Carbon dioxide infusion of composite electrospun fibers for tissue engineering

Abstract

Supercritical fluids present an approach capable of enhancing the chemical activity of composite tissue engineering scaffolds. Previous attempts to embed test compounds into electrospun polycaprolactone (PCL) alone above 6.20MPa and temperatures above 25°C resulted in loss of biomimicry. In this study, PCL–gelatin blends were explored as a less sensitive yet more bioactive electrospun scaffold allowing the use of increased pressures and temperatures. The presence of the gelatin renders these electrospun fibers far less sensitive to supercritical CO2 exposure. PCL swelling and gelatin compression occur simultaneously and this volumetric compensation stabilizes the PCL within the blend without overall deformation. ATR observations suggest that these exposures increase the mobility of the amorphous content. In cases where XRD shows no crystalline content peaks prior to CO2 treatment, post-exposure crystalline regions are detected. PCL–gelatin scaffolds infused at either 8.27MPa or 10.34MPa subcritical conditions increase Rhodamine B loading concentrations 5-fold compared to scaffolds infused at only at 6.20MPa. PCL–gelatin scaffolds infused supercritically at either 8.27MPa or 10.34MPa showed increased loading of Rhodamine B compared to scaffolds infused at 6.20MPa but produce significantly lower released concentrations compared to 8.27MPa or 10.34MPa subcritically infused scaffolds. These are likely a result of Rhodamine B's solubility being significantly greater in liquid CO2 compared to gaseous or supercritical CO2.