One-pot green reduction and surface decoration of graphene oxide nanosheets with PEGylated chitosan for application in cancer photothermal therapy

Background: The practical applications of reduced graphene oxide (rGO) nanosheets in cancer photothermal therapy (PTT) are still largely limited by their poor dispersion in serum-containing environment, irreversible aggregation and potential cytotoxicity.Methods: To conquer the above challenges, in this work, the PEGylated chitosan20k (PCS20k)-decorated rGO (PCS-rGO) nanosheets were developed by one-pot green reduction and PEGylation of GO nanosheets using PCS as a novel reducing and stabilizing agent.Significant findings: In addition to the decreased particle size, the reduction degree of GO nanosheets was significantly increased by raising the mass ratio of PCS20k and GO from 4/1 to 16/1. Notably, in the high salt and serum-containing milieu, distinct from GO nanosheets with massive aggregation, the PCS20k-rGO nano sheets exhibited virtually unchanged particle size (ca. 170 >> 200 nm), indicating their prominent dispersion due to the nearly neutral and PEG-rich surfaces. Importantly, under 808 nm near-infrared (NIR) irradiation, the PCS20k-rGO nanosheets exhibited photothermal conversion efficiency (77 = 67.7%) superior to GO nano sheets (77 = 55.0%). The in vitro cellular uptake and cytotoxicity studies revealed that the internalized PCS20k-rGO nanosheets effectively ablated cancer cells upon NIR-elicited hyperthermia (over 49 degrees C), suggesting their great potential in applications of cancer PTT.(c) 2022 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.