Protein-modified hollow copper sulfide nanoparticles carrying indocyanine green for photothermal and photodynamic therapy

A novel phototherapy nanoplatform is prepared by coating hollow CuS nanoparticles with a bovine serum albumin-folic acid (BSA-FA) complex. The obtained CuS-BSA-FA nanoparticles are used as drug-delivery vehicles to transport a near-infrared-absorbing phototherapeutic agent (indocyanine green, ICG) into HeLa cells, after loading ICG onto CuS-BSA-FA. In this manner, a combined therapy approach is established consisting of photothermal therapy (by CuS-BSA-FA nanocarriers) and cytotoxic effects of photodynamic and photothermal therapy (by ICG upon 808 nm laser irradiation). The encapsulation of ICG onto CuS-BSA-FA significantly improves the stability and reduces the dark toxicity of free ICG. This therapeutic system exhibits an obviously higher photothermal heating effect and capability of O-1(2) generation under laser irradiation compared with bare nanocarriers. In addition, the grafted FA segments on the surface of CuS-BSA-FA are proved to enhance the internalization of nanoparticles by FA-receptor-mediated endocytosis.