Abstract: The translation of gene therapy from bench to bedside depends on efficient intracellular gene delivery. The macromolecular biologics such as gene combined with vectors tend to enter into the cells by means of endocytosis, where the biologics may encounter the risk of degradation in endolysosome. Recently, photochemical internalization (PCI) has emerged as a promising technique to overcome endo-lysosomal sequestration, which utilizes photosensitizer and light resulting in reactive oxygen species at sub-lethal level to destruct biofilm and facilitate intracellular drug delivery. In this article, the mechanism of PCI technology and its development for gene delivery were reviewed, which can provide the scientific basis for the possible utilization of PCI to solve the problem of endo-lysosomal escape in gene delivery.

Key words: gene delivery, photochemical internalization (PCI), photosensitizer, reactive oxygen species, endo-lysosomal escape