ABSTRACT
Polymers ........................................................................................ 19 2.3 Bio-Hybrid Vascular Grafts Based on Elastin ............................... 23 2.4 Bio-Hybrid Vascular Graft Based on Collagen/Elastin/
Synthetic Polymers ........................................................................ 25 2.5 Bio-Hybrid Vascular Grafts Based on Gelatin/Synthetic
Polymers ........................................................................................ 26 2.6 Bio-Hybrid Vascular Grafts Based on Fibrin/Fibrinogen .............. 30 2.7 Bio-Hybrid Vascular Grafts Based on Bacterial Cellulose ............ 32 2.8 Bio-Hybrid Vascular Graft Based on Silk Fibroin/Synthetic
Polymers ........................................................................................ 34 2.9 Multi-Layered Bio-Hybrid Vascular Grafts ................................... 37 2.10 Summary ........................................................................................ 38 2.11 Acknowledgments ......................................................................... 40 Keywords ................................................................................................ 41 References ............................................................................................... 41
2.1 INTRODUCTION
Cardiovascular disease (CVD) remains one of the leading causes of death around the world [1]. This global health concern has prompted advances in surgical and medical technologies. However, an increasing percentage of the population continues to be at risk and eventually fall victim to this debilitating disease. While the most common cause of blood vessel failure in this case, is atherosclerosis, whereby plaque buildup within the lumen results in hindered blood flow, injury, disease, or inflammation can also result in a compromised vessel [2]. Routinely, a comparable native vessel (ex. internal thoracic arteries, radial arteries, and saphenous veins) will be excised and relocated to replace the occluded vessel in a procedure known as a coronary artery bypass graft (CABG) surgery. These autologous grafts have limited availability and depend on donor site morbidity [3]. For example, with close to a half a million coronary artery bypass operations performed annually in the US alone, more than 20% of the patients do not possess healthy graft veins for CABG [4]. Addressing this concern, researchers have increasingly looked towards scaffold-based vascular tissue engineering to produce readily available vascular grafts [5]. While synthetic polymers such as polyester (Dacron) or expanded poly tetra flourethylene (e-PTFE) have been used successfully to fabricate large diameter (>6 mm) blood vessels [6], these materials have resulted in loss of vessel patency due to thrombosis in small diameter (<6 mm) applications [7]. Furthermore, as these synthetic vascular grafts will ultimately be implanted into the patient, the biocompatibility of component materials is an important factor for the future success of this technology. To this end, vascular tissue engineers have shown a general movement toward small diameter (<6 mm) scaffolding comprised of biopolymers, those that naturally exist within vascular tissue matrix as well as naturally occurring biomaterials.
