Core-shell microspheres delivering FGF-2 and BMP-2 in different release patterns for bone regeneration.

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Tissue Engineering

Background:

• Bone regeneration is complex, involving multiple growth factors (GFs) like fibroblast growth factor-2 (FGF-2) and bone morphogenetic protein-2 (BMP-2).
• Optimizing the temporal delivery of dual GFs for bone regeneration remains a significant challenge for clinical translation.
• Existing delivery systems struggle to control the precise release kinetics of multiple GFs.

Purpose of the Study:

• To investigate the long-term effects of different temporal release patterns of FGF-2 and BMP-2 on bone regeneration.
• To develop and evaluate a novel PLLA core-PLGA shell double-walled microsphere system for controlled dual GF delivery.
• To compare the efficacy of sequential versus simultaneous GF release for critical-sized bone defect repair.

Main Methods:

• Fabrication of PLLA core-PLGA shell double-walled microspheres to achieve distinct FGF-2 and BMP-2 release profiles.
• In vivo evaluation of different dual GF release patterns in a rat critical-sized bone graft model.
• In vitro assessment of FGF-2 and BMP-2 effects on osteoclastogenesis in bovine bone sections.

Main Results:

• Sequential delivery of FGF-2 followed by BMP-2 significantly improved bone bridging and remodeling of critical-sized bone grafts compared to other patterns.
• Simultaneous and continuous release of FGF-2 and BMP-2 led to graft resorption and non-union at 4 weeks.
• In vitro studies showed that combined FGF-2 and BMP-2 treatment enhanced osteoclastogenesis more than single GF treatments.

Conclusions:

• Temporal control over FGF-2 and BMP-2 delivery is critical for successful bone regeneration.
• Core-shell microspheres offer a promising platform for achieving precise temporal organization of dual GFs.
• This strategy holds potential for developing more effective therapeutic devices for bone defects.