Optical transfection is a biomedical technique that entails introducing nucleic acids (i.e.
genetic material such as
DNA) into cells using light. All cells are surrounded by a
plasma membrane, which prevents many substances from entering or exiting the cell. Lasers can be used to burn a tiny hole in this membrane, allowing substances to enter. This is tremendously useful to biologists who are studying disease, as a common experimental requirement is to put things (such as DNA) into cells.
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
fluorophore
A fluorophore (or fluorochrome, similarly to a chromophore) is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromatic groups, or planar or cyclic molecules with se ...
s, 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.
This technique was first demonstrated in 1984 by Tsukakoshi et al., who used a frequency tripled Nd:YAG to generate stable and transient
transfection
Transfection is the process of deliberately introducing naked or purified nucleic acids into eukaryotic cells. It may also refer to other methods and cell types, although other terms are often preferred: " transformation" is typically used to des ...
of normal rat kidney cells. Since this time, the optical transfection of a host of mammalian cell types has been demonstrated using a variety of laser sources, including the 405 nm continuous wave (cw), 488 nm cw,
or
pulsed sources such as the 800 nm femtosecond pulsed Ti:Sapphire
or 1064 nm nanosecond pulsed Nd:YAG.
Terminology
The meaning of the term
transfection
Transfection is the process of deliberately introducing naked or purified nucleic acids into eukaryotic cells. It may also refer to other methods and cell types, although other terms are often preferred: " transformation" is typically used to des ...
has evolved. The original meaning of transfection was "infection by transformation", ''i.e.'' introduction of DNA (or RNA) from a prokaryote-infe