Quaternary ammonium salts (QAS) have been widely applied in daily life because of their antibacterial properties. However the antibacterial effects of QAS cannot be effectively utilized due to the uncontrolled release. In this work, dodecyl dimethyl benzyl ammonium chloride (1227) and bromohexadecyl pyridine (CPB) were assembled on surfaces of graphene oxide (GO) through pi-pi interactions to form GO/QAS nanocomposites, i.e., GO-1227 and GO-CPB. In the comparison with pure CPB and 1227, GO-CPB and GO-1227 nanomaterials show biocompatible with reduced cytotoxicity. We found that GO could increase the antibacterial effect when the weak antibacterial agent was adopted. Remarkably, GO-1227 has exhibited stronger antimicrobial properties then GO-CPB, while GO-CPB has shown long-term slow-release antibacterial properties and CPB is facile to be loaded on GO surfaces. (C) 2016 Published by Elsevier B.V.