Optimization of biogenic synthesis of biocompatible platinum nanoparticles with catalytic, enzyme mimetic and antioxidant activities

Abstract

Owing to platinum's nobility, catalytic potential and vast range of possible biomedical applications, synthesis of platinum nanoparticles is attracting the attention of scientists worldwide. Though the plant mediated methods are simple and easy, they require fine tuning of reaction parameters so as to synthesize nanoparticles of desired properties. The present study aimed to optimize the food waste almond skin extract mediated synthesis of biocompatible platinum nanoparticles with catalytic, enzyme-mimicking, and antioxidant activities. The optimization of reaction parameters indicated that 10 mM of precursor in 2:1 ratio with extract, pH 9, and incubation at 90 °C for 14 min were the optimum parameters. The characterization using various spectroscopic and imaging techniques indicated that platinum nanoparticles were 6–8 nm in size, face centered cubic, irregularly shaped, and negatively charged. When tested for catalytic activity, platinum nanoparticles catalyzed highest of 90.39% reduction of 4-nitrophenol in 16 min. The reaction containing 30 ppm of 4-nitrophenol, catalyst dosage of 0.6 mg/mL, and pH 10 followed pseudo-first order kinetics. Furthermore, platinum nanoparticles were found to possess amylase-mimicking activity of 3.83 μg/mL/min. In addition, platinum nanoparticles showed strong antioxidant activities in a dose-dependent manner signifying them as potentially good antioxidant agents. When tested for cytotoxicity, peripheral blood mononuclear cells were found unaffected when treated with relatively high concentrations (100 μg/mL) of PtNP demonstrating good biocompatibility. Thus, the present study successfully demonstrated the use of almond skin extract as food waste for the biogenic synthesis of biocompatible platinum nanoparticles with biological activities.