Structure and biocompatibility of an injectable bone regeneration composite

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Tissue Engineering

Background:

• Injectable materials are a key focus in biomaterials due to minimally invasive techniques.
• Developing effective injectable bone regeneration composites (IBRCs) is crucial for bone defect repair.

Purpose of the Study:

• To develop and characterize an injectable bone regeneration composite (IBRC) using calcium alginate hydrogel and nano-hydroxyapatite/collagen particles.
• To evaluate the homogeneity, pore properties, cytotoxicity, histocompatibility, and bone healing efficacy of the IBRC.

Main Methods:

• IBRC homogeneity assessed via dry/wet weight ratio.
• Pore sizes characterized using thermoporometry (wet) and mercury porosimetry (dried).
• In vitro cell culture with rat bone mesenchymal stem cells and in vivo studies in rat cranial defects.

Main Results:

• Structural homogeneity controlled by trisodium phosphate to calcium sulfate molar ratios, not alginate concentration.
• Dried IBRC pore size and porosity decreased with increasing alginate concentration.
• Wet homogeneous IBRC pore size increased with alginate concentration; swelling degree increased, but swelling ratio did not.
• IBRC demonstrated no cytotoxicity, good histocompatibility with mild inflammation, and promoted bone healing in cranial defects.

Conclusions:

• The developed IBRC is a promising injectable biomaterial for bone regeneration.
• Control over IBRC's structural and pore properties is achievable through specific formulation parameters.
• IBRC exhibits excellent biocompatibility and efficacy in promoting bone defect repair.