Effect of Different HDTMA Loading on Silver Modified Kaolinite on Its Antibacterial Activity
Muhammad Hariz Asraf (a), Nik Ahmad Nizam Nik Malek (a,b*)
a) Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia (UTM), 81310 UTM Johor, Malaysia.
b)Centre for Sustainable Nanomaterials (CSNano), Ibnu Sina Institute for Scientific and Industrial Research (ISI-SIR), Universiti Teknologi Malaysia (UTM), 81310 UTM Johor, Malaysia.
*niknizam[at]utm.my
Abstract
There have been purposeful researches in synergistic combination of organic and inorganic materials as antibacterial agent which aims to combine two or more antibacterial compounds in a carrier system. This research aimed to study the physicochemical properties of silver loaded kaolinite attached with different amount of cationic surfactant hexadecyltrimethyl ammonium (HDTMA) and its effect on Gram positive and Gram negative bacteria. Kaolinite was initially modified with silver ion and later, with different concentrations of HDTMA (50, 75, and 100% of CEC of the kaolinite). The samples were characterized using X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscope equipped with energy dispersive X-ray analyser. Antibacterial activity was evaluated using disc diffusion technique against Escherichia coli and Staphylococcus aureus. Characterization results showed that kaolinite was successfully modified with silver ion and HDTMA. For antibacterial assay, S. aureus was more susceptible than E. coli due to differences in their peptidoglycan structure. Surfactant-modified silver kaolinite was more effective in inhibiting bacterial growth than silver kaolinite with inhibition diameters of 2.3 cm and 1.7 cm, respectively. However, the different concentrations of HDTMA did not contribute to the inhibitory effects against the bacteria. Thus, the low concentration of HDTMA loaded on silver-kaolinite is suitable to be used as antibacterial agent.
Keywords: kaolinite; hexadecyltrimethylammonium bromide; silver ion; antibacterial
Topic: Biotechnology