A functional mineralized collagen hydrogel to promote angiogenic and osteogenic for osseointegration of 3D-printed titanium alloy microporous scaffolds

Bone defects, resulting from trauma, inflammation, tumors, and various other factors, affect both health and quality of life. Although autologous bone transplantation is the gold-standard treatment for bone defects, it has disadvantages such as donor site limitations, prolonged surgical durations, and potential complications, necessitating the development of alternative bone tissue engineering materials. In this study, we used 3D printing technology to fabricate porous titanium implants characterized by superior biocompatibility and mechanical properties. Sodium alginate (SA) and strontium ions (Sr2+) were integrated into mineralized collagen matrices (MCs) to develop strontium-functionalized alginate-mineralized collagen hydrogels (SAMs) with high mechanical strength and sustained metal ion release ability. SAMs were seamlessly incorporated into the porous structures of 3D-printed titanium scaffolds, establishing a novel organic-inorganic bioactive interface. This composite system exhibited high biocompatibility in vitro and increased the expression of genes important for osteogenic differentiation and angiogenesis. In a rabbit model of femoral defect, the titanium implants effectively promoted bone and vascular regeneration on their surface, highlighting their potential in facilitating bone-implant integration.

The Influence of Surface Bioactivated Modification on Titanium Percutaneous Implants Anchored in Bone

In order to achieve biological sealing and resist mechanical damage of load-bearing percutaneous devices, Ti with excellent mechanical properties was anodic-oxidized to be endowed with bioactivity, with plasma-sprayed hydroxyapatite coated Ti as control. Similar to previous works, hydroxyapatite coating could bond tightly with living tissues, resulting in implant stability for whole implantation periods. Meanwhile, when anodic-oxidized bioactivated Ti was implanted percutaneously in vivo, it could induce a layer of calcium phosphate at the interface of tissues/implant. This layer of Ca-P not only induced the fibrous tissue or collagen ingrowth in its structure, but also improved the osteointegration between the bone and the implant. There was no significant biological response difference for the anodic-oxidized Ti and HA coated Ti at different implantation period with histological statistical analysis (p>0.05). Accordingly, suitable bioactivated modified surface of Ti by anodic-oxidized method could not only obtain the same results as the HA coating, but also might avoid some drawbacks of plasma-sprayed HA coatings to achieve biological sealing for a long period in vivo.