Synthesis, characterization, and cytotoxicity of starch-encapsulated biogenic silver nanoparticle and its improved anti-bacterial activity

Abstract

The present work reported synthesis, characterization, and biocompatibility of starch encapsulated silver nanoparticles (St-PF-AgNPs) and their antibacterial activity. The synthesis of St-PF-AgNPs involved in two steps: (i) synthesis of the biogenic silver nanoparticles using the fungal extracts (PF-AgNPs); and, (ii) encapsulation of starch in PF-AgNPs (St-PF-AgNPs). The surface plasmon resonance was found at 420 nm for the PF-AgNPs while it was at 260 and 420 nm for the St-PF-AgNPs. FTIR spectrum demonstrated the capping and encapsulation of the fungal extracts and starch in PF-AgNPs and St-PF-AgNPs. The XRD and TEM-EDS confirmed the crystalline nature, spherical-shaped , and polydispersed- PF-AgNPs and St-PF-AgNPs with strong signals of Ag. The St-PF-AgNPs showed a Z-average size of 115.2 d.nm and zeta potential of -17.8 (mV) as indicated by DLS and zeta potentials. The cytotoxicity results demonstrated higher toxicity of PF-AgNPs than St-PF-AgNPs in HEK293 cells. The antibacterial activity of St-PF-AgNPs were higher than PF-AgNPs in S. aureus. Overall, this work concluded that the starch encapsulation significantly increased the antibacterial activity of PF-AgNPs and this opens a new avenue for the treatment of bacterial infections through the sustained release of PF-AgNPs to target pathogenic bacterial cells.

Keywords: Antibacterial activity; Endophytic fungi; MRSA; Silver nanoparticles; Starch encapsulation.