A pH-Responsive Multifunctional Nanocarrier in the Application of Chemo-Photodynamic Therapy

In cancer therapy, combined utilization of anticancer drug and photosensitizer attracts increasing interest due to enhanced curative effects and reduced side effects. Since the drug delivery system is an effective method to enhance curative effects, drug carriers for codelivery of the two abovementioned molecules are essentially important for chemophotodynamic therapy. Based on the foundation, a nanocarrier with pH-responsive and targeted properties was designed, prepared, and researched in the work. A pH-sensitive nanoparticle was fabricated by acetylated β-cyclodextrin (Ac-β-CD) using oil-in-water (O/W) emulsion technique. During the fabrication processing, a functional emulgator (gelation-folic acid ester (G-FA)) with a biorecognition domain was absorbed onto the surface of the nanoparticle, which endowed a nanoparticle-targeted property. The nanoparticle exhibited a coarse surface, pH-responsive property, and similar fluorescence characteristic as G-FA. The cell endocytosis profile revealed that equilibrium endocytosis could be reached after being cocultured with 1.0 mg/mL nanoparticle for 8 h. Furthermore, camptothecin (CPT) as an anticancer drug and phthalocyanine (PcZn) as a photosensitizer were encapsulated into the nanoparticle during the fabrication processing. The nanoparticle enhanced the fluorescence effects of PcZn on water solution, and CPT encapsulation proportion was slightly influenced by initial CPT concentration. The pH value influenced the PcZn fluorescence behavior and CPT release behavior of the nanoparticle. In vitro cytoviability evaluation confirmed the therapeutic effect of the nanocarrier on HEP2 cells. Finally, the results of preliminary in vivo evaluation revealed that the reported nanocarrier in the research could inhibit cancer development with little effects on the body weight of mice.