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Making the Human Body More Hospitable
Kevin
Healy uses liquid nitrogen chambers to store and preserve frozen living cells that can be thawed later for experiments. Peg
Skorpinski photo
(Click for larger image.) |
The human body hates houseguests. That's why artificial hip and knee replacements, dental implants and vascular stents are tricky business. Typically, cells sense an object's alien nature and react against it. Meanwhile, implants frequently come lose from the surrounding bone, requiring additional surgery. To help solve the problem, UC Berkeley bioengineer Kevin Healy is developing a coating for prosthetics that not only convince the human body that the implant is "one of its own," but also send out a biological call for cells to begin healing.
Healy, who holds a joint faculty appointment in the bioengineering and materials science department, and his students are designing microscopic surface materials, thousands of time thinner than a human hair, to coat implants. The coatings are biomimetic, designed to imitate certain biological processes and synthesized from combinations of peptides ‚ strings of amino acids on a protein ‚ that trigger specific cell functions.
"First we're trying to circumvent the body's natural healing process," says Healy, who hopes to bring the coatings to clinical trials in three to five years. "Then we want to maximize the body's natural ability to recognize certain pieces of information that we can exploit to our advantage in situations like wound healing."
For a recent National Institutes of Health-sponsored project, Healy and his group synthesized materials that signal bone-producing cells to kick into action. Indeed, an experimental total hip replacement in a rat resulted in bone growth around the titanium rod treated with the bioengineered coating.
Healy is also developing a smart gel, an injectable variation of the technology consisting of polymer and water and peppered with his peptides. The hydrogels, which so far have successfully generated cartilage in the laboratory, could be employed in minimally invasive surgery such as arthroscopy to repair joints. The smart gel could also be used as a biomimetic caulk of sorts, filling in gaps between bone and prosthetics to promote bone regeneration.
"In this context, one almost has to think of an implant as a drug," Healy says.
Kevin Healy's Home Page: www-bioeng.berkeley.edu/faculty/healy.html
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research underway today at the College of Engineering that will dramatically change our lives tomorrow.
Lab Notes is written by David
Pescovitz.
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