Biomaterials for tissue engineering

Biomaterials play a critical role in the engineering of new functional geni tourinary tissues for the replacement of lost or malfunctioning tissues. Th ey provide a temporary scaffolding to guide new tissue growth and organizat ion and may provide bioactive signals (e.g., cell-adhesion peptides and gro wth factors) required for the retention of tissue-specific gene expression. A variety of biomaterials, which can be classified into three types - natu rally derived materials (e.g., collagen and alginate), acellular tissue mat rices (e.g., bladder submucosa and small-intestinal submucosa), and synthet ic polymers [e.g., polyglycolic acid, polylactic acid, and poly(lactic-co-g lycolic acid)] - have proved to be useful in the reconstruction of a number of genitourinary tissues in animal models. Some of these materials are cur rently being used clinically for genitourinary applications. Ultimately the development or selection of appropriate biomaterials may allow the enginee ring of multiple types of functional genitourinary tissues.