STRATEGY FOR IN-VITRO EVALUATION OF THE INTERACTIONS BETWEEN BIOMATERIALS AND COMPLEMENT-SYSTEM

Because of the importance of complement activation in the induced activation of leukocytes in vivo, determination of the complement-activating capacity of a candidate biomaterial is an important step in evaluating its biocompatibility. In vitro evaluation can be performed in the presence of human serum by means of techniques described in the literature and reviewed in this paper. Certain physical and chemical parameters involved in complement activation by materials have to be assessed: the chemical composition of the surface, surface area in contact with serum, temperature and duration of contact, and ionic environment with emphasis on divalent ions. Concerning materials evaluation, the adsorption of complement proteins or protein fragments has to be determined in addition to activation. Following screening tests using CH50 determination, activation of both classical and alternative pathways leading to formation of C3 convertases and formation of C5 convertase should be assessed. An example of the determination of the complement-activating capacity of two hydroxylated materials is presented and guidelines for in vitro evaluation are proposed. (C) 1993 John Wiley & Sons, Inc.