Abstract
The last two decades revealed tremendous interest in nanoparticles synthesized via green synthesis and its wide spectra application first of all as effective antimicrobial agents. This research aims to conduct a green synthesis of silver nanoparticles (AgNPs) stabilized by amino acids and oligoproteins. Various conditions (conventional heat treatment, microwave irradiation, and UV-light irradiation pH and concentration of reagents) on yield and size of AgNPs during the synthesis were tested. Alkaline hydrolysate of paper wasp‘s nest was characterized using amino acid analysis, zeta potential, and SDS gel electrophoresis. The protein hydrolysate molecular weight distribution for AgNPs synthesis was predominantly in the range of 0.5 to 10 kDa. The kinetics of the particle synthesis was monitored via intensity change of the AgNPs’ Surface Plasmon resonance UV–V is spectroscopy. The increase of the ionic strength of the AgNP suspension by the addition of salts NaCl and KBr led to aggregation of AgNPs. Zeta potential and hydrodynamic particle size distribution of AgNPs were −46 ± 25 mV and 137 ± 73 nm, respectively. Surface Plasmon resonance peak indicates the dominance of particle size in the range 50–70 nm due to the pH, which influenced on antimicrobial activity. MIC of 7.5 μM AgNPs in combination with 50 μM of benzalkonium chloride against the E. coli strain was (6.9xE8 particles/L) and 25 μM of benzalkonium chloride, while MIC of 73 μM of AgNPs (3.45xE8 particles/L) against Staphylococcus aureus was detected. The antimicrobial effect of the AgNPs suspension irradiated by light spectra at 425 and 630 nm were studied. AgNPs obtained using microwave radiation at a neutral medium were stable for at least 3 months at 4 °C.