NIR stimulus-responsive core-shell type nanoparticles based on photothermal conversion for enhanced antitumor efficacy through chemo-photothermal therapy.

A novel core-shell type nanoparticle (CSNP) was designed here to target co-delivery of doxorubicin (DOX) and photosensitizer indocyanine green (ICG) to tumor sites by the aid of NIR induced photothermal conversion effect for the purpose of synergistic chemo-photothermal cancer therapy. The electrostatically self-assembled CSNPs were prepared by amino-functionalized mesoporous silica nanoparticles (MSN-NH2 ) as the positive inner core and DSPE-PEG2000 -COOH and DSPE-PEG2000 -FA modified lecithin as the negative outer shell. The obtained CSNPs were nanospheres with a uniform size of 47 nm, which were kept stable at 4 °C in PBS (pH = 7). Research on the release of NIR stimulus (808 nm, 1.54 W cm-2 , 6 min) manifested that the release property of the CSNPs was controllable under low pH conditions. In addition, specific concentration (40 μg ml-1 ) ICG-loaded CSNPs, achieving an appropriate temperature up to 45 °C, indicated a desired photothermal conversion efficiency. For targeting the folate receptor, the folate modified CSNPs enabled us to reach a higher cellular uptake by the mean fluorescence intensity. In vitro cell assay, the prepared CSNPs showed outstanding inhibitory efficiency (2.07% cell viability and 91.8% cell apoptosis) on MCF-7 cells for 24 h when irradiated by an 808 nm laser with a power of 1.54 W cm-2 for 6 min. Our research highlights that the prepared nanoparticles hold potential promise for cancer treatment based on photothermal conversion performance and FA-targeted delivery.