During transgenic research, micro-injectors use hollow needles to pump DNA-filled liquid into egg cell nuclei. That extra fluid causes the cell to swell and die 40% of the time, though, so researchers at Brigham Young University have developed a nano-scale lance that delivers DNA via electrical forces instead. It’s 10 times smaller and much more effective than previous technologies, according to the researchers.

“Because DNA is naturally negatively charged, it is attracted to the outside of the lance using positive voltage,” said Brian Jensen, BYU professor of mechanical engineering. “Once we insert the lance into a cell, we simply reverse the polarity of the electrical force and the lance releases the DNA.”

“The microinjection technology hasn’t really changed over the last 40 to 50 years since it was invented,” said microbiology professor Sandra Burnett. “Not having to force liquid into the nuclei by shifting to a lance is a huge advantage. It not only increases the survival rate, but it also causes less damage for future development.”

The researchers say that 77.6% of nano-injected mouse zygotes proceeded to the two-cell stage of development, compared to 54.7% for micro-injected zygotes. Also, DNA can be delivered to the cell’s nucleus without aiming the lance into the protonucleus, or the cellular structure containing the cell’s DNA. It then might be possible to perform injections in animals with cloudy or opaque embryos.

“Such animals, including many interesting larger ones like pigs, would be attractive for a variety of transgenic technologies,” said Jensen. “We believe nano-injection may open new fields of discovery in these animals.”

Researchers create transgenic animals to investigate genetic or infectious diseases. By modifying the genes of a mouse to carry a human disease, for example, researchers can generate data with insights into future treatments and therapies for those illnesses. More efficient injections, Jensen said, also should reduce the cost to create these animals.

The research is funded in part by $400,000 awarded to Jensen in 2011 through a National Science Foundation CAREER Award. It was first published in Review of Scientific Instruments. Quentin Aten, a former PhD student now with Nexus Spine LLC, served as the lead author.