Photodynamic therapy (PDT) is a promising alternative to conventional cancer treatment methods. Nonetheless, improvement of in vivo light penetration and cancer cell-targeting efficiency remain major challenges in clinical photodynamic therapy. This study aimed to develop multifunctional magnetic nanoparticles conjugated with a photosensitizer (PS) and cancer-targeting molecules via a simple surface modification process for PDT. To selectively target cancer cells and PDT functionality, core magnetic (Fe₃O₄) nanoparticles were covalently bound with chlorin e6 (Ce6) as a PS and folic acid (FA). When irradiated with a 660-nm long-wavelength light source, the Fe₃O₄-Ce6-FA nanoparticles with good biocompatibility exerted marked anticancer effects via apoptosis, as confirmed by analyzing the translocation of the plasma membrane, nuclear fragmentation, activities of caspase-3/7 in prostate (PC-3) and breast (MCF-7) cancer cells. Ce6, used herein as a PS, is thus more useful for PDT because of its ability to produce a high singlet oxygen quantum yield, which is owed to deep penetration by virtue of its long-wavelength absorption band; however, further in vivo studies are required to verify its biological effects for clinical applications.
Keywords: cancer cell targeting; chlorin e6; folic acid; in vivo penetration depth; multifunctional magnetic nanoparticles.