Capturing Magnesium Ions via Microfluidic Hydrogel Microspheres for Promoting Cancellous Bone Regeneration

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedics

Background:

• Metal ions are vital for metabolism and tissue repair.
• Magnesium ions (Mg2+) combined with bone materials promote vascular repair and osteoblast adhesion.
• Osteoporotic bone defects require advanced treatment strategies.

Purpose of the Study:

• To construct a bisphosphonate-functionalized injectable hydrogel microsphere (GelMA-BP-Mg) for promoting cancellous bone reconstruction.
• To leverage coordination chemistry for Mg2+ capture and sustained release.
• To investigate the efficacy of Mg2+-capturing microspheres in treating osteoporotic bone defects.

Main Methods:

• Grafting bisphosphonate (BP) onto GelMA microspheres to create Mg2+ capture sites.
• Utilizing coordination reactions for Mg2+ binding and sustained release.
• Evaluating Mg2+ capture percentage (0.6%) and release duration (18 days).
• Assessing *in vitro* and *in vivo* effects on osteogenesis, angiogenesis, and osteoclast activity.

Main Results:

• GelMA-BP-Mg microspheres demonstrated significant Mg2+ capture and sustained release capabilities.
• The composite microspheres effectively activated osteoblasts and endothelial cells while inhibiting osteoclasts.
• *In vivo* and *in vitro* studies confirmed enhanced osteogenesis and angiogenesis.
• Cancellous bone regeneration was effectively promoted in osteoporotic bone defects.

Conclusions:

• Magnet-inspired Mg2+-capturing composite microspheres are beneficial for osteoporotic bone defect treatment.
• The system effectively promotes bone regeneration by modulating cellular activities.
• This approach offers novel strategies for metal ion-based therapies in bone defect repair.