The development of a nanocrystalline apatite reinforced crosslinked hyaluronic acid–tyramine composite as an injectable bone cement

✍ Scribed by Y. Shona Pek; Motoichi Kurisawa; Shujun Gao; Joo E. Chung; Jackie Y. Ying

• Book ID: 104003754
• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 887 KB
• Volume: 30
• Category: Article
• ISSN: 0142-9612
• DOI: 10.1016/j.biomaterials.2008.10.053

✦ Synopsis

We have developed an injectable bone cement composed of nanocrystalline apatite and crosslinked hyaluronic acid-tyramine conjugates (HA-Tyr). This bone cement was formed via the oxidative coupling of tyramine moieties catalyzed by hydrogen peroxide (H 2 O 2 ) and horseradish peroxidise (HRP). The bone cement set within 60 s after H 2 O 2 and HRP were added to the apatite/HA-Tyr pastes. The mechanical strength of the apatite/HA-Tyr cement was tuned by varying the apatite loading and H 2 O 2 concentration. This rapid enzyme-mediated setting of our bone cement results in minimal heat release (DH ¼ À11.39 J/g) as compared to conventional bone cements. The crystalline phase and crystallite size (20 nm) of the apatitic phase in our bone cement matched that of trabecular bone. The storage modulus (G 0 ), yield stress (s y ), and compressive stiffness (E c ) of our bone cement prepared with different apatite loadings and H 2 O 2 concentrations were measured, and optimized at G 0 ¼ 40 MPa, s y ¼ 0.308 MPa and E c ¼ 2.270 MPa when the cement was formed with 0.4 g/ml of apatite, 0.61 units/ml of HRP and 6.8 mM of H 2 O 2 . Our biocompatible bone cement also successfully healed small bone and joint defects in mice within 8 weeks.