Hydrocolloids and Medicinal Chemistry Applications

From functioning as simple space-fillers, lubricants or protective coatings, to providing three-dimensional matrices for cell growth, to acting as the functional moiety in environmentally responsive ‘smart devices’, the range of applications of biopolymers in biomedicine is vast. Hydrogel-forming biopolymer systems have characteristics that are advantageous in a biological context in comparison with more conventional engineering materials that have been used to repair damaged or missing tissues, the capacity to permit molecular diffusion due to high water content being a prime example. In mechanical terms, gel-forming biopolymers more closely resemble soft tissue and so increasingly find application in soft tissue repair, an area of biomaterials science that has received limited attention until relatively recently. Aside from intrinsic physical properties, however, it is the fundamental chemistry of natural polymer systems that provides scope for some of the more ingenious applications of these materials to biomedical problems. For example, the capacity for certain biopolymers to form cross-linked gels under physiological conditions presents opportunities for minimally invasive routes to delivery of drug and or cell-loaded implants into the body. It is the purpose of this chapter to summarize some of the ways in which these materials are applied and to identify the contribution of the biopolymer in each example to the functionality of the system described.