Metal-organic framework-based nanomaterials for bone tissue engineering and wound healing

Over the past decade, tremendous growth has been witnessed in the synthesis of scaffolds fabricated by natural or synthetic, composite, or hybrid biomaterials to enhance wound healing, repair of bone fractures, and pathological loss of bones. However, the current limitations of using these scaffolds in tissue engineering are impaired cellular proliferation, poor differentiation, low mechanical stability, and bioactivity. Recent advances in the fabrication of nanoscale metal-organic framework (nano-MOF) scaffolds have provided golden opportunities to enhance the properties of scaffolds in bone and wound tissue engineering. In the past few years, studies have shown that incorporating nano-MOFs into scaffolds can be highly favorable in the regeneration of imperfect tissues owing to their unique properties such as high internal surface areas, high porosity, good mechanical stability, biocompatibility, and tunability. Moreover, the nanoscale structural and topological properties of nano-MOFs enhance the physicochemical properties of scaffolds, enrich them with drug-loading and ion-releasing capacity, and regulate stem cell attachment, proliferation, and differentiation after transplantation. This review initially introduces the various nano-MOFs incorporated into scaffolds for tissue engineering. Recent applications of nanoMOFs for bone and wound healing are comprehensively discussed. The unique properties of nano-MOFs for improving osteoconductivity, osteoinductivity, and wound healing, such as high antibacterial activity, high drug loading capacity (i.e., bioactive molecules and growth factors), and controlled drug release, are discussed. Finally, challenges, clinical barriers, and considerations for implementing these nanomaterials in different scaffolds, tissue-like structures, implants, fillers, and dressers in the orthopedic and wound clinics are comprised.