363. Laser-Triggered Gold Nanoparticle-Assisted Cell Poration for Selective Gene Delivery

Abstract

We present an innovative approach using laser-triggered plasmonic gold nanoparticles to selectively transfect cells. This method emerged from the combination of the recent progress in photonics and nanotechnologies. To perform the laser-triggered delivery, spherical gold nanoparticles (d=100 nm) were first dispersed onto cells in vitro in a medium containing fluorescent molecules or exogenous genes, and then irradiated with a scanning picosecond laser beam at high repetition rate (f = 76 MHz, wavelength λ =1064 nm, pulse width τ = 7.5 ps). When irradiated under appropriate conditions, the gold nanoparticles locally amplify the laser energy (plasmonic effect) and create transient pores on the cell membranes, allowing the penetration of surrounding molecules or genes through the plasma membrane by fluid exchange. After the delivery, the cell membranes rapidly self-reseal and the cells continue to thrive. Our technique presents several advantages: First, the method is safe. Gold nanoparticles are biocompatible and are believed to be non-toxic both in vitro and in vivo at low concentration. The emitted laser energy in the near infrared is weak and harmless to the tissue, and is only amplified in the nearfield of gold nanoparticles within submicron distance. Second, the transfection is temporally and spatially controlled by the pattern of irradiation. Gold nanoparticles can be conjugated to selectively target and transfect desired cell populations. We performed experiments on different cell types including breast cancer cells, ocular epithelium cells and neurons. Cell poration efficiency increased with laser energy up to a certain threshold, and decreased as mortality became important at higher irradiation fluence. The optimal conditions for irradiation vary from one cell line to another. The general poration efficiency could reach 30-70% depending on the cell line, with mortality as low as < 3%. Ongoing in vitro and ex vivo experiments will be presented. Our studies suggest that the laser-triggered gold nanoparticle-assisted cell transfection is a promising physical delivery method enabling efficient, safe and selective gene delivery in a variety of cells. It is anticipated that it would be an increasingly useful tool for the development and improvement of new gene therapy for prevalent diseases such as cancers or neural degenerative diseases.