Experimental investigation of performance tailoring of the multifunctional sensor using transition metal (Fe) doped ZnO nanorods synthesized via a facile solution-based method.

A systematic interpretation of the undoped and Fe doped ZnO based multifunctional sensor developed employing economic and facile low-temperature hydrothermal method is reported. The tailoring of the performance improvement of the sensor was deliberately carried out using varied concentration (1, 3 and 5 Wt%) of Fe dopant in ZnO nanorods. The structural and morphological analysis reveal the undisturbed ZnO hexagonal wurtzite structure formation and 1D morphology grown even when the dopant is added. The optical property study evidences a decreased bandgap (3.10 eV) and decreased defects of 5 Wt% of Fe dopant in ZnO nanorods based sensor compared to the undoped one. The electrical process transpiring in the tailored multifunctional sensor is investigated using photoconductivity and impedance analysis elucidates proper construction of p-n junction between the piezoelectric n-type active layer (undoped and Fe doped ZnO nanorods) and p-type PEDOT:PSS ((poly(3,4-ethylene dioxythiophene) polystyrene sulfonate)) and reduced internal resistance of 5 Wt% of Fe dopant in ZnO nanorods based sensor (131.97 Ω) respectively. The investigation on the experimental piezoelectric acceleration and gas sensing validation and the performance measurement were interpreted using test systems. A revamped output voltage of 3.71 V for 1 g input acceleration and a comprehensive sensitivity of 7.17 V g-1was achieved for the 5 Wt% of Fe dopant in ZnO nanorods based sensor sensor. Similarly, an upgraded sensitivity of 2.04 and 6.75 for 5 Wt% of Fe dopant in ZnO nanorods based sensor was obtained when exposed to 10 ppm of target gases namely CO and CH4respectively at room temperature. Appending to this, acceptable stability of the sensor for both the sensing (acceleration and gas) was also attained manifesting its prospective application in multifunctional based systems like sewage systems.

Novel ruthenium-doped vanadium carbide/polymeric nanohybrid sensor for acetaminophen drug detection in human blood.

The use of advanced electroactive catalysts enhances the performance of electrochemical biosensors in real-time biomonitoring and has received much attention owing to its excellent physicochemical and electrochemical possessions. In this work, a novel biosensor was developed based on the electrocatalytic activity of functionalized vanadium carbide (VC) material, including VC@ruthenium (Ru), VC@Ru-polyaniline nanoparticles (VC@Ru-PANI-NPs) as non-enzymatic nanocarriers for the fabrication of modified screen-printed electrode (SPE) to detect acetaminophen in human blood. As-prepared materials were characterized using SEM, TEM, XRD, and XPS techniques. Biosensing was carried out using cyclic voltammetry and differential pulse voltammetry techniques and has revealed imperative electrocatalytic activity. A quasi-reversible redox method of the over-potential of acetaminophen increased considerably compared with that at the modified electrode and the bare SPE. The excellent electrocatalytic behaviour of VC@Ru-PANI-NPs/SPE is attributed to its distinctive chemical and physical properties, including rapid electron transfer, striking á´«-á´« interface, and strong adsorptive capability. This electrochemical biosensor exhibits a detection limit of 0.024 µM, in a linear range of 0.1-382.72 µM with a reproducibility of 2.45 % relative standard deviation, and a good recovery from 96.69 % to 105.59 %, the acquired results ensure a better performance compared with previous reports. The enriched electrocatalytic activity of this developed biosensor is mainly credited to its high surface area, better electrical conductivity, synergistic effect, and abundant electroactive sites. The real-world utility of the VC@Ru-PANI-NPs/SPE-based sensor was ensured via the investigation of biomonitoring of acetaminophen in human blood samples with satisfactory recoveries.

Nickel Cobalt Telluride Nanorods for Sensing the Hydrogen Peroxide in Living Cells.

In this study, we report about the preparation of nickel cobalt telluride nanorods (NiCoTe NRs) by the hydrothermal method using ascorbic acid and cetyltrimethylammonium bromide as reducing agents. The NiCoTe NRs (NCT 1 NRs) were characterized through use of different methods. The nonlinear optical measurements were carried out using Z-scan techniques. The results give the nonlinear absorption that arises from the combined two photon absorption and free carrier absorption. NCT 1 has an excellent electrocatalytic activity toward hydrogen peroxide with a sensitivity of 3464 µA mM-1 cm-2, a wide linear range of 0.002-1835 µM, and the lower detection limit of 0.02 µM, and the prepared electrode was strong in sensing in vivo H2O2 free from raw 264.7 cells. Therefore, the binary transition metal chalcogenide based nanostructures have promising potential in live cell biosensing applications.