Hollow Mesoporous Silica Nanoparticles Co-Loaded with Docetaxel and Indocyanine Green for Synergistic Chemo–Photothermal Therapy

Hollow mesoporous silica nanoparticles (HSNs) were synthesized via the Stöber method using resorcinol–formaldehyde resin as a template and further developed as a multifunctional nanocarrier for synergistic chemo–photothermal therapy. Docetaxel (DTX) and indocyanine green (ICG) were co-loaded into HSNs as the prodrug and photothermal agent. The loading sequence of these agents can critically affect encapsulation efficiency. Preloading DTX followed by ICG incorporation achieved the highest drug loading (38.65%) and preserved the photoactivity of ICG. The resulting ICG&DTX@NH2-HSNs exhibited strong and stable near-infrared photothermal conversion, as well as pH- and laser-responsive drug release behavior. In vitro studies confirmed efficient cellular uptake by 4T1 tumor cells and enhanced cytotoxicity compared with single treatments. In vivo experiments demonstrated significant tumor growth suppression in 4T1 tumor-bearing mice, with the greatest effect observed under combined ICG&DTX@NH2-HSNs and laser irradiation. Importantly, histological analysis of major organs revealed no obvious toxicity, confirming the biosafety of the present nanoplatform. This study confirmed the potential of hollow mesoporous silica-based nanocarriers as safe and effective platforms for combined chemotherapy and photothermal cancer therapy.