Anticoagulant Hydrogel Tubes with Poly(ɛ‐Caprolactone) Sheaths for Small‐Diameter Vascular Grafts

Abstract

Small-diameter vascular grafts (inner diameter < 6 mm) are useful in treating cardiovascular diseases. The off-the-shelf small-diameter vascular grafts for clinical applications remain a great limitation owing to their thrombogenicity or intimal hyperplasia. Herein, bilayer anticoagulant hydrogel tubes with poly( -caprolactone) (PCL) sheaths are prepared by freeze-thawing and electrospinning, which contain nanofibrillated cellulose (NFC)/poly(vinyl alcohol) (PVA)-heparin/poly-L-lysine nanoparticles tube as an inner layer and PCL sheath as an outer layer. The structure, anticoagulant property, and biocompatibility of the inner layer are studied. The effects of thickness of the outer layer on perfusion performance and mechanical property of hydrogel tubes with PCL sheaths (PCL-NFC/PVA-NPs tubes) are investigated. The effect of compliance of PCL-NFC/PVA-NPs tubes on their blood flow is studied by numerical simulation. The tissue compatibility and the patency of PCL-NFC/PVA-NPs tubes are evaluated by implantation in subcutaneous tissue of rats and carotid artery of rabbits. PCL-NFC/PVA-NPs tubes have prominent anticoagulation, sufficient burst pressure and good compliance similar to native arteries. PCL-NFC/PVA-NPs tubes facilitate infiltration of host cells and achieve active proliferation of recruited cells, which will be a promising candidate for small-diameter vascular grafts.

Review of Polymeric Biomimetic Small-Diameter Vascular Grafts to Tackle Intimal Hyperplasia

“… 173 It has been reported that PVA demonstrated low platelet adhesion and low thrombin generation time. 174 However, PVA hydrogel for a vascular graft showed that the modified PVA with fibronectin, RGDS peptide, cyclicRGD (cRGD) peptide, and heparin showed platelet adhesion similar to that of ePTFE and unmodified PVA. However, the modified PVA had an increased endothelial cell proliferation.…”

“…However, the modified PVA had an increased endothelial cell proliferation. 174 Endothelialization of PVA surfaces is a major limitation and can be overcome by modifying biochemical and topographical cues to improve its bioactivity without compromising hemocompatibility. Polypeptides such as fibronectin, peptide (RGDS and cRGD), and lysine, as well as the anticoagulant heparin may be used for this purpose.…”

A versatile strategy to construct free-standing multi-furcated vessels and a complicated vascular network in heterogeneous porous scaffolds via combination of 3D printing and stimuli-responsive hydrogels

“…Inflammation and foreign-body responses of MFVs were investigated via subcutaneous implantation. 68,69 After 5, 10 and 30 days of implantation, the implanted MFV was removed out and used for hematoxylin and eosin (H&E) staining and histological analysis (CD 68 staining) (Fig. 5b).…”

Biocompatible Synthetic Polymers for Tissue Engineering Purposes

“…PVA is however a mechanically weak polymer. The mechanical properties of PVA can be strengthened with the addition of nanocellulose, , while its bioactivity can be improved by the incorporation of natural polymers or bioceramics. − …”

“…PCL is the dominating polymer among the newer scaffolds that are explored for the regeneration of vessels ,,,,− and is preferred because of its mechanical properties (ductility), suturability, and absence of graft dilation. To compensate for its slow degradation rate, it is combined with other polymers.…”