The introduction of new genes into cells is normally done on a large scale and statistical methods are used when analyzing the effects. Moreover, these methods often shoot DNA strands into cells at high pressure, breaking cell membranes and causing unnecessary damage.
Researchers at South Korea’s Gwangju Institute of Science and Technology have developed a much more gentle technique that uses a laser to create a hole in the membrane and “optical tweezers,” specialty lasers that create a electromagnetic field that can manipulate small objects, to slowly move a DNA strand inside the cell.
From the Optical Society:
The researchers first moved the particle to the surface of the cell membrane. Guided by the trapped particle, they then created a tiny pore in the cell membrane using an ultra-short laser pulse from a femtosecond laser. While another laser beam detected the exact location of the cell membrane, they pushed the particle through the pore with the tweezers. Using this technique, the scientists were able to ease a microparticle right up to the pore in the membrane and drop it into the cell, like a golfer sinking an easy putt.
To determine whether their method had succeeded, the researchers inserted plasmids carrying a gene that codes for a green fluorescent protein. Once inside the cell, the gene became active and the cell’s machinery began producing the protein. The researchers could then detect the green glow using a fluorescence microscope. They found that approximately one in six of the cells they studied became transfected. This rate is lower than that recorded for some other methods, but those are less precise and involve many cells at a time.
Study in Biomedical Optics Express: Single-cell optoporation and transfection using femtosecond laser and optical tweezers