Synthesis of SDF-1α-loaded chitosan nanoparticles coated with photosensitizer chlorin e6 for smart near IR light-controlled drug release

This work aims to design a stimuli-responsive photosensitizer chlorin e6 (Ce6)-coated stromal-cell-derived factor-1α (SDF-1α)-enclosed chitosan nanoparticles (Ce6-CNs-SDF-1α) by the ionotropic gelation method and investigate its photocontrol sustained-release properties by using near-infrared (NIR) light. The studies highlight these Ce6-CNs-SDF-1α fine particles with a size of 90–135 nm, charge of −32 ± 0.7 mV, and a spherical shape and smooth surface morphology. The positively charged chitosan and negatively charged tripolyphosphate (TPP) interaction along with SDF-1α and Ce6 was based on electrostatic interface between protonated amino and deprotonated phosphate groups. The photoinduced singlet oxygen generation (SOG), in which the ground state triplet oxygen (3O2) was excited into higher energy state singlet oxygen (1O2) as a result of energy transfer, was determined by the p-nitrosodimethylaniline (RNO) method with 660 nm irradiation. This indicated that the therapeutic activities were not changed after Ce6 being enclosed with CNs. The investigation comprised the Ce6 and SDF-1α releases from Ce6-CNs-SDF-1α as a function of time at pH 7.2. These compounds were found to have greater biocompatibility and no cytotoxicity as evaluated with the fibroblast cell lines from human skin by Alamar Blue assay and observed by confocal images. These smart NIR-responsive CNs can have potential uses in light-driven SDF-1α delivery for various diseases.