ABSTRACT
Transplantation of organs or tissues is a widely accepted therapy to treat patients with damaged organs or tissues as a result of an accident, trauma, cancer or disease. However, autologous transplantation is limited because of donor site morbidity and infection or pain to patients because of secondary surgery. Alternative tissue sources that have origins from other humans remain problematic mainly due to immunogenic responses by the patients upon implantation and a shortage of donor organs. Each year, millions of people die still due to shortage of organs to transplantation. Tissue engineering, which applies methods from engineering and life sciences to create artificial constructs to direct tissue regeneration, has attracted many scientists, surgeons with hope to treat patients in a minimally invasive and less painful way. The aim of tissue engineering, with an interdisciplinary approach, is to break through the barriers which have limited the performance and application of artificial biomaterials over past decades. The research examinations lead to develop, design and synthesize novel multi-component structures, using biocompatible and biodegradable natural/synthetic polymers with/without bioactive molecules that may be used as efficient scaffolds for engineering tissue. For this ambitious purpose mainly collagen, poly(lactic-coglycolic acid) (PLGA), cellulose and glycosaminoglycans (GAG) such as hyaluronic acid (HA) and chondroitin sulfate (CS), which have different physicochemical properties and degrade at different rates in human body have been used. The components of scaffolds are cross-linked/grafted by chemical, physical, and radiation methods. These scaffolds mimic closely the molecular and structural properties of native extracellular matrix (ECM). This review focuses on the progress in using some of the scaffolds for the specific regeneration of tissues. Among it, an advanced tissue engineering of collagen based materials for therapeutic treatment of injuries to central and peripheral nervous systems is presented
SOME ASPECTS OF TISSUE ENGINEERING
Tissue engineering applies scientific principles to the development, design, and construction of biological substitutes that restore, maintain, and improve natural tissue or organ function (Morrison, 2009). Its scientific input is derived from materials science, cell biology, physics, chemistry, and importantly, from clinical research. Restoration of the normal tissue structure and function occurs through the production of new tissue with replicates exactly that which has been lost as a result of degenerative disease, cancer, an accident or trauma. The restorative process depends on a balanced combination of cell culture growth with biomaterial/scaffold to support it and with bioactive
agents to enhance and direct it (Jagur-Grodzinski, 2006). There are several approaches to creating tissue constructs. A well known one is to isolate specific cells through a small biopsy from the patient, to grow them on a three dimensional (3D) biomimetic scaffold, under precisely controlled culture conditions and to deliver the construct to the appropriate site in the patient’s body, and to direct new tissue formation into the scaffold that would itself disappear, in due course, through biodegradation.
