Collagen- vs. Gelatine-Based Biomaterials and Their Biocompatibility: Review and Perspectives

Abstract

Selection of a starting material, which will somehow mimic a naturally-existing one, is one\rof the most important points and crucial elements in biomaterials development. Material\rbiomimetism is one of those approaches, where restoration of an organ’s function is\rassumed to be obtained if the tissues themselves are imitated (Barrere et al., 2008). However,\rsome of the biopolymers as e.g collagen can be selected from within a group of biomimetic\rmaterials, since they already exist, and have particular functions in the human body.\rCollagen is one of the key structural proteins found in the extracellular matrices of many\rconnective tissues in mammals, making up about 25% to 35% of the whole-body protein\rcontent (Friess, 2000; Muyonga et al., 2004). Collagen is mostly found in fibrous tissues such\ras tendons, ligaments and skin (about one half of total body collagen), and is also abundant\rin corneas, cartilages, bones, blood vessels, the gut, and intervertebral discs (Brinckmann et\ral., 2005). It constitutes 1% to 2% of muscle tissue, and accounts for 6% of strong, tendinous\rmuscle-weight. Collagen is synthesized by fibroblasts, which originate from pluripotential\radventitial cells or reticulum cells. Up to date 29 collagen types have been identified and\rdescribed. Over 90% of the collagen in the body is of type I and is found in bones, skins,\rtendons, vascular, ligatures, and organs. However, in the human formation of scar tissue, as\ra result of age or injury, there is an alteration in the abundance of types I and III collagen, as\rwell as their proportion to one another (Cheng et al., 2011).\rCollagen is readily isolated and purified in large quantities, it has well-documented\rstructural, physical, chemical and immunological properties, is biodegradable,\rbiocompatible, non-cytotoxic, with an ability to support cellular growth, and can be\rprocessed into a variety of forms including cross-linked films, steps, sheets, beads, meshes,\rfibres, and sponges (Sinha & Trehan, 2003). Hence, collagen has already found considerable\rusage in clinical medicine over the past few years, such as injectable collagen for the\raugmentation of tissue defects, haemostasis, burn and wound dressings, hernia repair,\rbioprostetic heart valves, vascular grafts, a drug –delivery system, ocular surfaces, and\rnerve regeneration (Lee et al., 2001). However, certain properties of collagen have adversely\rinfluenced some of its usage: poor dimensional stability due to swelling in vivo; poor in\rvivo mechanical strength and low elasticity, the possibility of an antigenic response