Challenging issues in manufacturing bioresorbable scaffolds for clinical tissue engineering applications

Abstract: The concept of tissue engineering arises from the need to develop an alternative method of treating patients suffering from tissue loss or organ failure. Current therapies in use today are not only expensive but often do not adequately fulfill their intended purpose. In standard organ transplantation, a mismatch of tissue types necessitates lifelong immunosuppression, with its attendant problems of graft rejection, drug therapy costs, and the potential for the development of cancer. Even when one's own tissues are used, the types of tissues available for reconstruction or transplantation are often unsuitable. In all such circumstances, surgical invasion of another part of the body leaves a patient in pain, in jeopardy of functional losses at the donor site, and in need of additional care. These problems will be solved only when human tissues can be patient specifically designed and grown - a prospect that is closer to reality than most surgeons realize. Tissue engineering is a truly multidisciplinary field which applies the principles of engineering, life science, and basic science to the development of viable substitutes which restore, maintain, or improve the function of human tissues. Tissue engineering techniques generally require the use of a porous bioresorbable scaffold, which serves as a three-dimensional template for initial cell attachment and subsequent tissue formation both in vitro and in vivo. The biodegrdability or bioresobility of the scaffold allows it to be gradually replaced by new cells to form functional tissues.  Ideally, a scaffold should have the following characteristics: (i) highly porous with interconnected pore network for cell growth and flow transport of nutrients and metabolic waste, (ii) biocompatible and bioresorbable with controllable degradation and resorption rate to match tissue replacement, (iii) suitable surface chemistry for cell attachment, proliferation, and differentiation, (iv) mechanical properties to match those of the tissues at the site of implantation, (v) be reproducible processed into variety of shapes and sizes by solid free form fabrication  The present presentation looks into the challenging issues in manufacturing bioresorbable scaffolds for clinical tissue engineering applications for bone and cardiovascular applications.