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Biomedical Engineering Student Invents Mechanical Leech

December 14, 2000 -- Leeches have been used in medicine for more than 3,000 years and Patrick Cottler thinks that’s long enough.

The benefits of using medicinal leeches, or Hirudo medicinalis, were first recorded by Themison Laodicea in 50 B.C. Indigenous to Europe and Southeast Asia, medicinal leeches feed on the blood of warm-blooded mammals. Historically, they have been used for a variety of ailments that bewildered the physicians of the day. Physicians of the Middle Ages relied heavily upon them. Even Napoleon’s military surgeon, Francois-Joseph-Victor Broussais, was such a firm believer in the medical benefits of leeches that in 1833, he had more than 40 million imported into France.

As medical knowledge has grown over the past 150 years, the role of the leech in healing has shrunk. However, leeches are still widely used after plastic surgery and other treatments involving the reattachment of skin flaps.

To reestablish blood flow and promote healing in skin flaps after surgery, surgeons not only must reattach arteries to enable the oxygen-rich blood to flow into traumatized tissue, they also must ensure that the blood flows through and out of the tissue into reconnected veins. With plastic surgery in particular, reattached skin flaps present a challenge in reestablishing blood flow. Strategically placed leeches can suck blood from such tissue, restoring blood flow and promoting healing.

Cottler a research associate in biomedical engineering at the University of Virginia, has invented a mechanical leech that he believes is superior to nature’s blood suckers in several ways — it is just as effective in drawing blood through traumatized tissue to reestablish blood flow, it doesn’t migrate from the affected site, it offers less risk of infection and it’s less likely to disgust patients.

Cottler's invention, which looks like a plastic box about two inches square, holds a series of hypodermic needles attached to a tiny vacuum pumping system that draws blood into a small, replaceable reservoir. The box is placed on the skin flap, with the needles puncturing the skin near the sutures. When activated, the vacuum pump draws blood through the skin flap and into the reservoir.

The invention won the Virginia Engineering Foundation’s 1999 award for biomimicry, an annual contest for engineering students at U.Va. who design machines that mimic biological processes.

Cottler believes that his mechanical leeches — to be called "smart bandages" for marketing purposes — offer enough advantages to patients and hospitals that he is building a company around his technology as he refines it.

"It's been very exciting to adapt a technology, originally designed by NASA, that will bring an age-old treatment into the 21st century," Cottler said.

The U.S. space agency developed an actuator, a mechanical device that creates negative pressure by sending electrical voltage through a thin sheet of a chemical compound. Cottler has adapted the actuator to supply the suction needed to draw the blood up through the needles and into the reservoir in his device.

Cottler defended his doctoral dissertation in biomedical engineering last summer. In the fall, he launched Cottler Technologies, LLC as a way to bring his idea to market. He has a patent pending for the technology and has applied for a Small Business Innovation Research (SBIR) grant to develop a working prototype of his invention.

If that pans out, Cottler plans to seek a second grant to refine the device, design it to work on battery power, and advance to animal, and later, human testing.

After that, who knows? The company’s name — Cottler Technologies — suggests there are more ideas where the mechanical leeches came from.

Contact: Charlotte Crystal, (804) 924-6858

FOR ADDITIONAL INFORMATION: please contact the Office of University Relations at (804) 924-7116. Television reporters should contact the TV News Office at (804) 924-7550.
SOURCE: U.Va. News Services


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