title: On the binding of complement to solid artificial surfaces in vitro.
abstract: Since the realization of a complement activation capacity by artificial surfaces upon contact with blood, a common belief has evolved that charged nucleophilic surface groups such as amine (-NH2) and hydroxyl (-OH) react with and eventually bind to the internal thioester in complement factor 3 (C3). A covalent amide or ester linkage is thereby supposed to form between C3b and the surface itself. In this report, we present complement surface binding data by null-ellipsometry for two nucleophilic surfaces (-NH2 and -OH), for surfaces with immunoglobulin G (IgG) covalently bound, and for IgG spontaneously pre-adsorbed to hydrophobic silicon. The results reveal that the plasma proteins that were deposited during complement activation became eluted by sodium dodecyl sulfate. Hence the direct covalent binding between C3 and solid nucleophilic surfaces seems to be only of moderate importance, at least during shorter serum incubations. This strongly suggests that the prevalent covalent linkage model between solid artificial surfaces and C3b is not accurate. Instead we suggest a more pronounced role for C3 associations to other adsorbed proteins and or electrostatic and hydrophobic protein-surface interactions.
authors.affiliation: Department of Physics and Measurement Technology, Linköping University, Sweden. jonwe@ifm.liu.se
authors.forename: Jonas
authors.initials: J
authors.lastname: Wetterö
authors.forename: Agneta
authors.initials: A
authors.lastname: Askendal
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Bengtsson
authors.forename: Pentti
authors.initials: P
authors.lastname: Tengvall
mesh_terms: D000327:Adsorption; D001672:Biocompatible Materials; D003167:Complement Activation; D003176:Complement C3 / Q000378:metabolism; D003165:Complement System Proteins / Q000378:metabolism*; D005990:Glycerol / Q000031:analogs & derivatives*; D006046:Gold; D006801:Humans; D007074:Immunoglobulin G; D066298:In Vitro Techniques; D008422:Materials Testing; D011485:Protein Binding; D055672:Static Electricity; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D003176:Complement C3; D007074:Immunoglobulin G; D006046:Gold; D003165:Complement System Proteins; C009465:thioglycerol; D005990:Glycerol