Efficient capture and photothermal ablation of planktonic bacteria and biofilms using reduced graphene oxide-polyethyleneimine flexible nanoheaters

Bacterial infections are one of the leading causes of diseases worldwide. Conventional antibiotics are becoming less efficient, due to antibiotic-resistant bacterial strains. Therefore, the development of novel antibacterial materials and advanced treatment strategies are becoming increasingly important. In the present work, we developed a simple and efficient strategy for effective bacteria capture and their subsequent eradication through photothermal killing. The developed device consists of a flexible nanoheater, comprising a Kapton/Au nanoholes substrate, coated with reduced graphene oxide-polyethyleneimine (K/Au NH/rGOPEI) thin films. The Au NH plasmonic structure was tailored to feature strong absorption in the near infrared (NIR) region, where most of biological matter has limited absorption, while PEI was investigated for its strong binding with bacteria through electrostatic interactions. The K/Au NH/rGO-PEI device was demonstrated to capture and eliminate effectively both planktonic Gram-positive Staphilococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacteria after 10 min of NIR (980 nm) irradiation and even more to destroy and eradicate Staphilococcus epidermidis (S. epidermidis) biofilms after 30 min irradiation. The technique developed herein is simple and quite universal with potential applications for eradication of different microorganisms.