Biodegradable polymers and composites in biomedical applications: from catgut to tissue engineering. Part 2 Systems for temporary replacement and advanced tissue regeneration

During the past century, and particularly in the past three decades, the application of conventional materials technology has resulted in clear advances in substitution medicine. For example, the development of artificialhips and knees have brought enormous benefits to patients. However, there are still no materials available that can adequately replace or aid the regeneration of functional tissues such as bones or large bone segments. In an increasingly aging population, malfunction or loss of tissue from injury or disease has led to reduced quality of life for many patients at significant socio-economic cost. There is thus demand for the development of new therapies through a multidisciplinary, biology driven approach in which biological tissues are engineered using both materials and bio-technologies. Tissue engineering has created a new field of application for biodegradable polymers, paving the way for the development of new classes of biomaterials from synthetic or natural origin and for the design of new materials formats for hybrid tissues. A general overview is provided of the main applications of biodegradable polymers in medicine, with particular emphasis on tissue engineering. The approaches available to tissue engineers and the requirements scaffold materials must fulfil to promote adequate interaction with cells and tissues are described; predictable trends and future developments are discussed. Processing routes for biodegradable polymeric scaffolds are also considered, presenting examples of three-dimensional materials fabricated by different methodologies.