Preparation and antibacterial properties of cetylpyridinium bromide modified silver-loaded kaolinite

Abstract

A system of dual antibacterial agents loaded onto kaolinite (Kao) as carrier has been developed by attaching cetylpyridinium bromide (CPB) onto Ag-loaded Kao (Ag-Kao). The analysis of CPB adsorbed onto Ag-Kao and characterisation of the CPB-Ag-Kao systems using X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectroscopy and Fourier-transform infrared (FTIR) spectroscopy demonstrated that the CPB molecules attached onto Ag-Kao and no changes occurred in the Kao structure. The antibacterial effect of different amounts of CPB and Ag attached onto Kao was investigated against Gram-positive (Staphylococcus aureus ATCC 6538) and Gram-negative (Escherichia coli ATCC 11229) bacteria. The antibacterial activity of CPB-Ag-Kao was higher than that of Ag-Kao and the highest antibacterial activity was recorded for CPB-Ag-Kao loaded with 50% Ag and 1000% CPB, which satisfied the cation exchange capacity of Kao. The higher antibacterial activity of CPB-Ag-Kao against a wide spectrum of bacteria was due to the synergistic effects of the two antibacterial agents loaded onto Kao as carrier.