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The present chapter is concerned with the electrochemical characterization of biomedical polymers. Together with such properties as the relative hydrophobicity/hydrophilicity and the chemical composition of the surface, the presence of electrical charges is an important additional feature, determining the suitability of materials for artificial implants, dialysis or perfusion membrane supports, and other medical applications.

In this highly complex interdisciplinary area of biomedical polymers, progress is beginning to be made in a variety of implants. Of probable major importance is that of small diameter blood vessel repair. The studies leading to the development of a small diameter vascular graft are discussed to show the interrelationship between polymer surface and bulk morphology, polymer-protein interaction, platelet adhesion, and implant mechanical properties on the performance of the implant in the body.

During this last decade we have seen not only a large increase in the number of polymers being examined for biomedical uses, but more significantly, a great change in how these materials were characterized. Luckily, we no longer see papers in which, for example, the author simply said, “a plastic was implanted”; and we are seeing less data simply being reported as gross observations only.

The surface characterization of biomedical materials prior to the early 1960’s consisted primarily of relatively qualitative observations as to whether surfaces were hydrophobic or hydrophilic (1). Contact angle techniques were well-known and were widely applied in industry, and general correlations had evolved between blood interactions in glass as opposed to siliconized glass tubes. Vroman was just beginning his studies on protein interactions with surfaces (2). There was considerable interest during this time period on the interaction of cells in culture with solid substrates, and there was some attempt to correlate and quantitate that interaction through contact angle measurements (3).

Of major concern in the development of polymers for medication is the question of the biocompatibility of the polymeric system. We have investigated the biocompatibility of various polymers from the inflammatory response perspective utilizing an in vivo cage system. This cage system permits the quantitive determination of various components of the inflammatory response. Quanitative assays will be presented which can be used to determine the temporal variations in cell function in the inflammatory exudate that interacts with the implanted biomedical polymers or drug-polymer delivery systems. In addition, correlative, comparative, and quantitative information on the release characteristics and cellular response, adhesion and activation, that is the biocompatibility, of polymeric systems also will be presented.

The field of biomedical polymers continues to show steady growth in both the basic research and applications areas. The only limit to the suggested uses of polymers in medicine seems to be a limit in our imagination. Some recent popular articles suggest that nearly all parts of the human body could be replaced by some type of a plastic and/or metal device (1,2). Many major problems remain to be solved before this vision could become fact, however. A large number of recent surveys and books attest to the great interest in this important field of science (3–31). These books but scratch the surface and hundreds of articles are published each year in a variety of journals including such specialized ones as the Journal of Biomedical Materials Research and the Transactions of the American Society of Artificial Internal Organs. Courses in the field of biomedical polymers and biomaterials are now offered at many different universities (32).