Originally Published MDDI April 2005
|A miniature violet laser beam focuses on a cell, which opens the membrane and enables genes to enter.|
A new technique that uses laser light to send genes to cells shows promise for making gene therapy safer and more precise. Eventually, the breakthrough could lead to the development of an endoscopic device for use in the delivery of anticancer drugs and in various gene therapy applications.
The method is cheap and powerful. A miniature violet laser beam, with a wavelength of about 4 or 5 nm, is focused through a microscope and onto cell membranes. It is only concentrated for a fraction of a second, but it is enough time for genes to enter as the membranes open.
“With the laser, we can look at the cells under the microscope, choose which cells we want to alter, and then have a cell exposed to the laser,” says Lynn Paterson, PhD, researcher at the University of St. Andrews (St. Andrews, Scotland). “We can choose the cell that we want to take off the DNA.”
|Cells that have had new genes inserted create proteins shown here stained with fluorescent red and green.
Researchers check these proteins to verify the gene's presence.
Paterson also says the technique could potentially be used for dyes, drugs, or proteins. The novelty, she explains, is in the laser's strength and size. “There have been lasers used before to photo-create cells, but they all involved very-high-power pulse lasers. The laser that we used is low-power continuous wave, less than 1 mW, and very compact.” So far, there has been no lasting damage to the DNA or to the cells themselves.
According to Paterson, any opportunity to improve the process of directing foreign material into cells, whether DNA, proteins, or any drugs, is going to be useful. In gene therapy, however, there's a possible danger when placing viruses into human cells.
It's too early to tell whether the research will lead to the development of a medical device. It may be possible, Paterson says, to attach a laser to an endoscope through a fiber. A lens at the end of the fiber would enable a more-precise focus on the targeted cells.
The research didn't begin as a medical experiment, but as a very basic biology experiment with hamster cells and DNA. It will take time for a medical device to be developed and used with gene therapy. “The way that we've experimented involves putting the cells on a dish,” says Paterson. “It would be completely different to translate cells that would have to be implanted back into humans. In the long term, we're focusing on creating medical devices, but we're still in the first stages of these experiments.”
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