Luminescence-Tunable ZnS-AgInS 2 Nanocrystals for Cancer Cell Imaging and Photodynamic Therapy.

A highly luminescent I-III-VI group of semiconductor nanocrystals (NCs) has attracted considerable attention for applications in biomedical engineering and design of novel optoelectronic devices. In this work, high quality ZnS-AgInS 2 (ZAIS) solid solution NCs were synthesized by thermal decomposition of a organometallic diethyldithiocarbamate precursor complex of (AgIn) x Zn 2(1- x ) (S 2 CN(C 2 H 5 ) 2 ) 4 in the presence of specific stabilizing and structure directing agents. By changing the composition of the precursor complex (value of x ), the structure and optical property could easily be adjustable, thus leading to the formation of nanowire, nanorod, and tetrapod-like NCs and highly luminescent green to yellow to red color tunable NCs. The ZAIS NCs were further transferred to aqueous medium by 3-mercaptopropionic acid (MPA) capping without losing any optical properties. The color-tunable, water-soluble, and biocompatible ZAIS NCs were utilized for the in vitro cellular imaging of human cervical cancer cells (HeLa cells) and showed intense localization in the cell cytoplasm after 6 h of incubation. In addition, the inherent photocatalytic property of ZAIS NCs under light illumination showed promising photodynamic therapy of cancer cells, and thus, ZAIS NCs could be a promising candidate for future biomedical applications.