Construction of bFGF/heparin and FeO nanoparticles functionalized scaffolds aiming at vascular repair and magnetic resonance imaging monitoring.

This work develops a bioactive basic fibroblast growth factor (bFGF)/heparin and FeO nanoparticles (NPs) trifunctionalized degradable construct with the potential of using as a vascular tissue engineering scaffold with the aim of improving vascular repair and regeneration therapy. The covalent modification of heparin onto the poly(lactic acid) (PLA)-gelatin (Gel)-FeO (PGF) scaffold improves the hydrophilicity of the scaffold. Furthermore, the electrostatic adsorption of bFGF on heparin allows for a more consistent and prolonged release of bFGF in situ, hence increasing the stability and effectiveness of bFGF around the surrounding vascular tissues. The sustained release of bFGF promotes the M2 macrophage polarization, and adhesion and migration of macrophages and endothelial cells (ECs), providing a stable and favorable microenvironment for vascular regeneration. Furthermore, the covalently modified heparin minimizes platelet adhesion on the scaffold surface, potentially contributing to the long-term patency of the vascular tissue engineering scaffold. Including FeO NPs in the scaffold delays degradation and provides an in vivo magnetic resonance imaging (MRI) effect to monitor the scaffold's location and in vivo degradation. Furthermore, the mild photothermal effect of FeO NPs plays a facilitating role in bFGF release, immune modulation, and ECs manipulation, therefore contributary to the vascular tissue reconstruction.