

Laser induced graphanized microfluidic devices

With the advent of cyber-physical system-based automation and intelligence, the development of flexible and wearable devices has dramatically enhanced. Evidently, this has led to the thrust to realize standalone and sufficiently-self-powered miniaturized devices for a variety of sensing and monitoring applications. To this end, a range of aspects needs to be carefully and synergistically optimized. These include the choice of material, micro-reservoir to suitably place the analytes, integrable electrodes, detection mechanism, microprocessor/microcontroller architecture, signal-processing, software, etc. In this context, several researchers are working toward developing novel flexible devices having a micro-reservoir, both in flow-through and stationary phases, integrated with graphanized zones created by simple benchtop lasers. Various substrates, like different kinds of cloths, papers, and polymers, have been harnessed to develop laser-ablated graphene regions along with a micro-reservoir to aptly place various analytes to be sensed/monitored. Likewise, similar substrates have been utilized for energy harvesting by fuel cell or solar routes and supercapacitor-based energy storage. Overall, realization of a prototype is envisioned by integrating various sub-systems, including sensory, energy harvesting, energy storage, and IoT sub-systems, on a single mini-platform. In this work, the diversified work toward developing such prototypes will be showcased and current and future commercialization potential will be projected.

Compared EC-AFM Analysis of Laser-Induced Graphene and Graphite Electrodes in Sulfuric Acid Electrolyte

Flexible and economic sensor devices are the focus of increasing interest for their potential and wide applications in medicine, food analysis, pollution, water quality, etc. In these areas, the possibility of using stable, reproducible, and pocket devices can simplify the acquisition of data. Among recent prototypes, sensors based on laser-induced graphene (LIGE) on Kapton represent a feasible choice. In particular, LIGE devices are also exploited as electrodes for sensing in liquids. Despite a characterization with electrochemical (EC) methods in the literature, a closer comparison with traditional graphite electrodes is still missing. In this study, we combine atomic force microscopy with an EC cell (EC-AFM) to study, in situ, electrode oxidation reactions when LIGE or other graphite samples are used as anodes inside an acid electrolyte. This investigation shows the quality and performance of the LIGE electrode with respect to other samples. Finally, an ex situ Raman spectroscopy analysis allows a detailed chemical analysis of the employed electrodes.