Injectable PLGA based colloidal gels for zero-order dexamethasone release in cranial defects.

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Nanotechnology

Background:

• Bone defect repair often requires invasive surgery.
• Developing injectable bone fillers with controlled drug release is crucial for accelerated healing.
• Poly (D,L-lactic-co-glycolic acid) (PLGA) nanoparticles offer potential for novel bone filler applications.

Purpose of the Study:

• To create an injectable, cohesive colloidal gel bone filler using oppositely-charged PLGA nanoparticles.
• To investigate the material properties and drug release kinetics of the PLGA colloidal gel.
• To evaluate the in vivo efficacy of the PLGA colloidal gel in promoting bone formation.

Main Methods:

• Fabrication of a colloidal gel from oppositely-charged PLGA nanoparticles via electrostatic self-assembly.
• Characterization of the gel's rheological properties, including shear-thinning and recovery behavior.
• Encapsulation of dexamethasone within PLGA nanoparticles and assessment of drug release kinetics.
• In vivo implantation of the PLGA colloidal gel into rat cranial bone defects for efficacy evaluation.

Main Results:

• The PLGA colloidal gel exhibited stable 3-D network formation and shear-thinning behavior with reversible cohesion.
• Dexamethasone-loaded gels demonstrated near zero-order drug release over two months.
• The injectable, pseudoplastic nature facilitated surgical placement.
• In vivo studies showed the PLGA colloidal gels stimulated osteoconductive bone formation.

Conclusions:

• Oppositely-charged PLGA nanoparticles can form injectable, cohesive colloidal gels for bone defect repair.
• The developed material demonstrates favorable rheological properties and controlled drug delivery capabilities.
• PLGA colloidal gels effectively promote osteoconduction and bone regeneration in vivo.