Electrospinning of Biomaterials for Vascular Regeneration

Nanomaterials for small diameter vascular grafts: overview and outlook

Small-diameter vascular grafts (SDVGs) cannot meet current clinical demands owing to their suboptimal long-term patency rate. Various materials have been employed to address this issue, including nanomaterials (NMs), which have demonstrated exceptional capabilities and promising application potentials. In this review, the utilization of NMs in different forms, including nanoparticles, nanofibers, and nanofilms, in the SDVG field is discussed, and future perspectives for the development of NM-loading SDVGs are highlighted. It is expected that this review will provide helpful information to scholars in the innovative interdiscipline of cardiovascular disease treatment and NM.

Surface Functionalization of Electrospun Scaffolds by QK-AG73 Peptide for Enhanced Interaction with Vascular Endothelial Cells

Rapid endothelialization still remains challenging for blood-contacting biomaterials, especially for long-term, functional, small-diameter vascular grafts. The vascular endothelial growth factor (VEGF)-mimicking QK peptide holds great promise in promoting vascular endothelial cellular activities such as adhesion, spreading, proliferation, and migration. Syndecans are transmembrane proteoglycans that are highly expressed on cell surfaces, including vascular endothelial cells, which can act as docking receptors to provide binding sites for a variety of cellular growth and signaling molecules. Herein, a novel peptide QK-AG73 that coupled the QK domain with the syndecan binding peptide AG73 was proposed, aiming to synergistically enhance the interaction with vascular endothelial cells. In addition, mechanically matched bioactive scaffolds based on poly(l-lactide-co-ε-caprolactone) were successfully prepared by surface functionalization of the covalently combined QK-AG73 peptide. The result showed that the adhesion of human umbilical vein endothelial cells (HUVECs) was increased by approximately 2-fold on QK-AG73-modified surface compared with those modified with a single QK or AG73 peptide. Moreover, surface functionalization of electrospun scaffolds by this QK-AG73 peptide was more efficient in specifically promoting the proliferation of HUVECs and allowing them to grow with an elongated cobblestone-like cell morphology. It was hypothesized that both VEGF receptors and transmembrane syndecan receptors were involved in cellular regulation by the QK-AG73 peptide, which resulted in synergistic improvement of the interactions with vascular endothelial cells and provided a promising strategy to promote endothelialization of small-diameter vascular grafts.

Electrospun membranes of carboxylated poly(ester urethane)urea/gelatin encapsulating pterostilbene for adaptive and antioxidative purposes

Oxidative stress caused by the harsh microenvironment after implantation of an artificial graft with mismatching mechanical properties usually triggers inflammation responses, which have adverse impacts on tissue regeneration. For coping with these problems, in this work, bioactive fibrous scaffolds were developed from specially synthesized carboxylated poly(ester urethane)urea (PEUU) and gelatin (Gel) by encapsulating pterostilbene (Pte) for the first time. The prepared electrospun membranes exhibited self-adaptable mechanical properties with high elasticity owing to the bonded electrospun fibers, cross-linking network between PEUU and Gel, and the inherent flexibility of the PEUU polymer in the fibrous matrix. The PEUU/Gel/Pte electrospun membrane containing 7% Pte could promote in vitro proliferation of human umbilical vein endothelial cells, and regulate vascular smooth muscle cells with excellent antioxidant properties via free radical scavenging. In vivo results in a rat subcutaneous implantation model further demonstrated the positive effect of the specially prepared PEUU/Gel/Pte scaffold on both normal cell growth and anti-inflammatory by promoting cellularization and polarizing macrophages toward the M2 phenotype. These PEUU/Gel/Pte electrospun membranes with adaptability benefit to tissue regeneration by modulating inflammation responses, especially applications in vascular regeneration.

PBAT/gelatin hybrid nanofibers based on post-double network bond processing as a promising vascular substitute

The development of injured vascular tissue substitutes with proangiogenic, anti-thrombus, and anti-hyperplasia activity still remains a major challenge in vascular tissue engineering. In this study, we have prepared a series of poly(butylene adipate-co-terephthalate)/gelatin hybrid nanofibers (P/G) through random electrospinning and post-double network bond crosslinking for process optimization according to physiochemical and mechanical properties as well as promoting enhanced vascular cell viability in vitro. The gelatin matrix was shown to be successfully contained in the bicomponent hybrid P/G nanofibers, and the formed P/G nanofibers exhibited a uniform and smooth morphology. Importantly, the bicomponent hybrid nanofibers showed a potentially reliable ability to promote the proliferation of human umbilical vein endothelial cells (HUVECs). In addition, all the results demonstrated the significantly stable microstructure, appropriate surface wettability, matched mechanical properties, and excellent blood compatibility, cellular compatibility, and histocompatibility of hybrid nanofibers containing 15 wt% gelation (P/G-15) compared to PG-0, P/G-5, and PG-25 groups, indicating their potential for vascular injury healing.

A PBAT/gelatin hybrid nanofibers vascular graft containing 15 wt% gelation (P/G-15) exhibited matched mechanical properties, especially they demonstrate excellent blood compatibility, cellular compatibility, and histocompatibility in rabbit carotid artery model.