Building a Better Biomaterial

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

Originally Published April 2000

If you ask Robert Ward a question about the latest developments in biomaterials research, you're likely to get a "shallow" answer: "There are a number of surface-modified polymers and materials for tissue engineering that need to be well-characterized in order to relate the surface chemistry to whatever biofunctionality people are after. One of the interesting new analytic techniques—called 'sum-frequency generation'—was first proposed by professors in the physics department at UC Berkeley. It gives characteristic vibrational spectra of only a material's surface—basically the top monolayer. Because it works in real time under water and protein solutions—and theoretically under blood—it is very well suited for biomaterials."

Such advances in the ability to analyze and ultimately control the surface properties of materials at biological interfaces are critically important to those, like Ward, who are designing new polymers for use in the body (see Thermoplastic Silicone-Urethane Copolymers: A New Class of Biomedical Elastomers in this issue). "We're trying to understand the relationship between the bulk makeup of polymers and their surface composition. Previously, we've had to rely on techniques that look almost too deeply into the bulk. With sum-frequency generation, to the extent that you can measure the relevant interfacial depth, you have a much better way to control the biofunctionality of the material, and ultimately even its manufacturing process."

Ward's company, The Polymer Technology Group Inc. (PTG; Berkeley, CA), was one of those that maintained supply lines to the industry during the days of acute shortages of certain materials. "We got a jump start on our business because of the biomaterials crisis," says Ward, "when people came to us and had us make clones of a bunch of materials." Despite the Biomaterials Access Assurance Act, which became law in 1998, the underlying conditions have not changed radically, according to Ward. "We do a lot of work in orthopedics, and ultrahigh-molecular-weight polyethylene (UHMWPE) is the most commonly used polymer in orthopedic products—hip joints, knee joints, prosthetic disks. I know of a survey that was done just in the last few months indicating that there are only one or two companies out of perhaps a dozen producers of UHMWPE that will even sell to the medical industry. Biomaterials are just a pain to large chemical producers, who want to sell train-car quantities. They always see it as too much liability for too little sales—and that hasn't changed."

Although Ward's goals for his own firm are quite different, in some areas the company has closed the gap on larger suppliers. Discussing PTG's 32,000-sq-ft facility, Ward notes that "we've set up a substantial manufacturing operation, so that we can go through the whole development and scale-up process real quickly. For years, only big companies had that capability." PTG is also moving beyond its initial focus on new polymer synthesis to encompass the production of actual devices. "We've been doing device development all along," says Ward, "mostly in the form of supply agreements for clients. Our business model is to have an R&D enterprise that generates future opportunities for the manufacturing subsidiaries. While our first manufactured products were unconfigured polymers for other people, we're integrating forward to make configured articles and, eventually, full devices."

Ward finds the present to be an extremely stimulating time for biomaterials researchers. "I see more things coming out now—new compositions of matter for biomaterials—than I have for a long time, partly because of tissue engineering approaches and the merging of biotechnology and medical devices. It's very exciting—there's just a lot going on."

Jon Katz is editor of MD&DI.

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