Covalently grafting multihydroxy hyperbranched polymer on the surface of Ti3C2Tx MXene with remarkably enhanced colloidal stability and functionality for photothermal therapy

Abstract

While MXenes have garnered acknowledgment for their remarkable photothermal properties, their practical usage has been hindered by their limited stability in aqueous mediums and vulnerability to external environmental factors. To address this issue, herein, we propose a simple and feasible method to enhance Ti3C2Tx MXene by utilizing its Ti-OH groups to directly initiate the ring-opening polymerization of glycidol. This process leads to covalently grafting multihydroxy hyperbranched polyglycerol (HPG) on the surface of MXene. The resulting Ti3C2-HPG nanohybrid demonstrates excellent aqueous dispersibility, favorable colloidal stability, and a customizable surface, thanks to the introduction of HPG. Moreover, it can withstand challenging conditions, such as extreme pH levels, high concentrations of electrolyte and bovine serum protein, and long-time storage. The abundant hydroxyl groups allow for easy modification, as demonstrated by the conjugation of rhodamine B. Preliminary in vitro and in vivo studies have unveiled that Ti3C2-HPG exhibits low cytotoxicity and exceptional photothermal performance for effectively destroying cancer cells, thus establishing it as a highly promising photothermal agent for photothermal therapy. This study thus open a new avenue for improving the stability and surface functionality of MXenes, enabling them to meet the specific requirements of practical applications.