High-strength, in situ-setting calcium phosphate composite with protein release

✍ Scribed by Michael D. Weir; Hockin H.K. Xu

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 656 KB
• Volume: 85A
• Category: Article
• ISSN: 1549-3296
• DOI: 10.1002/jbm.a.31347

✦ Synopsis

Abstract

The aim of this study was to develop a mechanically‐strong calcium phosphate cement (CPC) with protein release. Chitosan was used to strengthen CPC and control protein release. Mass fraction of protein release = mass of released protein/mass of total protein incorporated into the specimen. Flexural strength (mean ± sd; n = 6) of CPC containing 100 ng/mL of protein increased from 8.0 ± 1.4 MPa with 0% chitosan, to 19.8 ± 1.4 MPa with 15% chitosan (p < 0.05). The latter exceeded the reported strengths of sintered porous hydroxyapatite implants and cancellous bone. When the chitosan mass fraction was increased from 0% to 10% and 15%, protein release varied from 0.60 ± 0.03 to 0.41 ± 0.04, and to 0.23 ± 0.07, respectively (p < 0.05). When powder:liquid ratio increased from 2:1 to 3:1 and 4:1, protein release changed from 0.89 ± 0.10 to 0.41 ± 0.04, and to 0.23 ± 0.07, respectively p < 0.05. Therefore, chitosan content and powder:liquid ratio successfully controlled the protein release. The protein release mass fraction, M, was related to CPC porosity P by: M = 16.9 P^4.5^. In summary, a mechanically‐strong CPC with controlled protein release was formulated. Protein release was proportional to CPC porosity. The in situ‐hardening, nano‐apatite composite may have potential for bone tissue engineering, especially when both mechanical strength and controlled release of therapeutic/bioactive agents are needed. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008