Processing and antibacterial application of biodegradable sponge nano-composite materials of silver nanoparticles and silk sericin

Abstract

This work presents a simple, eco-friendly and rapid method to synthesize silver nanoparticles (AgNPs) incorporated into a new kind of water absorption sponge; i.e. bio-based sponge to become a special material called the biodegradable sponge nano-composite material (BS-NCMs) that has an antibacterial property. In this work, silk sericin (SS) was introduced as a reducing agent to prepare AgNPs and as a base substance to prepare the biodegradable sponge. The synthesis of AgNPs via an ultrasonic technique was found to be shortened. The optimum time for formation of AgNPs was determined to be 30 min by UV–Vis spectroscopy at wavelength 442 nm. TEM and DLS revealed that the synthesized AgNPs were in round shape and the size ranged from 10 to 30 nm depending on the SS concentration. The antibacterial activity of the synthesized AgNPs was quite obvious showing the MIC and MBC against Escherichia coli (E. Coli) and Staphylococcus aureus (S. aureus) at 62.5 and 125 ppm, respectively. Next, BS-NCM of SS and carboxymethyl cellulose (CMC) was prepared by freeze-drying and chemically cross-linked with the incorporation of the synthesized AgNPs. The structures of BS-NCMs revealed the impregnation of AgNPs by FE-SEM with EDX. It also showed good antibacterial property. The inhibition zone diameter of BS-NCMs against S. aureus and E. Coli were found to be 8–10 mm and 10–12 mm, respectively that it depends on the concentration of AgNPs. Effects of crosslinking agent on the water absorption of BS-NCMs showed to lower the degree of water absorption by 2 times as increasing crosslinker 50%.