Effect of Soy Protein Addition on the Setting and Compression Strength of Brushite-HA Cement

This study involved the preparation of calcium phosphate cement which consists of a mixture of brushite (DCPD) and hydroxyapatite (HA) powder synthesized in a laboratory. Buffer solution was used as liquid phase and mixed with the mixture of DCPD and HA powder to produce in-situ bone cement with liquid to powder ratio (L/P) between 0.26 and 0.36 mL g^-1. Sodium alginate and soy protein was added into the calcium phosphate cement and its affect on the cement was studied. Results showed that the calcium phosphate cement could be formed with maximum injectability (100%) and setting time of 26 min at L/P ratio of 0.32 mL g^-1 with addition of 1wt% sodium alginate and 1wt% protein. Addition of soy protein increased compressive strength of the bone cement from 2.90 MPa (without protein) to 3.98 MPa at 1.5wt% protein. The calcium phosphate-soy protein cement also exhibited bioactivity properties. The growth of apatite has been observed after 3 days soaking in SBF solution and growth with time.