A bone implant is a medical device used to replace or repair damaged or missing bone tissue. Bone implants can be made from various materials, such as metals, ceramics, or polymers, and can have different shapes and sizes depending on the location and extent of the bone defect. The implant is typically surgically inserted into the affected area and secured to the remaining healthy bone tissue using screws, plates, or other fixation devices. The implant provides mechanical support and stability to the bone while promoting new bone formation and integration. The success of a bone implant depends on various factors, such as the choice of material, implant design, surgical technique, and patient factors, such as age and overall health.

A “soft-hard” bone implant (BM-g-DPCL) consisting of a bioactive matrix chemically integrated on a polydopamine (PDA)-coated porous gradient scaffold by polyphenol groups is constructed. The PDA-coated “hard” scaffolds promoted Ca2+ chelation and mineral deposition; the “soft” bioactive matrix is beneficial to the migration, proliferation, and osteogenic differentiation of stem cells in vitro, accelerated endogenous stem cell recruitment and initiated rapid angiogenesis in vivo. The results of the rabbit cranial defect model (Φ = 10 mm) confirmed that BM-g-DPCL promoted the integration between bone tissue and implant and induced the deposition of bone matrix. Proteomics confirmed that cytokine adhesion, biomineralization, rapid vascularization, and extracellular matrix formation are major factors that accelerate bone defect healing. This strategy of highly chemically bonded soft-hard components guided the construction of the bioactive regenerative scaffold ¹⁾.