Fabrication of permeable tubular constructs from chemically modified chitosan with enhanced antithrombogenic property

Abstract

The failure of artificial vascular grafts in small diameter vessel replacement is mainly due to the early formation of thrombosis. To prevent the occurrence of thrombosis, much effort has been focused on developing an anti-thrombogenic coating of synthetic vascular prostheses or artificial conduits with improved anti-thrombogenic properties. Because surface coatings may be unstable for long-term applications, a bulk material with anti-thrombogenic property is desirable for the fabrication of vascular grafts or conduits. To this end, we have chemically modified chitosan by phthalization to derive an anti-thrombogenic material for the fabrication of vascular grafts. The chemical structure of phthalized chitosan was characterized with infrared spectroscopy. The hydrophilicity was examined with contact angle measurement, and the molecular weight distribution was measured using gel permeation chromatography (GPC). Protein adsorption, hemolysis, and platelet adhesion assays were used to confirm the enhanced anti-thrombogenic properties of this phthalized chitosan. Cytotoxicity and proliferation assays were performed to test its high biocompatibility. With its improved solubility and processibility, this phthalized chitosan was fabricated into selective permeable tubular constructs of varying sizes and morphology through a wet phase-inversion process. With improved anti-thrombogenic property, biocompatibility, and great processibility, phthalized chitosan has great potential as the material for the fabrication of small diameter vascular grafts.

Hemocompatibility evaluation of small elastomeric hollow fiber membranes as vascular substitutes

“…For example, Qiu et al modified chitosan with phthalate groups to increase its antithrombogenic properties for the development of small vascular grafts. 13 More recently, Wu et al coated a small polyglycerol sebacate (PGS) graft with heparin and successfully used it to restore function in a rat abdominal aorta model. 14 In our lab, we have developed and characterized elastomeric polyester urethane (PEU)-based hollow fiber membranes (HFMs) as candidates for SDVG.…”

Chitosan-PLGA polymer blends as coatings for hydroxyapatite nanoparticles and their effect on antimicrobial properties, osteoconductivity and regeneration of osseous tissues

“…It can also induce thrombosis [32], and this is what makes the material improper for wider use. There are different strategies for increasing hemocompatibility of chitosan and they are chiefly directed at its chemical modification or mixing with other compounds which exhibit complementary features [33]. HAp particles combined with chitosan, a bioderived polymer, have produced a large interest in bone tissue engineering community because of a generally positive biological response thereto [34,35].…”

Development and evaluation of elastomeric hollow fiber membranes as small diameter vascular graft substitutes

“…Polymers as a group offer significant versatility in vascular graft design due to their ease of customization and flexibility. Polylactic acid (PLA) [13], polycaprolactone (PCL) [14, 15], poly(D,L-lactide- co -glycolide) (PLGA) [24], poly(glycerol sebacate) (PGS) [23, 30], polyimides [17, 18, 20], polyurethanes [10, 26, 29], and other polymers [19, 21] have been used successfully for the fabrication of candidate SDVGs. These SDVGs have also shown encouraging results.…”