Mesoporous calcium–silicon xerogels with mesopore size and pore volume influence hMSC behaviors by load and sustained release of rhBMP-2

Abstract

Mesoporous calcium–silicon xerogels with a pore size of 15 nm (MCS-15) and pore volume of 1.43 cm³/g were synthesized by using 1,3,5-mesitylene (TMB) as the pore-expanding agent. The MCS-15 exhibited good degradability with the weight loss of 50 wt% after soaking in Tris-HCl solution for 56 days, which was higher than the 30 wt% loss shown by mesoporous calcium–silicon xerogels with a pore size of 4 nm (MCS-4). The pore size and pore volume of MCS-15 had significant influences on load and release of recombinant human bone morphogenetic protein-2 (rhBMP-2). The MCS-15 had a higher capacity to encapsulate a large amount of rhBMP-2; it could adsorb 45 mg/g of rhBMP-2 in phosphate-buffered saline after 24 hours, which was more than twice that with MCS-4 (20 mg/g). Moreover, the MCS-15 system exhibited sustained release of rhBMP-2 as compared with MCS-4 system (showing a burst release). The MCS-15/rhBMP-2 system could promote the proliferation and differentiation of human mesenchymal stem cells, showing good cytocompatibility and bioactivity. The results indicated that MCS-15, with larger mesopore size and higher pore volume, might be a promising carrier for loading and sustained release of rhBMP-2, which could be used as bone repair material with built-in osteoinduction function in bone reconstruction.

Keywords:

• mesoporous calcium–silicon xerogels
• pore size
• pore volume
• load-release
• rhBMP-2

Acknowledgments

This study was supported by grants from the National Natural Science Foundation of China (Numbers 81271705, 31271031), the international cooperation project of Ministry of Science and Technology of China (Number 2013DFB50280), the Major Program of Natural Science Foundation of Shanghai, People’s Republic of China (Number 11JC1416302), Nano Special Program of Science and Technology Development of Shanghai (Number 12nm0500400), and Key Medical Program of Science and Technology Development of Shanghai (Numbers 12441903600, 12441902802).

Disclosure

The authors report no conflicts of interest in this work.