Poly(acrylic acid)-grafted metal-organic framework carrying Mg ions for bone repair

In the field of biomedicine, metal-organic frameworks (MOFs) have been extensively studied. However, few studies have applied them to bone healing. In recent years, iron-based MOFs such as MIL-100(Fe) have been proven biocompatible and suitable for drug delivery applications. We used water-phase synthesis methods to prepare MIL-100(Fe) and NH₂ functionalized MIL-100(Fe). We then performed post-synthesis modification to incorporate Magnesium (Mg) ions into the cages of the MIL-100(Fe) (i.e., Mg@MIL-100(Fe)). The poly(acrylic acid) (PAA) modification on the surface of Mg@MIL-100(Fe) (i.e., Mg@MIL-100(Fe)-PAA) prevented the Mg ions from leaking, thus significantly increasing the Mg loading. The cytotoxicity test of the osteoblast-like cell line MG-63 showed that Mg@MIL-100(Fe)-PAA was biocompatible and could slightly improve cell proliferation. Furthermore, the ALP assay showed that Mg@MIL-100(Fe)-PAA could alter the time course of cell differentiation, which could eventually accelerate the bone healing process. These findings revealed the potential of utilizing metal-organic frameworks as bone repairing materials.