Number of blood vessels within 40 μm of implant surface after 2 weeks implantation in rat subcutaneous tissue. The implanted materials were bare PES fibers (PES, n = 9), hydrogel-coated PES fibers (GEL, n = 10), VEGF-releasing hydrogel-coated PES fibers (VEGF GEL, n = 10), DX-releasing hydrogel-coated PES fibers (DX GEL, n = 10), and VEGF + DX-releasing hydrogel-coated PES fibers (VEGF + DX GEL, n = 10). VEGF-releasing hydrogels were shown to have a significantly increased blood vessel count compared to VEGF-DX-releasing hydro-gel-coated, hydrogel-coated, and bare fibers (p < 0.05).