| Περίληψη: | Increasing morbidity of cardiovascular diseases in modern society has made it crucial to develop small caliber arterial grafts, as alternatives to the gold standard autologous implants, to replace diseased coronary arteries. Synthetic small caliber grafts are still not in use due to increased risk of restenosis, lack of lumen re-endothelialization and mechanical mismatch, leading sometimes either to graft failure or to unsuccessful remodeling and pathology of the distal parts of the anastomosed healthy vascular tissues.
In this work, we aimed to synthesize small caliber polymeric (polycaprolactone) tissue-engineered vascular scaffolds that mimic the structure and biomechanics of natural vessels. Electrospinning was implemented to prepare micro structured polymeric membranes with controlled parallel fiber alignment. Consequently, we designed small caliber multilayer anisotropic biodegradable nanofibrous tubular scaffolds, giving attention to their radial compliance.
Polycaprolactone scaffold morphology and mechanical properties were assessed, quantified and compared with those of native vessels and commercial synthetic grafts. Results showed a highly hydrophobic scaffold material with a 3-layered tubular morphology, 4 mm internal diameter/0.25 ± 0.09 mm thickness, consisting of predominantly axially aligned thin (1.156 ± 0.447 um), homogeneous and continuous microfibers, with adequate (17.702 ± 5.369 um) pore size. Mechanical anisotropy was attained as a result, almost one order of magnitude difference for the elastic modulus (18±3 MPa axially/1±0.3 MPa circumferentially), similar to that of natural arterial walls. Furthermore, a desirable (physiological) radial compliance (5.04±0.82%, within the physiological pressure range) as well as cyclic stability of the tubular scaffold were achieved.
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