Preparation of siloxane-containing vaterite particles with red-blood-cell-like morphologies and incorporation of calcium-salt polylactide for bone regenerative medicine

Abstract

Siloxane-containing vaterite (SiV) particles with red-blood-cell-like morphologies were prepared by a CO2 gas carbonation process for application as osteogenic devices in bone tissue engineering. The particles release soluble silica species and calcium ions, which are expected to genetically stimulate osteoblasts to enhance bone reconstruction. The released particles possessed the mean diameter of 2 μΦ with the thickness of approximately 0.7 μm. The Brenauer-Emmett-Teller surface area was estimated to be 76m2·g-1. In addition, the shape of the nitrogen adsorption-desorption hysteresis of the particles indicated the presence of slit- or wedge-shaped mesoporous structures. The particles were primarily composed of vaterite with aminopropyl-functionalised siloxanes in the silicon mass percentage of approximately 2 wt %. Soluble silica species and a trace amount of calcium ion were released into the physiological pH buffer solution (pH 7.4) during the initial 1 h of soaking. To estimate its potential for loading functional molecules, polylactide (PLA) was used as the model molecule and the SiV particles were prepared in their presence. Fourier transform infrared spectrometry of the sample revealed that PLA formed a carboxylate salt with the calcium ions and was loaded into the mesoporous structures. Upon contact with the buffer solution, the calcium-salt PLA and siloxane were released simultaneously within the initial 1 h of soaking. © 2013 The Ceramic Society of Japan. All rights reserved.