Injectable biomimetic hetero-structured short-fiber microspheres for constructing micro-ossification centers for bone...

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Tissue Engineering

Background:

• Ossification centers are crucial for bone development, offering a heterogeneous microenvironment ideal for bone regeneration.
• Mimicking the complex structure and function of ossification centers presents a significant challenge in regenerative medicine.

Purpose of the Study:

• To construct injectable biomimetic heterogeneous short-fiber microspheres (ZnCaP@NF-GF) that accurately simulate the structure and function of ossification centers.
• To investigate the potential of ZnCaP@NF-GF in promoting bone tissue regeneration.

Main Methods:

• Fabrication of inorganic/organic composite zinc-doped calcium phosphate-mineralized microspheres entangled with short fibers using charge coupling and electrospray microfluidic techniques.
• Dynamic self-assembly of platelet-derived growth factor-BB (PDGF-BB) with short-fiber microspheres via π-π conjugation and dopamine catechol groups.
• In vitro and in vivo evaluation of the microspheres' efficacy in bone defect repair.

Main Results:

• The developed ZnCaP@NF-GF exhibited a fibrous network for anchoring in bone defects and sustained release of PDGF-BB, calcium, and zinc ions.
• PDGF-BB effectively recruited endogenous stem cells via the CXCR axis.
• Sustained release of calcium and zinc ions induced stem cell osteogenic differentiation (MAPK/ERK pathway) and promoted new vascular network generation (ERBB/ERK signaling axis), respectively.
• ZnCaP@NF-GF acted as nucleation sites for biomineralized 'bone islands', demonstrating successful bone regeneration.

Conclusions:

• The injectable ZnCaP@NF-GF successfully mimics the heterogeneous structure and function of ossification centers.
• This biomimetic approach provides a promising strategy for enhancing bone tissue regeneration in defective bone areas.
• The study offers new insights into designing advanced biomaterials for orthopedic applications.