Traceable Nanocluster-Prodrug Conjugate for Chemo-photodynamic Combinatorial Therapy of Non-small Cell Lung Cancer.

In cancer treatment, image-guided combinatorial therapy is usually a more promising approach than conventional therapy because it may overcome the drawbacks of conventional cancer treatment, such as tumor recurrence and multidrug resistance. To achieve a high therapeutic effect in image-guided combinatorial therapy, the therapeutic material should be traceable, biocompatible, and yet highly effective in eradicating tumors. For this purpose, we developed a traceable nanocarrier consisting of atomically precise gold nanoclusters (Au NCs, Au 22 (SG) 18 , abbreviated as Au 22 NCs, where SG stands for glutathione) and a biopolymer ( i . e ., chitosan). This traceable nanocarrier (Chito-Au 22 ) was then combined with dual prodrugs ( i . e ., chemotherapeutic platinum (Pt(IV)) prodrug and photodynamic aminolevulinic acid (ALA) prodrug) through a bioconjugation method. It was found that the final nanocomposite (abbreviated as Pt(IV)-ALA-Chito-Au 22 ) has a pH-responsive drug release behavior, and the cumulative drug release can exceed 50% within 12 h at an acidic pH of 5.0. After 15 min of white light irradiation, the nanocomposite showed a synergistic killing effect on the A549 non-small cell lung carcinoma cell line. The Pt(IV)-ALA-Chito-Au 22 nanocomposite also showed a high cellular uptake capacity and reactive oxygen species (ROS) generation capability, resulting in a significant killing effect on three-dimensional (3D) multicellular A549 spheroids. In the presence of light, the volume of the multicellular spheroids treated by our nanocomposites was reduced more than two times compared with those treated by a single prodrug/component. The nanocomposite also showed good cell viability on normal lung cell lines. The multifunctional nanocomposites developed in this study have broad prospects in both therapeutic and diagnostic applications.