Role of various nanoparticles in photodynamic therapy and detection methods of singlet oxygen

In this review article we described the applications of various nanoparticles that can be used for photodynamic therapy (PDT), such as: plasmonic nanoparticles, quantum dots and upconversion nanoparticles. In comparison with typical organic photosensitizers such as hematoporphyrins, they exhibit higher photostability and resistance to enzymatic degradation, and hence, in some cases, they could replace organic photosensitizers in PDT therapy. It has also been found that the presence of plasmonic noble metal nanoparticles increases the efficiency of conjugated standard photosensitizers. Therefore, one can expect that, due to their very promising optical properties, plasmonic nanoparticles, plasmonic composites, and upconversion nanoconjugates will have a significant impact on the detection and treatment of cancer in the near future. Various methods of detecting the singlet oxygen produced are also reviewed.