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Gene Therapy Without a Needle
Needle is out: the new technique
uses electricity to “shoot” bits
of therapeutic bio molecules
through a tiny channel and into
a cell in a fraction of a second;
© panthermedia.net/Piotr Marcinski
Professor L. James Lee and his colleagues report successfully inserting specific doses of an anti-cancer gene into individual leukaemia cells to kill them. They have dubbed the method “nanochannel electro oration,” or NEP.
“NEP allows us to investigate how drugs and other bio molecules affect cell biology and genetic pathways at a level not achievable by any existing techniques,” said Lee, who is the director of the NSF Nanoscale Science and Engineering Centre for Affordable Nanoengineering of Polymeric Biomedical Devices at Ohio State.
There have long been ways to insert random amounts of biomaterial into bulk quantities of cells for gene therapy. And fine needles can inject specific amounts of material into large cells. But most human cells are too small for even the smallest needles to be of any use.
NEP gets around the problem by suspending a cell inside an electronic device with a reservoir of therapeutic agent nearby. Electrical pulses push the agent out of the reservoir and through a nanometre- (billionth of a metre) scale channel in the device, through the cell wall, and into the cell. Researchers control the dose by adjusting the number of pulses and the width of the channel.
Researchers used individual strands of DNA as templates for the nanometre-sized channels. Lee invented the technique for uncoiling strands of DNA and forming them into precise patterns so that they could work as wires in biologically based electronics and medical devices.
First, researchers tagged bits of synthetic DNA with fluorescent molecules, and used NEP to insert them into human immune cells. After a single 5-millisecond pulse, they began see spots of fluorescence scattered within the cells. They tested different pulse lengths up to 60 milliseconds – which filled the cells with fluorescence.
To test whether NEP could deliver active therapeutic agents, they inserted bits of therapeutic RNA into leukaemia cells. Pulses as short as 5 milliseconds delivered enough RNA to kill some of the cells. Longer pulses – approaching 10 milliseconds – killed almost all of them. They also inserted some harmless RNA into other leukaemia cells for comparison, and those cells lived.
“We hope that NEP could eventually become a tool for early cancer detection and treatment – for instance, inserting precise amounts of genes or proteins into stem cells or immune cells to guide their differentiation and changes – without the safety concerns caused by overdosing, and then placing the cells back in the body for cell-based therapy,” Lee added. He sees potential applications for diagnosing and treating leukaemia, lung cancer, and other tumours.
MEDICA.de; Source: The Ohio State University