Electrospun biodegradable materials for vascular regenerative medicine

Objectives: There is a rising interest for the development of small-sized blood vessels substitutes. Several studies have been focused on the development of a biodegradable graft temporarily able to substitute the blood vessels and allow their complete regeneration after a certain time. We tried to develop a biodegradable material, with optimal mechanical characteristics and the capacity to allow cells adhesion, differentiation and proliferation by electrospinning to obtain a nano-fibrillar scaffold starting from a polymeric solution. Methods: We report the in vivo application on rats of two new electrospun biodegradable materials, specifically designed to create tubular structures. Both biomaterials can be functionalized with several polypeptidic and nonpolypeptidic active molecules (growth factors or drugs). In one case PHEA-PLA was co-spun with silk fibroin (Fibro-PHEA-PLA) by a parallel electrospinning process to obtain a scaffold with two different polymeric fibers. In the other case, PHEA-PLA was mixed with polycaprolactone (PCL-PHEA-PLA) to obtain a single spinning solution for the obtainment of hybrid fibers scaffold. The in vitro assay showed colonization by fibroblasts in both materials. The scaffolds were implanted in a dorsal fascial pouch on Winstar rats to evaluate their in vivo biocompatibility and tissue integration. The scaffolds were removed at 7, 15 and 40 days after implantation. Results: The pathological findings showed that both materials were totally absorbed after 40 days without any sign of inflammation. A neutrophilic reaction was predominant at 7 days, especially for PCL-PHEA-PLA alone, whereas a lymphocytic invasion was showed at 15. At 15 days Fibro-PHEA-PLA showed a good cell adhesion with a low grade of inflammation. Cell adhesion was confirmed at SEM scan. Conclusions: This preliminary study showed a good biocompatibility property of the scaffolds that needs of further investigations. The capability of the materials to be functionalized, should allow us to guide the development of bioengineered vessels.