Polyacrylamide‐Grafted MXenes Prepared via on‐Surface Polymerization Demonstrated Enhanced Aqueous Dispersion and Colloidal Stability

Abstract As a novel type of two‐dimensional materials, MXenes demonstrated great potential for biomedical applications due to their excellent photothermal and photodynamic properties. However, their exposed unmodified surface cannot ensure sufficient stability for MXene in a biological environment. Here, we developed an efficient method to modify the surface of MXenes in aqueous medium. A water‐soluble initiator was designed and covalently anchored onto MXene surfaces, which was used to initiate copper(I)‐catalyzed atom transfer radical polymerization to introduce a layer of water‐soluble polyacrylamide on MXene surfaces (PAM‐MXenes). Impressively, it was found that the grafting of the polymer layer on MXene surfaces greatly enhanced the colloidal stability of modified MXenes which remained well dispersed in cell culture medium for over 7 days and for over one month in water without aggregation or sedimentation. Furthermore, their photothermal properties were not influenced as the PAM‐MXenes demonstrated uncompromised heat‐generating capacities upon irradiation at 808 nm nor did they cause marked toxicity to cells. Thus, our work provided an effective approach to ameliorate the surface properties of MXene materials.