2023 Volume 44 Issue 1 Pages 62-68
A drawback to carrier-based cytosolic delivery of biomolecules and drugs is that endosomal entrapment of cargoes (biomolecules and drugs) often occurs. Photochemical internalization (PCI) can be used to solve this shortcoming. In PCI, a photosensitizer is encapsulated in the endosome together with the cargo. The photosensitizer can then be photoirradiated to induce endosomal escape and cytoplasmic dispersion of the cargo. This method can deliver the cargo into the cytoplasm with almost no damage to the cells by irradiating with minimum necessary light. However, side effects including cytotoxicity are observed with increasing light intensity. Our recent results suggest that the cause of side effects is “photosensitizers adsorbed on the cell surface,” which are not necessary for PCI. In this study, prior to photoirradiation, we attempted to remove or inactivate photosensitizers on the cell surface by washing the cells, treating with serum, and quenching with trypan blue. We investigated the efficacy of these treatments at reducing the side effects of PCI. We used PCI-based photoinduced cytosolic dispersion of RNA (PCDR) to verify reductions in side effects.
