Supercritical carbon dioxide generated vascular endothelial growth factor encapsulated poly(dl-lactic acid) scaffolds induce angiogenesis in vitro

The ability to deliver, over time, biologically active vascular endothelial growth factor-165 (VEGF) through tailored designed scaffolds offers tremendous therapeutic opportunities to tissue-engineered therapies. Porous biodegradable poly(dl-lactic) acid (PLA) scaffolds encapsulating VEGF have been generated using supercritical CO2 (scCO2) and the kinetic release and angiogenic activity of these scaffolds examined in vitro and in an ex vivo chick chorioallantoic membrane (CAM) angiogenesis model. After processing through scCO2, VEGF maintained its angiogenic activity as assessed by increased tubule formation of human umbilical vein endothelial cells (HUVEC) cultured on Matrigel (VEGF = 1937 ± 205 μm; scCO2-VEGF = 2085 ± 234 μm; control = 1237 ± 179 μm). VEGF release kinetics from scCO2-VEGF incorporated PLA monolith scaffolds showed a cumulative release of VEGF (2837 ± 761 ρg/ml) over a 21 day period in culture. In addition, VEGF encapsulated PLA scaffolds increased the blood vessel network in the CAM compared to controls; control, 24.8 ± 9.6; VEGF/PLA, 44.1 ± 12.1 (vessels/field). These studies demonstrate that the controlled release of growth factors encapsulated into three-dimensional PLA scaffolds can actively stimulate the rapid development of therapeutic neovascularisation to regenerate or engineer tissues.