Enhanced biocompatibility of poly(l‑lactide‑co‑epsilon‑caprolactone) electrospun vascular grafts via self-assembly modification.

Thousands of coronary artery bypass surgeries are performed in the world every year. But there is still no alternative to autologous vessel transplantation yet. In the present study, we optimized the weight ratio of chitosan/poly(l‑lactide‑co‑epsilon‑caprolactone) (CS/PLCL) of the electrospun scaffolds, which lead to suitable mechanical properties, such as tensile strength, ultimate strain, elastic modulus and burst pressure. Besides, the scaffolds possessed the structure that mimics the native extracellular matrix. To improve the anticoagulant property of vascular grafts and avoid the use of toxic reagents, dextran sulfate was used to modify the scaffold by self-assembly method. The result of attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) demonstrated the successful modification of dextran sulfate on the scaffold. Simultaneously, modification with dextran sulfate enhanced the hydrophilicity of the scaffold. Then the degradation property of the scaffolds was evaluated by the pH value of the phosphate buffer solution (PBS) soaking solutions and mass loss of the scaffolds. Hemocompatibility test was then performed to determine the enhanced anticoagulation and antihemolysis properties of the modified scaffold. The in vitro cell viability results showed that the modified scaffold possessed favorable cell viability to the human vascular cells. Furthermore, the scaffolds were subcutaneously implanted in mice for 4 weeks. Compared to the unmodified and pure PLCL tubular scaffolds, the histological analysis indicated that the modified tubular scaffolds possessed low inflammatory response and more infiltrated cells in the scaffold. Therefore, our studies showed that dextran sulfate modified scaffold might pave the way to fabricate small-diameter vascular grafts for clinical application.