Technology
Polymer implant facility set up at Utah University of Utah receives grant to fund activities of biomedical engineering center for developing replacement parts for the human body The University of Utah has long been one of the leaders in the field of devel oping replacement parts for the human body. Now the Salt Lake City school has established what it says is the U.S.'s first biomedical engineering center for poly mer implants. A $957,774 grant from the National Institute of General Medical Sciences will fund the center's activities for the next three years. About 20 scien tists, students, and support personnel will be employed there. Dr. Donald J. Lyman, a Utah bioengineer who is also a research associate professor of surgery, will direct the center. "Too often," Lyman says, "basic re search on biomaterials has been isolated
from end-use applications. We believe this is why, in spite of an increase in re search on materials for biomedical ap plications, there has not been an accom panying progress in the clinical and sur gical utilization of these materials." Lyman doesn't intend for that to happen at the new Utah center. Half the research funds will be used to develop implants for specific applications such as blood vessel, nerve, bile duct, ureter, and bladder repairs. The other half will go to basic research aimed at understanding how synthetic materials interact with living systems. Lyman will coordinate the total effort and also will directly supervise basic polymer research activities. Dr. Dominic Albo Jr., associate professor of surgery at the university's college of medicine, will oversee the applied projects. Basic research activities will include investigations of the interactions of pro teins, blood, tissue fluids, and cells with polymers. These studies are expected to provide data useful in the synthesis and process engineering of new or modified polymers. Other studies will involve the
New technical center consolidates Witco R&D Witco Chemical laboratory manager William Houser (left) and R&D vice president H. William Campbell check the progress of a chemical reaction being run in the synthesis lab at the company's new technical center. Located in Houston, the center consolidates and expands R&D formerly carried out in Chicago, Houston, and Burlingame, Calif., the company says. One major focus of work at the center is on crude oil demulsifier intermediates.
30
C&EN Feb. 13, 1978
design and fabrication of experimental implant devices, and the determination of short- and long-term interactions between the implant and its living environment. Lyman and Albo will act as joint project leaders on one task: development of sat isfactory small-diameter artificial blood vessels. Large-diameter prostheses of woven polyester have been used satisfac torily for years. But at diameters of less than 6 mm, the devices rapidly become clogged. The Utah workers have been developing replacements made of a new polyurethane-type material that expands and contracts as blood surges through it, just as a natural vessel does. Blood vessel grafts made of the new material and only 4 mm in diameter already have been working successfully in dogs, for as long as 14 months. Another goal is to perfect a polymer prosthesis to bridge gaps in peripheral nerves that have been injured or diseased. Peripheral nerves can regenerate them selves, but only if they have a suitable pathway along which to grow. The only effective material now available is normal nerve tissues from another part of the patient's own body. One approach that the Utah group is working on is to develop a "nerve cuff—a simple tube to prevent collagen ingrowth and other neurosurgical complications. However, the project goes beyond that. "From the work we've been doing with cell culture," Lyman says, "it looks as if we can provide a medium that not only would prevent ingrowth of extraneous material but would give controlled, ac celerated growth of the neurons them selves. We now have been able to make surfaces that will separate neurons from glia [neural support tissue] and grow one or the other. We have gotten to the point that they now will attach to the surface and keep growing, where before they lifted off in a couple of days and stopped growing." Lyman emphasizes, however, that results so far are "extremely pre liminary." "We make all our own materials," Lyman says, "and we try to design them molecularly to do what we want." One class of materials that seems to have tre mendous promise is the copolyurethanes. Block copolymers allow tremendous variations of properties, even with the same molecular structure. Lyman also stresses the center's com mitment to basic research. "We're trying not only to build specific implants, but to build them on the basis of the very fun damental knowledge we're acquiring. That way, everything we learn accelerates the next implant. " α
