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Biological synthesis of gold nanoparticles (AuNPs) is gaining attention of researchers because of their varieties of biomedical applications. This study reported the novel, eco-friendly synthesis of AuNPs using dried fruit extract of Capsicum annum (C. annum). Biosynthesized gold nanoparticles (Ca-AuNPs) showed UV absorption peak at 540 nm and were found to be stable for up to three months. The nanoparticles were further characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FT-IR), Energy Dispersive X-ray Analysis (EDAX) and X-ray diffraction (XRD) analysis. The nanoparticles were spherical in shape with size range of 20–30 nm and zeta potential study confirmed the surface charge of -26.5 mV. The Ca-AuNPs were tested for anti-angiogenic activity using Chorioallantoic membrane (CAM) assay that implied a significant anti-angiogenic efficiency of Ca-AuNPs at 100 µg/mL concentration. The antioxidant activity of Ca-AuNPs studied by 2,2- diphenyl-1-picrylhydrazyl (DPPH) assay was found to be significant with 86.0% radical scavenging activity. These nanoparticles also revealed anti-inflammatory activity at concentration range 100–1200 µg/mL with IC-50 value619.4 µg/mL. The present study includes synthesis of Ca-AuNPs by using phytoconstituents of plant material as reducing agents to efficiently exploit the biomedical applications of the nanoparticles.

Resistive-switching-based memory devices meet most of the requirements for use in next-generation information and communication technology applications, including standalone memory devices, neuromorphic hardware, and embedded sensing devices with on-chip storage, due to their low cost, excellent memory retention, compatibility with 3D integration, in-memory computing capabilities, and ease of fabrication. Electrochemical synthesis is the most widespread technique for the fabrication of state-of-the-art memory devices. The present review article summarizes the electrochemical approaches that have been proposed for the fabrication of switching, memristor, and memristive devices for memory storage, neuromorphic computing, and sensing applications, highlighting their various advantages and performance metrics. We also present the challenges and future research directions for this field in the concluding section.

Nanogenerators are the backbone of self-powered systems and they have been explored for application in miniaturized biomedical devices, such as pacemakers. Piezoelectric nanogenerators (PENGs) have several advantages, including their high efficiency, low cost, and facile fabrication processes, which have made them one of the most promising nano power sources for converting mechanical energy into electrical energy. In this study, we review the recent major progress in the field of PENGs. Various approaches, such as morphology tuning, doping, and compositing active materials, which have been explored to improve the efficiency of PENGs, are discussed in depth. Major emphasis is given to material tailoring strategies and PENG fabrication approaches, such as 3D printing, and their applications in the biomedical field. Moreover, hybrid nanogenerators (HNG), which have evolved over the last few years, are discussed. Finally, the current key challenges and future directions in this field are presented.

The massively parallel computing capabilities of the human brain can be mimicked with the help of neuromorphic computing approach and this can be achieved by developing the electronic synaptic device. In the present work, we have synthesized gallium-doped ZnO thin films using a cost-effective hydrothermal method and characterized the thin films using field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. Furthermore, gallium-doped ZnO memristive devices were developed using standard procedure and electrically characterized for the neuromorphic application. In particular, resistive switching and synaptic properties of gallium-doped ZnO thin films were investigated. The bipolar resistive switching with an analog memory like behavior was observed in the developed memristive devices. In the present case, good synaptic properties, endurance, and retention characteristics were observed for 0.5% Ga doped memristive device. Our results suggested that the synaptic weight, potentiation-depression, and symmetric Hebbian learning can be tuned with properly engineering the ZnO memristive device with appropriate gallium doping. The detailed analysis of I-V results suggested that resistive switching is occurred due to Ohmic and Schottky conduction mechanisms. Keywords: Memristive device, Resistive switching, Gallium doped ZnO, Electronic synapse, Potentiation and depression, Hebbian learning