Enhanced photothermal bactericidal activity of chemically reduced graphene oxide stabilized by tripodal amphiphile

Highly water-dispersible and strongly near IR absorbing chemically reduced graphene oxide (rGO)/CP750 assembly was firstly prepared through noncovalent approach from graphene oxide (GO) and CP750, a cyclotriphosphazene ring-based tripodal amphiphile. Through the stable noncovalent interaction by tripodal CP750 amphiphiles, rGO/CP750 assembly presented both high absorption coefficient of 2260 L g(-1) m(-1) and high near infrared (NIR) absorbance (1.07 at rGO concentration of 0.05 wt.%) in aqueous media without forming precipitates for a long term storage. Upon NIR laser (808 nm) irradiation, rGO/CP750 presented high photothermal heat generating ranging from + 34.1 to + 78.0 degrees C depending on the assembly concentration. Finally, excellent photothermal bactericidal performance of nearly 100% was accomplished toward both E. coli and S. aureus even at a low concentration of assembly (0.1 mg/mL) within 10 min of NIR irradiation. In overall, our study shows that high photothermal bactericidal performance that has been mainly claimed by other strongly NIR absorbing nanomaterials such as gold nanorods and semiconducting polymers can be easily accomplished from rGO-based nanomaterials with the proper utilization of tripodal amphiphiles. (C) 2018 Published by Elsevier B.V.