The development of affordable and compact noninvasive point-of-care (POC) dopamine biosensors for the next generation is currently a major and challenging problem. In this context, a highly sensitive, selective, and low-cost sensing probe is developed by a simple one-step laser-scribing process of plastic waste. A flexible POC device is developed as a prototype and shows a highly specific response to dopamine in the real sample (urine) as low as 100 pmol/L in a broad linear range of 10−10–10−4 mol/L. The 3D topological feature, carrier kinetics, and surface chemistry are found to improve with the formation of high-density metal-embedded graphene-foam composite driven by laser irradiation on the plastic-waste surface. The development of various kinds of flexible and tunable biosensors by plastic waste is now possible thanks to the success of this simple, but effective, laser-scribing technique, which is capable of modifying the matrix’s electronic and chemical composition.

Objective: This study was undertaken to know about the antibacterial and anticancer activity of synthesized zinc oxide (ZnO) nanoparticles (NPs). Methods:The ZnO NPs and different concentration of Ce 3+ (0.05M, 0.10M, and 0.15M)-doped ZnO NPs were synthesized by coprecipitation method. The synthesized nanoparticles were analyzed by X-ray diffraction (XRD) and HRSEM. The antibacterial studies were performed against a set of bacterial strains as Gram-positive bacteria (Streptococcus aureus and Streptococcus pneumonia) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Klebsiella pneumonia, and Shigella dysenteriae) bacteria. The cytotoxic effect of ZnO and Ce-doped ZnO was analyzed in cultured (A549) human lung cancer cell line. Result:The XRD studies showed the wurtzite structure of nanoparticles. HRSEM analysis showed the spherical shape of ZnO and Ce-doped ZnO. The