Glutathione-responsive folic acid modified fluorescent SBA-15 nanocarrier for simultaneous imaging and drug delivery in prostate cancer treatment.

The integration of imaging modalities and drug transport strategies has opened up exciting and innovative possibilities for simultaneously tracking and treating cancer, pushing the boundaries of current advancements. In this study, SBA-15 mesoporous silica nanoparticles (SBA-15 MSN) with a potent fluorescence emission were synthesized by a sol-gel method for targeted drug delivery. The enzalutamide (ENZ, anticancer drug) and folic acid (FA, targeting agent) were covalently conjugated to SBA-15 and the resulted FA-SBA-15/ENZ was loaded with thiolated nitrogen-doped carbon dots (SNCDs) as a fluorescent label for imaging. The drug loading efficiency was up to 69.95% and the disulfide linkage between the drug and SBA-15 provided the nanocarrier with redox-responsive capability for controlled drug release, and could be degraded by reducing agents such as dithiothreitol (DTT) or glutathione (GSH). The drug release behavior of the FA-SNCD@SBA-15/ENZ in the presence of GSH was very different from that in DTT as the loaded ENZ could be quickly released in the presence of GSH, but not in DTT. In addition, the toxicity of the synthesized nanocarriers with a certain amount of drug was evaluated using an MTT assay. The developed FA-SNCD@SBA-15/ENZ multifunctional nanocarrier showed higher cytotoxicity compared with the untreated drug and nanoparticles in the PC3 human prostate cancer cell line.