We used PCL, a hydrophobic highly biocompatible and biodegradable (FDA-approved) aliphatic polyester as the high-strength material of a multilaminate final design that can support the creation of a polymer-cell complex in vitro with subsequent implantation in vivo.
The current work is a pilot study toward the design of electrospun anisotropic biodegradable nanofibrous small-caliber polymeric VTE scaffolds that mimic the structure and biomechanics of natural blood vessels, giving emphasis to their radial compliance. Electrospun membranes made of polycaprolactone (PCL) and its composites are widely used in biomedical applications, especially as scaffolds in tissue-engineering applications and have been shown to possess excellent biomechanical features and structural similarity with the ECM of blood vessels. PCL chemically degrades due to hydrolytic cleavage of the back-bone ester bonds and thereby converting long polymer chains into shorter water-soluble fragments. The increasing need for surgical therapies of CVDs in the modern society has made it crucial, among others, to develop blood vessel substitutes especially for diseased small-caliber ones (2.5 years) in human body. In Europe, 3.9 million deaths annually (1.8 million in the EU alone) are owed to CVDs, while the total costs are calculated for the EU in 210 billion euros annually (2017 statistics). Finally, cytotoxicity evaluation of the polymeric scaffolds revealed that the materials were nontoxic and did not release substances harmful to living cells (over 80% cell viability achieved).Ĭardiovascular diseases (CVDs) are the main cause of death in industrialized countries and among the top three worldwide. Furthermore, a desirable radial compliance (5.04 ± 0.82%, within the physiological pressure range) as well as cyclic stability of the tubular scaffold was achieved. Mechanical anisotropy was attained as a result, almost one order of magnitude difference of the elastic modulus (18 ± 3 MPa axially/1 ± 0.3 MPa circumferentially), like that of natural arterial walls. In vitro accelerated degradation showed a 5% mass loss within 17–25 weeks. Results showed a highly hydrophobic scaffold material with a three-layered tubular morphology, 4-mm internal diameter/0.25 ± 0.09-mm thickness, consisting of predominantly axially aligned thin (1.156 ± 0.447 μm), homogeneous and continuous microfibers, with adequate (17.702 ± 5.369 μm) pore size, potentially able to promote cell infiltration in vivo. Polycaprolactone scaffold morphology and mechanical properties were assessed, quantified, and compared with those of native vessels and commercial synthetic grafts. Consequently, we designed small-caliber multilayer anisotropic biodegradable nanofibrous tubular scaffolds, giving attention to their radial compliance. Electrospinning was implemented to prepare microstructured polymeric membranes with controlled axis-parallel fiber alignment. In this work, we aimed to synthesize small-caliber polymeric (polycaprolactone) tissue-engineered vascular scaffolds that mimic the structure and biomechanics of natural vessels. 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. Increasing morbidity of cardiovascular diseases in modern society has made it crucial to develop artificial small-caliber cardiovascular grafts for surgical intervention of diseased natural arteries, as alternatives to the gold standard autologous implants.
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