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Published on: March 29, 2018
Oxidized alginate hydrogels for bone morphogenetic protein-2 delivery in long bone defects
Lauren B Priddy1, Ovijit Chaudhuri2, Hazel Y Stevens3
1Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, 315 Ferst Drive NW, Atlanta, GA 30332, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Drive NW, Atlanta, GA 30332, USA.
Oxidized alginate hydrogels enhanced bone regeneration by accelerating bone morphogenetic protein-2 (BMP-2) release and promoting faster degradation. This led to improved bone mineral density and more mature bone formation in a rat femoral defect model.
Area of Science:
- Biomaterials Science
- Regenerative Medicine
- Orthopedic Surgery
Background:
- Autograft limitations for bone defects necessitate alternative tissue engineering strategies.
- Alginate hydrogels offer biocompatibility and injectability for bone regeneration.
- Irradiated alginate hydrogels deliver bone morphogenetic protein-2 (BMP-2) but exhibit slow degradation.
Purpose of the Study:
- To evaluate the impact of alginate oxidation on BMP-2 release kinetics.
- To assess the in vivo bone regeneration capacity of oxidized-irradiated alginate hydrogels.
- To determine if faster degradation enhances bone quality and integration.
Main Methods:
- Oxidation and irradiation of alginate hydrogels.
- In vitro assessment of BMP-2 release and bioactivity.
- In vivo implantation in a rat femoral defect model.
- Radiography, micro-computed tomography, biomechanical testing, and histology for analysis.
Main Results:
- Oxidation accelerated in vitro BMP-2 release from alginate hydrogels.
- BMP-2 remained bioactive in both hydrogel types at 26 days.
- Both hydrogel types promoted robust bone regeneration over 12 weeks.
- Oxidized alginate showed enhanced degradation and greater bone mineral density at 8 weeks.
- Histology indicated more mature bone in the oxidized alginate group at 12 weeks.
Conclusions:
- Alginate oxidation accelerates BMP-2 release and enhances hydrogel degradation.
- Oxidized alginate hydrogels promote superior bone regeneration and maturation compared to non-oxidized counterparts.
- This modified hydrogel strategy shows promise for treating large bone defects and non-unions.
