Multisite Captured Copper Ions via Phosphorus Dendrons Functionalized Electrospun Short Nanofibrous Sponges for Bone Regeneration

Abstract Metal ions play an important role in promoting tissue regeneration. However, excessive metal ions can also cause certain damage to the human body. In this study, the electrospun short nanofibrous sponges (3D‐NS) functionalized with phosphorus dendrons (3D‐NS@PD) are innovatively constructed, which are capable of dynamically capturing free copper ions at multiple sites to realize the dynamic balance and physiological concentration of copper ions. First, phosphorus dendrons with the long hydrophobic alkyl chain are synthesized by substitution and condensation reactions with hexachlorocyclic triphosphazene as the core. Then, ten pyrrole groups are modified on the surface of phosphorus dendrons, some of which are grafted with copper ions by coordination method, and the remaining pyrrole groups are used to capture free copper ions at multiple sites. Furthermore, phosphorus dendrons modified with pyrrole groups are grafted onto 3D‐NS via π–π conjugation. The captured copper ions can enhance the mechanical properties of the 3D‐NS@PD, which shows stable 3D shape and reversible water absorption after repeated compression by external forces. In vitro and in vivo results show that 3D‐NS@PD effectively promotes bone regeneration by accelerating the formation of neovascularization at the defect sites and regulating the osteogenic differentiation of local bone marrow mesenchymal stem cells.