Dual aptamer-functionalized in situ injectable fibrin hydrogel for promotion of angiogenesis via co-delivery of growth factors

Introduction: Biomaterials have been extensively used to deliver growth factors for promotion of therapeutic angiogenesis. Among those materials, hydrogels are the most promising delivery vehicle because of their biophysical and biochemical similarity to native tissues [1]. One major drawback of using hydrogel as growth factor delivery system is the quick release of the loaded growth factors due to the high permeability of hydrogels [2]. The burst release of angiogenic growth factors from hydrogel can lead to short therapeutic duration and even toxic effects. In addition, multiple growth factors are needed during the process of angiogenesis, such as vascular endothelial growth factor (VEGF) for initiating the angiogenesis process and platelet derived growth factor (PDGF) for stabilizing newly formed blood vessels [3]. To be able to control the release of multiple angiogenic growth factors from hydrogel system will have the potential to further improve therapeutic angiogenesis.