Biomaterials in the 21st century?

When asked by our Editor to write a guest edhohal on Biomaterials for this issue, I began to look for a theme that would crystallize my thoughts . The 21st century is less than 5 years away . That is approximately the time scale of many research projects sponsored by the VA Rehabilitation Research and Development Service . Thus, I face the same challenge that researchers do in trying to develop new or improve already existing materials in the quest for improving our quality of health, extending life spans, or freeing us from pain—where do we go from here? At present, the biomaterials scientist has the entire gamut of appropriate materials to choose fromn—mnota!o, alloys, ceramics, polymers, composites—the choice being predicated on a number of factors : location, function, compatibility, availability . Of course, always in mind is the duol concern—the material(s) do not act inimically on the body and vice versa, the body does not affect the material(s) inimically . Thus, we now have joint implants made of various combinations of metals or composites used with ceramics andlor polymers to restore function when it is lost due to accident or pathology ; the metals and composites providing the appropriate stiffness and rigidity to support loads ; the ceramics and polymers providing low friction surfaces for joint movement . We have sight and sound restored in many instances by the use of biomaterials. Where function involves some sort of stimulus, as in pacemakers or cochlear implants, the electrical systems and the leads must be properly encapsulated in biocompatible materials able to withstand the body's inimical environment for long periods of time . It is similar for synthetic heart valves and vascular replacements . Artifiuial skin combining synthetic materials with the naturally occurring biopolymer, collagen, saves the lives of burn patients. Many drugs, whose use is required for a specific target (e .g . ' pills for birth control or nitroglycerin tablets for angina), are taken systemically, which means larger doses than might be required on site. Externul patches over the heart, which release small amounts of the drug continuously, keep the condition under control . Implantable time-release systems in situ for birth oon1nol mean significantly lower dosages J. Lawrence Katz, Ph .D. Professor of Biomedical Engineering Case Western Reserve University Cleveland, OH