Development of injectable cuttlebone derived nanohydroxyapatite hydrogel for osteoblast cell encapsulation

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Nanotechnology

Background:

• Bone regeneration requires effective delivery systems for osteogenic factors.
• Injectable hydrogels offer minimally invasive solutions for bone defect treatment.
• Cuttlebone-derived nanohydroxyapatite (CB-nHA) and quercetin (QT) show potential for enhancing bone healing.

Purpose of the Study:

• To create bioactive, injectable, thermosensitive hydrogels for bone regeneration.
• To investigate the influence of CB-nHA and QT-loaded microcapsules on hydrogel properties.
• To optimize hydrogel formulation for enhanced osteoconductivity and injectability.

Main Methods:

• Fabrication of chitosan/collagen hydrogels with varying CB-nHA concentrations and chitosan:collagen ratios.
• Incorporation of calcium carbonate microcapsules loaded with quercetin (CaCO3-QT).
• Evaluation of hydrogel microstructure, mechanical properties, rheology, injectability, cytotoxicity, and osteoconductivity using human fetal osteoblasts (hFOB).

Main Results:

• Higher CB-nHA and chitosan concentrations increased mechanical strength but reduced pore size and degradation.
• The optimal hydrogel (5% CB-nHA, 1% CaCO3-QT, 7:1 chitosan:collagen) was injectable with a pore size of 116 ± 47 μm.
• Encapsulated hFOBs showed high viability, robust intercellular connections, and significantly increased ALP activity compared to controls.

Conclusions:

• CB-nHA and CaCO3-QT significantly enhance the osteoconductive properties of injectable hydrogels.
• The optimized thermosensitive hydrogel serves as a bioactive carrier for osteoblasts and QT, promoting bone regeneration.
• This formulation represents a promising strategy for treating bone defects through enhanced osteogenesis.