Optical transfection
Optical transfection is the process of introducing nucleic acids into cells using light. Typically, a laser is focussed to a diffraction limited spot (~1 µm diameter) using a high numerical aperture microscope objective. The plasma membrane of a cell is then exposed to this highly focussed light for a small amount of time (typically tens of milliseconds to seconds), generating a transient pore on the membrane. The generation of a photopore allows exogenous plasmid DNA, RNA, organic fluorophores, or larger objects such as semiconductor quantum nanodots to enter the cell. In this technique, one cell at a time is treated, making it particularly useful for single cell analysis.