Study on antibacterial activity of silver nanoparticles synthesized by gamma irradiation method using different stabilizers.

Colloidal solutions of silver nanoparticles (AgNPs) were synthesized by gamma Co-60 irradiation using different stabilizers, namely polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), alginate, and sericin. The particle size measured from TEM images was 4.3, 6.1, 7.6, and 10.2 nm for AgNPs/PVP, AgNPs/PVA, AgNPs/alginate, and AgNPs/sericin, respectively. The influence of different stabilizers on the antibacterial activity of AgNPs was investigated. Results showed that AgNPs/alginate exhibited the highest antibacterial activity against Escherichia coli (E. coli) among the as-synthesized AgNPs. Handwash solution has been prepared using Na lauryl sulfate as surfactant, hydroxyethyl cellulose as binder, and 15 mg/L of AgNPs/alginate as antimicrobial agent. The obtained results on the antibacterial test of handwash for the dilution to 3 mg AgNPs/L showed that the antibacterial efficiency against E. coli was of 74.6%, 89.8%, and 99.0% for the contacted time of 1, 3, and 5 min, respectively. Thus, due to the biocompatibility of alginate extracted from seaweed and highly antimicrobial activity of AgNPs synthesized by gamma Co-60 irradiation, AgNPs/alginate is promising to use as an antimicrobial agent in biomedicine, cosmetic, and in other fields.

Gamma irradiation of cotton fabrics in AgNO3 solution for preparation of antibacterial fabrics.

Silver nanoparticles (AgNPs) with diameter about 12 nm were immobilized on the surface of cotton fabrics by γ-irradiation of fabrics in the AgNO3 chitosan solution. Effects of absorbed dose, concentration of AgNO3 solution on immobilization of the AgNPs on fabrics were investigated. The optimal dose was selected to be 13.8 kGy and the suitable concentration of AgNO3 was 1.5mM in 1% chitosan solution. The content of AgNPs on fabrics was of 1,696 ± 80 mg/kg for these conditions. The presence of AgNPs on fabrics was confirmed from scanning electron microscopy (SEM) images and X ray diffraction (XRD) patterns. The antibacterial activity of AgNPs/cotton fabrics after 40 washings against Staphylococcus aureus and Escherichia coli was found to be 99.99%. In addition, the AgNPs fabrics were innoxious to the skin (k=0) after 1, 5, 10, 20, 30 and 40 washings by skin-irritation testing to animal (rabbit).

Radiation synthesis and characterization of hyaluronan capped gold nanoparticles.

Gold nanoparticles (AuNPs) with diameter from 4 to 10nm, capping by hyaluronan (HA) were synthesized using a γ-irradiation method. The maximum absorption wavelengths at 517-525 nm of colloidal AuNPs/HA solutions were measured by UV-vis spectroscopy. The size and size distribution of AuNPs were determined from TEM images. The influence of various factors on the size of AuNPs particularly the concentration of Au3+ and HA, and dose rate were also investigated. Results indicated that higher dose rate and HA concentration favor smaller sizes of AuNPs whereas the size increases with Au3+ concentration. The colloidal AuNPs/HA solution was fairly stable more than 6 months under storage at ambient condition. The AuNPs stabilized by biocompatible HA with the size less than 10nm as prepared can potentially be applied in biomedicines and cosmetics.