Protein corona as a barrier compromises the photothermal antibacterial activity of graphene oxide nanosheets.

As an antibiotic-independent approach, photothermal therapy (PTT) demonstrates significant efficacy in combating bacterial infections. Many nanoscale photothermal agents (nano-PAs), such as graphene-based nanomaterials, MXene and metal-based nanoparticles, have been reported for PTT. However, how protein corona surrounding 2D nano-PAs influences the antibacterial PTT is still unknown. Herein, we used graphene oxide (GO) as a model 2D nano-PA and investigated the effects of bovine serum albumin (BSA) corona on the antibacterial PTT of GO. We found BSA corona enhanced the photothermal effect of GO in terms of temperature increase. Despite the increased temperature, BSA corona significantly compromised the antibacterial PTT of GO against the model pathogen methicillin-resistant Staphylococcus aureus (MRSA) (viability loss rate 94.3 % for GO but 62.3 % for BSA-GO). Results from scanning electron microscopy suggested that the interactions of BSA-GO with MRSA cells were attenuated by BSA corona. This may be the reason for the compromised antibacterial PTT of BSA-GO. Our findings highlight the importance of considering the impacts of protein corona on the efficacy of antibacterial PTT. This is the first report regarding the compromised antibacterial PTT of 2D nano-PA caused by protein corona formation, which may guide the design and applications of other nano-PAs in PTT.