Biodegradable, phosphate-containing, dual-gelling macromers for cellular delivery in bone tissue engineering

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Developing injectable biomaterials for bone regeneration is crucial.
• Mesenchymal stem cells (MSCs) hold promise for tissue repair.
• Current materials often lack optimal biointegration and degradation profiles.

Purpose of the Study:

• To develop injectable, biodegradable hydrogels for MSC delivery.
• To assess hydrogel performance in vitro and in vivo for craniofacial bone defects.
• To investigate the impact of macromer chemistry on biointegration and bone formation.

Main Methods:

• Synthesized N-isopropyl acrylamide-based macromers with pendant phosphate groups.
• Encapsulated MSCs within dual-gelling hydrogels at physiologic temperature.
• Evaluated MSC viability, hydrogel mineralization in vitro, and degradation in vivo.
• Implanted cell-laden and acellular hydrogels into rat cranial defects.

Main Results:

• MSCs survived encapsulation and remained viable in hydrogels for 28 days in vitro.
• Hydrogels mineralized in osteogenic medium and degraded in vivo.
• Both cell-laden and acellular hydrogels facilitated bone growth into defects.
• Improved bone bridging and direct bone-to-hydrogel contact were observed with cell incorporation and higher phosphate content.

Conclusions:

• Injectable, dual-gelling macromers effectively deliver MSCs for bone tissue engineering.
• These hydrogels support MSC viability, degrade appropriately, and promote bone regeneration.
• The developed macromers represent a promising material for craniofacial bone defect repair.