The Role of Biodegradable
Tissue engineering is fundamentally described as the generation of three -dimensional (3D) artificial tissues. Its consequential task is to regenerate human tissue or to develop cell-based substitutes in order to restore, reconstruct or improve tissue functions. Proper processing of biological and mechanical functionality is monumental for tissue engineered structures, the ones which are not mainly sufficient enough yet. Acquiring the solution for this problem demands intensive researches and studies in every aspects and steps of TE. As a matter of fact, creating a functional tissue requires efficient growth of various types of cells on a 3D scaffolds and the bulk production of one cell seems not to be adequate. The principal function of a scaffold is to direct cell behavior such as migration, proliferation, differentiation, maintenance of phenotype, and apoptosis by facilitating sensing and responding to the environment via cell–matrix and cell–cell communications.
Therefore, having such abilities provides scaffolds seeded with a special type of cell as an important part of tissue engineering and regenerative medicine. The scaffold design and fabrication are major areas of biomaterial research, since biomaterial scaffold can create substrate within which cells are instructed to form a tissue or an organ in a highly controlled way. In this chapter, it is tried to provide an inclusive survey of biopolymers to be used as scaffolds for tissue engineering, fabrication methods and engineering challenges such as mass transfer and mechanical strength. In the proceeding, these factors are reviewed in vascular and nerve systems.
Scaffold design and fabrication are major areas of biomaterial research and they are also important areas for tissue engineering and regenerative medicine research. Scaffold provides the necessary support for cells to proliferate and maintain their differentiated functions, and its architecture defines the ultimate shape of a new organ. An ideal scaffold should possess the following characteristics to bring about the desired biological response the scaffold should possess inter-connecting pores of appropriate scale to favor tissue integration and vascularization, be made from material with controlled biodegradability or bio-resorb ability, appropriate surface chemistry to favor cellular attachment, differentiation and proliferation, possess adequate mechanical properties to match the intended site of implantation and handling, should not induce any adverse response and, be easily fabricated into a variety of shapes and sizes.
Due to control scaffold degradation and mechanical integrity, cell-scaffold interaction as well as cell function, one must have access to a range of materials. Therefore, an appropriate fabrication method is required with which it is possible to have a structure with different independent parameters and materials. It is worth to mention that degradation of synthetic polymers, both in vitro and in vivo conditions, releases by-products. For example, for PLLA releasing Lactic acid during degradation, causes reducing the pH, which further accelerate the degradation rate due to autocatalysis which later affects cellular function. In addition to degradation rate and by-products, certain physical characteristics of the scaffolds must be considered when designing a substrate to be used in tissue engineering applications.
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Journal of Biochemistry & Biotechnology