Mineralized DNA Scaffold Boosts Bone Repair by Reprogramming Immune Cells

A new study developed a mineralized DNA hydrogel called “Cap-gel” that combines immune regulation with sustained bone regeneration. Using tetrahedral DNA nanostructures and calcium phosphate mineralization, researchers created a scaffold that promotes healing-friendly macrophage activity while supporting bone-forming stem cells. In animal models, the material accelerated bone repair, improved tissue mineralization, and prolonged structural stability. The findings may advance next-generation biomaterials for craniofacial reconstruction, traumatic injuries, and challenging bone healing disorders worldwide.

The scientists focused on two biological processes essential for bone repair: inflammation control and osteogenesis, the formation of new bone tissue. Cap-gel was designed to encourage macrophages to switch into the “M2” healing phenotype, which promotes tissue regeneration. At the same time, the mineralized structure of Cap-Gel acted as a long-term reservoir of calcium ions, which are crucial for bone formation and cellular signaling. The researchers found that the hydrogel gradually released calcium over several weeks, activating pathways linked to osteogenic differentiation. Bone marrow stem cells exposed to Cap-gel showed stronger expression of osteogenic proteins compared with control groups. The material also promoted the formation of mineralized nodules, demonstrating active bone-building activity.

To evaluate the material in living systems, the team implanted Cap-Gel into skull bone defects in rats. Imaging and tissue analyses showed that the hydrogel accelerated bone repair. Early after implantation, the material reduced inflammatory infiltration and increased the presence of pro-healing macrophages. Over time, defects treated with Cap-Gel developed denser collagen networks, more organized bone structures, and greater bone volume than untreated controls or non-mineralized hydrogels. After eight weeks, the regenerated bone displayed mature architecture and stronger mineralization.

The researchers believe the study could encourage collaborations across regenerative medicine, biomaterials science, nanotechnology, and immunology. Because the material combines programmable DNA nanostructures with bioactive mineral components, it may inspire future strategies for cartilage repair, dental reconstruction, chronic wound healing, and implant integration.