Laser transfection with gold nanoparticles: current state and new particle structures as a perspective

Laser-based transfection techniques have gained significant interest during the last decade. Either single cell manipulation by focusing on the cell membrane or high-throughput can be realized with laser transfection. The latter is for example provided by gold nanoparticle mediated laser transfection. It is based on the heating of gold nanoparticles through laser irradiation, which permeabilizes the membrane. This technique satisfies most prerequisites of a reliable transfection technique, like efficiency and minimal cell impact. In order to bring it closer to routine usage, we investigated new particle configurations for gold nanoparticle mediated laser transfection. Our setup employs a 532 nm and 850 ps laser system. We immobilized gold particles on cell culture surfaces or modified silica particles with a gold particle surface coverage. Furthermore, first experiments achieving cell perforation with an organic nanoparticle based on polypyrrole were conducted. These three options achieved comparable efficiencies to the incubation of cells with free gold nanoparticles. With regard to the underlying mechanisms of perforation, we performed fluorescence microscopy based imaging of the cell state combined with holographic imaging directly after perforation. First results indicated a power dependent ion (calcium) and volume exchange with the extracellular medium in the first two minutes after perforation. In conclusion, our results can pave the way to a safer and more efficient way of high-throughput laser transfection with gold nanoparticles.