Precisely Localized Bone Regeneration Mediated by Marine-Derived Microdroplets with Superior BMP-2 Binding Affinity

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Drug Delivery Systems

Background:

• Supraphysiological doses of bone morphogenetic protein-2 (BMP-2) achieve bone regeneration but cause adverse effects due to rapid clearance.
• Uncontrolled BMP-2 release leads to complications like heterotopic ossification and soft tissue inflammation.
• Developing sustained-release BMP-2 delivery systems is crucial for safe and effective bone regeneration.

Purpose of the Study:

• To fabricate a novel complex coacervate using fucoidan and poly-l-lysine (PLL) for localized and sustained BMP-2 delivery.
• To enhance BMP-2 bioactivity and therapeutic action while preventing denaturation and proteolysis.
• To evaluate the efficacy of BMP-2 loaded coacervate coated collagen sponges in promoting bone regeneration.

Main Methods:

• Fabrication of a complex coacervate from fucoidan (marine glycosaminoglycan) and poly-l-lysine (PLL).
• Microencapsulation of BMP-2 within the coacervate, leveraging electrostatic interactions for efficient loading and protection.
• Coating BMP-2-loaded coacervate onto collagen sponges for localized delivery.
• In vitro evaluation using human-derived stem cells and in vivo assessment in a calvarial bone defect model.

Main Results:

• The fucoidan-PLL coacervate demonstrated superior BMP-2 binding and efficient microencapsulation.
• Encapsulated BMP-2 exhibited enhanced bioactivity and protection against antagonists and proteolysis.
• The coacervate system facilitated prolonged BMP-2 release.
• In vitro and in vivo studies confirmed the bioactivity and localized bone regenerating potential of the BMP-2 coacervate-coated sponges.

Conclusions:

• The fucoidan-PLL complex coacervate serves as an effective vehicle for localized and sustained delivery of BMP-2.
• This approach mitigates the risks associated with burst release, improving the safety profile for bone regeneration therapies.
• The developed system shows significant promise for enhancing bone regeneration in clinical applications.