Preparation of porous apatite granules from calcium phosphate cement

摘要

A versatile method for preparing spherical, micro- and macroporous (micro: 2-10 and macro: 150-550 μm pores), carbonated apatitic calcium phosphate (Ap-CaP) granules (2-4 mm in size) was developed by using NaCl crystals as the porogen. The entire granule production was performed between 21 and 37 ℃. A CaP cement powder, comprising a-Ca_3(PO_4)_2 (61 wt.%), CaH-PO_4 (26%), CaCO_3 (10%) and precipitated hydroxyapatite, Ca_(10)(PO_4)_6(OH)_2 (3%), was dry mixed with NaCl crystals varying in size from 420 μm to 1 mm. Cement powder (35 wt.%) and NaCl (65 wt.%) mixture was kneaded with an ethanol-Na_2HPO_4 initiator solution, and the formed dough was immediately agitated on an automatic sieve shaker for a few minutes to produce the spherical granules. Embedded NaCl crystals were then leached out of the granules by soaking them in deionized water. CaP granules were micro- and macroporous with a total porosity of 50% or more. Granules were composed of carbonated, poorly crystallized, apatitic CaP phase. These were the first spherical and porous CaP granules ever produced from a self-setting calcium phosphate cement. The granules reached their final handling strength at the ambient temperature through the cement setting reaction, without having a need for sintering.