Sustained release and activation of the growth factor basic fibroblast growth factor from loaded scaffolds in heart valve tissue engineering

OBJECTIVES: Loading of biological matrices offers an opportunity to induce specific cell behaviour. We previously reported the use of growth factors to promote cell invasion and proliferation in tissue valve engineering. We investigated biological matrices preloaded with heparin as an ionically attractive template for the binding, activation and sustained release of basic fibroblast growth factor (bFGF). METHODS: Heparin loading concentrations were evaluated and different incubation times were tested. Heparin and heparin-bound bFGF uptake and release were evaluated by (123)I radio-labelling. Biological activity of bFGF was evaluated in vitro. RESULTS: Maximum heparin uptake was observed for 2000 microg/ml at 2 h and stabilized thereafter. bFGF-loaded matrices showed an initial burst release of 15% within 4 h and thereafter sustained release reaching 21% at 24 h. Released bFGF was bioactive. CONCLUSIONS: This model would be useful in tissue engineering using porcine aortic matrices and could be applied using other growth factors or combinations.