Bimodal surface modification strategies towards improving the antibacterial activity of graphene oxide

Herein, we have demonstrated and compared bimodal strategies towards augmenting the antimicrobial activity of graphene oxide (GO). Among the two modifications viz. through alteration of GO surface functionalities and secondly through surface modification of GO with an ampicillin-based antibacterial ionic liquid (IL), the IL modification was most effective in enhancing the bactericidal effect. pH and the zeta potential values of the nanodispersions support the alteration of surface functionalities of GO by variation in reaction conditions and SEM, XRD, Raman spectra establish the resulting sheet thickness, morphology, stacking and planarity. The surface modification of GO with trihexyltetradecyl phosphonium ampicillin ([TTP][Amp]) IL as indicated by FTIR, SEM, pH and zeta potential measurements imply in nearly five times lower MBC value compared to average MBC value of the four GO variants. Hence, judicious IL modification can be an effective approach towards augmenting antibacterial property of GO for enduring antifouling coatings and membranes. Graphical abstract