Coating Method Uses Molecular Self-Assembly

Originally Published MDDI May 2002

R&D DIGEST

Specialized coatings are being used to enhance the performance of many medical devices, with results ranging from drug-eluting stents to catheters with increased lubricity and antimicrobial characteristics. Although many of these uses involve common materials, considerable research is being focused on developing more-effective methods for applying these coatings. Scientists at Virginia Polytechnic Institute and State University (Blacksburg, VA) are using the electrostatic self-assembly (ESA) process to incorporate ceramic biomaterials, water-soluble polymers, and heparin into ultrathin films for unique biocompatible materials with well-organized interfaces.

William B. Spillman Jr., director of the Optical Sciences and Engineering Research Center at Virginia Tech, notes that biocompatible thin films have been successfully fabricated on various biomedical substrates, such as the inner surface of polymeric medical tubing. "These films will have broad application, including antirestenosis coatings on medical devices such as stents, and hemocompatible coatings for dialysis tubing," he says.

Commenting on the use of coatings in the development of advanced stents, Spillman explains that, "in many situations where these devices are used, the body's response is not helpful." He adds that restenosis can be inhibited if the stents are coated with films incorporating the appropriate biochemicals. "The initial results are promising, but we have more research to do," says Spillman.

According to You-Xiong Wang, senior research scientist with the university's Fiber and Electro-Optics Research Center, "Prior to our biocompatible coatings work, our laboratory has been able to create via ESA nonlinear optical thin films incorporating polymer dyes, ceramic nanoparticle thin films, conductive thin film incorporating gold colloids, fullerene films, and light-emitting diodes." Other possible applications are tissue engineering, including bone implants, and scaffolds to restore damaged organ structure, the researcher says.

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