Colloidal Protein Solutions as a New Standard Sensor for Adhesive Wettability Measurements

Wetting experiments are carried out for the investigation of the interfacial interactions that take place when various solid materials are in contact with protein colloidal solutions. These materials are chosen because they are widely used in the field of orthopedic surgery. Contact angles (sessile drop) and surface tension (du Nouy's ring method) are measured in standardized conditions which take into account the various parameters disturbing wetting phenomena. An original cumulative deposits method (CDM) described here permits observation of the evolution of the wettability and allows estimation of the protein adhesion rate. Two families of materials emerge according to their behavior when they are in contact with the protein solution. One set (a chromium cobalt alloy and two polyethylenes) presents no detectable adhesion. The other set (stainless steel, zirconia, alumina, virgin and nitrogen implanted titanium alloy) shows a cumulative adhesion of proteins. We propose to adopt a BSA buffered solution as a referential sensor to characterize solid surfaces. From the CDM, the practical parameter P*, called the adhesive wettability power, can be used in order to analyze and classify biomaterials. Copyright 1999 Academic Press.