Porous CDHA microspheres laden brushite-based injectable bone substitutes for improved bone regeneration

Area of Science:

• Biomaterials Science
• Orthopedic Research
• Regenerative Medicine

Background:

• Injectable calcium phosphate cement (CPC) is a key material for bone regeneration.
• Enhancing CPC's degradation rate and bioactivity is crucial for improved bone healing.
• Porous calcium-deficient hydroxyapatite (CDHA) microspheres offer potential for scaffold development.

Purpose of the Study:

• To incorporate porous CDHA microspheres into injectable CPC.
• To evaluate the effect of CDHA microspheres on CPC's physical, chemical, and biological properties.
• To assess the efficacy of the novel CPC/CDHA composite as a bone substitute for regeneration.

Main Methods:

• Porous CDHA microspheres were integrated into CPC at varying concentrations (0-30 vol%).
• Setting time, compressive strength, in vitro degradation, and cytocompatibility were assessed.
• In vivo studies in rat femoral defects were conducted to evaluate bone formation.

Main Results:

• CPC setting time ranged from 12-17 min, suitable for surgical application.
• Optimal compressive strength was achieved with 20 vol% CDHA, with degradation and bioactivity enhanced.
• Histological and in vivo analyses showed significant new bone formation and cell infiltration in CPC/CDHA composites compared to CPC alone.

Conclusions:

• Injectable CPC modified with 20 vol% porous CDHA microspheres demonstrates suitable physical properties and enhanced bioactivity.
• The CPC/CDHA composite promotes cell migration and significantly increases bone formation in vivo.
• This novel injectable bone substitute holds promise for effective bone regeneration applications.