Biomimetic Silicones Take a Cue from Nature

Originally Published MPMN November 2001

INDUSTRY NEWS

Biomimetic Silicones Take a Cue from Nature

A team led by a professor at Queen's University Belfast (Northern Ireland) has developed a patented technology for the production of biomimetic silicone materials that can imitate the body's natural defense mechanisms.

With a coefficient of friction approaching zero, the silicone materials are highly lubricious. This property should enable their easy insertion and removal without pain or tissue trauma, says Sean Gorman, who is chair of the pharmaceutical microbiology department and head of the school of pharmacy at Queen's University. Gorman also heads up the school's medical devices group.

Another innovative feature of the silicones is that they are self-cleaning. Like the body's epithelial tissues, the materials can fight adhesion through the shedding and renewal of their surfaces. The silicones, which can be created at varying levels of hardness, can be processed using conventional methods and can withstand gamma irradiation.

The technology used to produce the materials relies on the use of higher-molecular-weight polysilanes as crosslinking agents for silicones. Gorman describes the chemical mechanism underlying the materials' increased lubricity using an analogy from nature. "It's like what might happen if you tried to hold a fish in your hand. It's a slippery surface that has been designed by evolution to prevent adhesion," he says. "We see our materials as offering this same characteristic by taking a lesson from evolution," he adds.

In addition, the enhanced lubricity of the silicones holds promise as a platform for drug delivery. Gorman notes that the materials can be tailored to deliver an active agent over a specific course of time, from days to months.

Gorman has formed a company, Xiomateria Ltd., to develop the materials. The enterprise, which is based at the university, will not manufacture products itself, but is seeking to license its technology to third parties. The company is currently in negotiations with a U.S. manufacturer.

According to Gorman, a further advantage of the new materials is that they do not present any substantive alterations from the RTV silicones currently used in medical devices. "They are made in the same manner, and there is no downside as far as cost is concerned," he says. Furthermore, he notes, they are "every bit as biocompatible as their parent substance."

Looking beyond the new silicones, Gorman makes both a technical and a philosophical case for a biomimetic approach to materials engineering. "Materials should mimic nature," he says. "It is arrogant for us as biomaterial engineers to assume that we can provide a replacement for a urethra or a vein by manufacturing a device from a single material." He adds that his team's approach has been "to combine the structural engineering in current device technology with new materials that offer the benefits of evolution."

Benjamin Lichtman

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