A promising strategy for increased intracellular delivery of nucleic acids with the benefit for targeting is photochemical internalization (PCI). PCI relies on the use of a photosensitizing compound that photochemically destroys membranes in the endocytic pathway after illumination, resulting in cytosolic transfer of endosomal content. PCI technology combined with biodegradable polyamino acid carriers and nucleic acids delivers effective targeting and improved biosafety. In an in vitro model system, we have evaluated various poly-l-lysine (PLL), poly-l-histidine (PLH), and poly-l-arginine (PLA) formulations for light-directed small interference RNA (siRNA) gene silencing and messenger RNA (mRNA) delivery. We find that PLA formulations are suitable as siRNA and mRNA carriers in a strictly light-directed manner.