The importance of drug delivery systems in tissue engineering.

Tissue engineering is designed to regenerate natural tissues or to create biological substitutes for defective or lost tissues and organs through the use of cells. In addition to cells and their scaffolds, growth factors are required to promote tissue regeneration. Indeed, growth factor-induced vascularization is effective in supplying the oxygen and nutrients necessary for the survival of transplanted cells in organ substitution. However, growth factors have poor in vivo stability and so the biological effects are often unpredictable unless the delivery system is contrived. This review provides several examples to emphasize the importance of drug delivery systems in tissue engineering.