Microinjection as a tool of mechanical delivery.

Microinjection to single cells has been widely used in the studies of transduction-challenged cells, transgenic animal production, and in vitro fertilization to mechanically transfer DNAs, RNA interferences, sperms, proteins, peptides, and drugs. The advantages of microinjection include the precision of delivery dosage and timing, high efficiency of transduction as well as low cytotoxicity. However, manual microinjection is labor intensive and time consuming, which limits the application of this technique to large number of cells in a sample. New cell culture matrix ensuring all cells grow in a desired position and orientation is needed for application of high throughput automatic injection systems, which will significantly increase injection speed, cell survival, and success rates.