جایگزین های بافت نرم Soft Tissue Replacements

Soft Tissue Replacements

جایگزین های بافت نرم 

ABSTRACT

Blood comes in contact with foreign materials for a short term in extracorporeal devices such as dialyzers , blood oxygenators , ventricular assist devices, and catheters . Long-term vascular implants include heart valve prostheses, vascular grafts , and cardiac pacemakers , among others. In this section, we will be concerned with development of biomaterials for long-term implants, specifically for heart valve prostheses, total artificial heart ( TAH ), and vascular grafts. The primary requirements for biomaterials for long-term implants are biocompatibility, nontoxicity, and durability. Furthermore, the material should be nonirritating to the tissue, resistant to platelet and thrombus deposition, nondegradable in the physiological environment, and neither absorb blood constituents nor release foreign substances into the blood stream [Shim and Lenker, 1988]. In addition, design considerations include that the implant should mimic the function of the organ that it replaces without interfering with the surrounding anatomical structures and must be of suitable size and weight. The biomaterials chosen must be easily available, inexpensive, easily machinable, and sterilizable and have a long storage life.