Biomedical polymers

Publisher Summary This chapter focuses on the polymers that are biocompatible, that is, those that are not toxic to the body on implantation, can be classified as being bioinert or bioresorbable. Generally, high molecular weight biocompatible polymers are non-degradable and are classed as bioinert. Toxicity can occur with normally biocompatible polymers due to leaching of low molecular weight plasticizers and additives. It is important to characterize the grade of polymer in use. What is sold as polymer X by one manufacturer may be very different from polymer X sold by another, due to the purity and additives present. Surface reactions and absorption of proteins at the polymer surface can also cause problems. Therefore, the surface texture and the shape of the implant are also important. Bioinert polymers, such as polyethylene and polymethylmethacrylate are used in joint replacements and are designed to remain in place, unchanged for many years. Polyethylene has been used in composites such as HAPEX®;, which has been used as middle ear prostheses. Polyesters, such as polyglycolic and polylactic acids, are used as resorbable polymers in applications, such as dissolving sutures. Resorbable polymers are also being investigated for use as scaffolds for tissue engineering applications.