Photodynamic therapy (PDT) kills cancer cells by converting tumour oxygen into reactive singlet oxygen (1O2) using a photosensitizer. However, pre-existing hypoxia in tumors and oxygen consumption during PDT can result in an inadequate oxygen supply, which in turn hampers photodynamic efficacy.
In order to overcome this problem, researchers create oxygen self-enriching photodynamic therapy (Oxy-PDT) by loading a photosensitizer into perfluorocarbon nanodroplets.
Because of the higher oxygen capacity and longer 1O2 lifetime of perfluorocarbon, the photodynamic effect of the loaded photosensitizer is significantly enhanced, as demonstrated by the accelerated generation of 1O2 and elevated cytotoxicity.
Following direct injection into tumors, in vivo studies reveal tumor growth inhibition in the Oxy-PDT-treated mice. In addition, a single-dose intravenous injection of Oxy-PDT into tumor-bearing mice significantly inhibits tumor growth, whereas traditional PDT has no effect.
Oxy-PDT may enable the enhancement of existing clinical PDT and future PDT design.