In-Situ Hardening Hydroxyapatite-Based Scaffold for Bone Repair

Published

July 7, 2005

Author(s)

Yu Zhang, Hockin D. Xu, Shozo Takagi, Laurence C. Chow

Abstract

Musculoskeletal conditions are becoming a major health concern because of an aging population and sports- and traffic-related injuries. While sintered hydroxyapatite implants require machining, calcium phosphate cement (CPC) bone repair material is moldable, self-hardens in situ, and has excellent osteoconductivity. In the present work, new approaches for strong and macroporous scaffolds of CPC were tested. Relationships were determined between scaffold porosity and strength, elastic modulus and fracture toughness. A biocompatible and biodegradable polymer (chitosan) and a water-soluble porogen (mannitol) were incorporated into CPC: Chitosan to make the material stronger, fast-setting and anti-washout; and mannitol to create macropores. Flexural strength, elastic modulus, and fracture toughness were measured as functions of mannitol mass fraction in CPC from 0 % to 75 %.After mannitol dissolution, macropores were formed in CPC in the shapes of the original entrapped mannitol crystals, with diameters of 50 mm to 200 mm. The resulting porosity in CPC ranged from 34.4 % to 83.3 % volume fraction. At 70.2 % porosity, the hydroxyapatite scaffold possessed flexural strength (mean sd; n = 6) of (2.5 0.2) MPa and elastic modulus of (0.71 0.10) GPa. These values were within the range for sintered porous hydroxyapatite and cancellous bone. Predictive equations were established by regression power-law fitting to the measured data (R2 > 0.98) that described the relationships between scaffold porosity and strength, elastic modulus and fracture toughness.

Citation

Journal of Materials Science

Volume

17

Issue

5

Pub Type

Journals

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Keywords

bone tissue engineering, calcium phosphate cement, hydroxyapatite, in-situ hardening, macropores, scaffold, strength

Citation

Zhang, Y. , Xu, H. , Takagi, S. and Chow, L. (2005), In-Situ Hardening Hydroxyapatite-Based Scaffold for Bone Repair, Journal of Materials Science, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852374 (Accessed January 15, 2025)