Лако-красочные материалы — производство

Various techniques have been designed to study the strength of adhesion between biolo­gical substrates and water-soluble or water-insoluble polymers. Adhesive quantitation of water-insoluble polymers usually involves measurement of tensile and shear strength of adhesion. In an appropriate buffer solution, the polymer is sandwiched between either two biological membranes or a membrane and a nonbiological substrate, and the detachment force is measured. Using a modified tensiometer, the tensile strength can be measured from the vertical force of detachment [18,26] and the shear strength can be measured from the horizontal force of detachment [26]. When measured under controlled conditions of con­stant surface area, rate of removal, and applied force, these two parameters can give a comparative measure of adhesive performance. These methods allow the selection of suitable tissues for adherence as well as control of the bathing medium. Although the preferred substrate for bioadhesion, the use of tissue samples can be costly, and thus other less expensive methods are sometimes sought. One such approach is to use red colloidal gold particles which form a conjugate with mucin [35]. Upon interaction with a polymer, the intensity of the red color of the conjugate-polymer can be measured spectrophotome — trically. Whereas the techniques discussed above measure adhesion strength, this method measures adhesion number.

Adhesive measurement of water-soluble polymers is more difficult, but a number of techniques have been reported to assess adhesive strength adequately. One method is to coat a plate of glass with a soluble polymer and, using a tensiometer, measure the force to move it through a mucus solution [17]. Fluorescent probes have also been used to measure bioadhesion of soluble polymers to cell membranes [22]. With this approach adhesive strength is measured as a function of membrane viscosity differences before and after polymer binding using the fluorescent probe pyrene, which is incorporated into the lipid bilayer. Others have described methods on the static and dynamic adhesiveness of polymers in mucin solutions based on fluid mechanics [36]. More recently, researchers have studied bioadhesion by measuring viscometric differences in a mixture of polymer and gastric mucin [37].