▎ 摘　　要

Combination of chemotherapy and photothermal therapy (PTT) is an effective way for the treatment of cancer. Graphene oxide (GO) with a large specific surface area and strong near-infrared (NIR) absorbance have been widely used as both the chemotherapeutic carriers and photothermal agents. The smaller lateral size and higher oxidation degree of GO corresponding to better dispersion in water and lower cytotoxicity. Therefore, the preparation of ultrafine GO nanosheets (UGO) with the controlled size and high oxidation degree is of significant importance to meet the demands of biological applications. Herein, we developed a versatile drug delivery nanoplatform based on poly(dopamine) (PDA) modified ultrasmall graphene oxide (UGO) with small size (average size of 30 nm) and high oxidation content (45 wt. %). The fabricated PDA-modified UGO (UGP) exhibits well biocompatibility, excellent photothermal performance and high drug loading capacity of doxorubicin (DOX). Under NIR laser irradiation, the photothermal-induced release of DOX could achieve the combination of chemotherapy and PTT for efficient therapy of breast cancer. This work established UGO as a novel drug delivery with excellent photothermal performance for the combination of chemotherapy and PTT of tumors.