Effect of silver-based products on simulated body fluids

Zeolites A, Y, clinoptilolite, bentonite and kaolinite were applied as a carrier material to attach antibacterial agents of silver ion (Ag+) (Silver based product (Ag-BP)). They were analyzed by EDX and FTIR spectroscopy and showed that the Ag+ attached on the zeolites and clays while the main structure of them did not change significantly. The effects of Ag-BP on simulated body fluid (SBF) and simulated gastric fluid (SGF) were studied in different concentrations. The chemical framework variations of Ag-BP were analyzed by FTIR spectroscopy after contact with SBF and SGF. In FTIR, the most important structural peaks were same as those parents represent Si-O-Si and Si-O-Al bands. The antibacterial activity of Ag-BP was studied by Kirby-Bauer method against Escherichia coli and the inhibitory zones were found in this assay showing that they have antibacterial activity. Ag-BP had more structural variation after contacted in SGF (pH: 1.2) than SBF (pH: 7.4). With increasing concentration of adding Ag-BP to SGF and SBF, more changes were occurred on their structures. Strong acidic condition in SGF created an acidic attack to Si-O-Si and Si-O-Al bands in main frameworks of SBP. Due to this attack, some bonds such as Si-O-Si and Si-O-Al in Ag-BP were changed and caused to release their chemical agents in SGF. Interactions between SBF and Ag-BP were insignificant because the pH of SBF was not changed after addition of SBPs in SBF. In conclusion, certain structural changes were observed in the framework of Ag-BP and SGF when adding together while these changes were not significant for Ag-BP in SBF.