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