Improvement of delivery of molecules into corneal endothelium using nanoparticles activated by femtosecond laser pulses

Purpose NanoFemtoTransfection (NFT) is an innovative and promising technique of gene transfer (Nature nanotechnology 2011). It consists in permeabilizing cell membrane with nanoparticles (NP) of black carbon activated by Ti-Sapphire femtosecond laser (FsL) in order to safely introduce molecule of interest. Initially described for cell suspension, we adapted during last year NFT to human corneal endothelial cells (EC) Aim: to further optimize NFT of EC in vitro Methods The model of NFT of calcein (a small molecule) in an EC line (B4G12, DMSZ, Germany) was used to optimize exposition times, fluence and Ti-Saphir FsL beam movements in order to determine the best efficiency/toxicity ratio. Calcein transfer was observed with fluorescent microscopy (IX81, Olympus) and quantified by flow cytometry (FACSCalibur, BD, CA). Viability of EC was assessed by propidium iodide staining. Staining of actine with phalloidin and immunostaining of ZO-1 was performed to study cell alteration caused by NFT Results With a static laser beam increasing FsL fluence and exposure time increased transfection efficiency but also EC mortality. The use of mobile FsL beam (with a XY micrometric stage, cheaper than a scanner), permitted an irradiation of the entire area of EC culture resulting in a noticeably increased efficiency that reached 38% of transfected EC and a limited toxicity (3%). Calcein positive EC presented the same phalloidin and ZO-1 patterns as control EC Conclusion Optimized NFT parameters are currently being tested in our laboratory to transfect plasmids. Grants: Fondation pour la Recherche Medicale, Fondation des Aveugles de France