Tissue engineering using synthetic biodegradable polymers

Chaignaud B E, Langer R and Vacanti J P, The history of tissue engineering using synthetic biodegradable polymer scaffolds and cells . In Synthetic Biodegradable... 

Wong W H and Mooney D J, Synthesis and properties of biodegradable polymers used as synthetic matrices for tissue engineering . In Synthetic Biodegradable Polymer Scaffolds, ed. A Atala, D J Mooney, J P Vacanti and R Langer, Birkhauser, Boston, USA, 1997, 51-82. 

In our laboratory, we use synthetic biodegradable polymers as templates to which cells adhere and are transplanted. The polymers act as a scaffolding which can be engineered to allow for implantation of transplanted cells within only a few cell layers from the capillaries, and thus allow for nutrition and gas exchange by diffusion until successful engraftment is achieved. In this manner, we hoped to generate permanent functional new tissues composed of donor cells and recipient interstitium and blood vessels. 

Linear Aliphatic Polyesters. Linear ahphatic polyesters are the most frequently used synthetic biodegradable polymers in tissue engineering and many other biomedical applications (26-28). These polymers degrade through hydrolysis of the ester bonds in the polymer backbone. The degradation rates and profiles differ between these polymers owing to their compositional, structural, and molecular weight differences. 

Saxena, A.K., Marler, J., Benvenuto, M., Willital, G.H., Vacanti, J.P., 1999. Skeletal muscle tissue engineering using isolated myoblasts on synthetic biodegradable polymers preliminary studies. Tissue Eng. 5, 525—532. 

Table 1.16 Physical Properties of Synthetic Biodegradable Polymers Used as Scaffolds in Tissue Engineering (Morita and Ikada, 2002, with permission from Marcel Dekker)... 

Solvent casting and particulate leaching (SC/PL) is a simple and commonly used method for fabricating scaffolds for tissue engineering. With an appropriate thermal treatment, porous constructs of synthetic biodegradable polymers can be prepared with specific porosity, surfaceivolume ratio, pore size and crystallinity for different applications. This method involves mixing water-soluble salt (e.g. sodium chloride, sodium citrate) particles into a polymer solution. The mixture is then cast into the mould of the desired shape. After the solvent is removed by evaporation or lyophilization, the salt particles are leached out to obtain a porous structure with the pore shape limited to the cubic crystal shape of the salt. Removal of soluble particles from the interior of a polymer matrix is difficult and limits the thickness of the films prepared to ca. 2 mm [293]. 

Numerous studies have investigated the efficiency of using composite scaffolds composed of CS and other biopolymer materials, such as collagen or synthetic biodegradable polymer materials, for cartilage tissue engineering [15]. 

---