L-cysteine assisted synthesis of Bi2S3 hollow sphere with enhanced near-infrared light harvesting for photothermal conversion and drug delivery

Metal chalcogenide semiconductor nanomaterials are emerging as a promising photothermal and theranostic agent. In this work, uniform Bi2S3 hollow spheres (HS) have been successfully synthesized by using glycerol (Gly) and polyvinylpyrrolidone (PVP) as morphology regulator, and L-cysteine (L-Cys) as a sulfur source and surface modifier. The resulting L-Cys/Bi2S3 HS shows a stronger near-infrared (NIR) harvesting capability in comparison with its solid counterpart, and the photothermal conversion efficiency reached up to 31.5%. The nature of hollow structure endows the L-Cys/Bi2S3 HS with higher specific surface area and enhanced drugs loading capacity. As high as 86.4% doxorubicin (DOX) could be loaded to the outer and inner surfaces of L-Cys/Bi2S3 HS and their controlled releasing behavior follow a pH- and time-dependent manner. Meanwhile, the functional group of L-cysteine imparted the HS with good dispersibility and biocompatibility. The novel hollow materials with simultaneous integrated photothermal ablation and drug therapy may be a promising agent for cancer treatment. (C) 2019 Elsevier B.V. All rights reserved.