Green synthesis of silver nanoparticles from deoiled brown algal extract via Box-Behnken based design and their antimicrobial and sensing properties

Abstract

Abstract The aim of this work was to acquire even and sphere-shaped silver nanoparticles (AgNPs) using statistical design of experiment. AgNPs were produced by green synthesis method using deoiled Saccharina japonica powder obtained after supercritical carbon dioxide (Sc-CO2) extraction. Based on the Box-Behnken design, three variables influencing the size of AgNPs produced were identified as silver nitrate (AgNO3) concentration, temperature, and reaction time. Optimum conditions were determined using response surface methodology for synthesis of AgNPs. We found that increasing reaction time at low concentration of AgNO3 resulted in smaller particle size, and conversely increasing reaction time at high concentration of AgNO3 resulted in bigger particles. The obtained AgNPs were characterized by transmission electron microscopy, energy dispersive X-ray, X-ray diffraction analysis, and ultraviolet-visible and Fourier transform infrared spectroscopy techniques for particle size, distribution, aggregation, and anisotropy. The optimum operating conditions are 1 mm of AgNO3, 40°C, and 45 min with the smallest AgNPs size being 14.77 nm. The optimized AgNPs showed good antimicrobial activity and excellent sensing behavior towards hydrogen peroxide. The polyphenols present in aqueous AgNPs were evaluated by high-pressure liquid chromatography, which revealed the existence of chlorogenic acid and rutin.