Efficient method for functionalization of carbon nanotubes by lysine and improved antimicrobial activity and water-dispersion

Here, multi-walled carbon nanotubes (CNT) were first functionalized with lysine under microwave irradiation. The water-dispersed CNT were obtained by diazonium-assisted functionalization. Formation of lysine on CNTs surface was confirmed by FTIR, TGA, Raman and TEM techniques. Then, by minimal inhibitory concentration (MIC), antimicrobial activity of functionalized and pristine CNT was studied on three Gram-negative bacteria as well as three Gram-positive bacteria. The MIC results show that functionalized CNT with lysine were more effective than pristine CNT against all studied bacteria. This simple and efficient mechanism could be used to CNT functionalization with molecules containing primary amine groups.

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► Both diazonium reaction and microwave method were employed for CNT functionalization.
► Grafting of lysine on CNT was confirmed by FTIR, TGA, Raman and TEM techniques.
► The rapid functionalization method leads to high water-dispersion.
► Antimicrobial activity of functionalized CNT studied on various bacteria.
► The functionalized CNT with lysine shows more effective destruction of bacteria.