Fast setting calcium phosphate cement-chitosan composite: mechanical properties and dissolution rates

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Tissue Engineering

Background:

• Calcium phosphate cement (CPC) is osteoconductive but can have slow setting times and lower mechanical strength.
• Chitosan incorporation into CPC aims to improve mechanical properties and washout resistance.
• Understanding the impact of chitosan on CPC's setting, strength, and bioresorbability is crucial for clinical applications.

Purpose of the Study:

• To optimize the setting time and mechanical properties of CPC-chitosan composites by varying chitosan content.
• To evaluate the in vitro bioresorbability of CPC-chitosan composites in simulated acidic environments.
• To determine the suitability of CPC-chitosan composites for moderate stress-bearing applications.

Main Methods:

• Synthesized CPC-chitosan composites with chitosan mass fractions of 0%, 10%, 15%, 20%, 25%, and 30%.
• Measured setting time and flexural strength of the composite materials.
• Assessed in vitro dissolution in solutions with pH 3.5-5, simulating osteoclast activity, over 7-28 days.

Main Results:

• The CPC-chitosan composite with 20% chitosan exhibited a significantly reduced setting time (13 ± 1 min) compared to control CPC (87 ± 7 min).
• Flexural strength was significantly enhanced to 14 ± 2 MPa for the 20% chitosan composite, versus 4 ± 1 MPa for control CPC.
• Dissolution rates in acidic conditions were comparable for both CPC-chitosan and control CPC, indicating preserved bioresorbability.

Conclusions:

• A CPC-chitosan composite with optimized 20% chitosan content demonstrates fast-setting properties and significantly improved mechanical strength.
• The addition of chitosan does not compromise the bioresorbability of CPC in acidic environments.
• This strong and resorbable CPC-chitosan composite shows potential for craniofacial and orthopedic repairs requiring moderate load-bearing capacity.