Nanoparticles in Photodynamic Therapy

The application of nanoparticles in photodynamic therapy (PDT) has been a major stride forward in resolving some of the challenges associated with classic photosensitizer (PS). These nanoparticles are very versatile due to the existence of a variety of polymers and manufacturing methods, and thus the chemical composition and architecture of the nanoparticles can be customized to accommodate PSs with varying degrees of hydrophobicity, molecular weight, or charge. Furthermore, the surface properties, morphologies, and compositions of polymeric matrices can be easily optimized to achieve controlled degradation of the polymer and drug release kinetics. PDT using upconversion nanoparticles (UCNs) doped with PS is becoming the new sensation in the field with clear advantages over most other nanoparticles. UCNs act both as carriers of PS as well as enables indirect excitation of the accompanying PS with upconverted light upon excitation with low energy NIR light. The future of PDT lies in the development of a single versatile and efficient nanoparticle that encompasses its applicability in both bioimaging as well as PDT.