骨水泥的杨氏模量测试
Biosilica, a biocompatible, natural inorganic polymer that is formed by an enzymatic, silicatein-mediated reaction
in siliceous sponges to build up their inorganic skeleton, has been shown to be morphogenetically active and to
induce mineralization of human osteoblast-like cells (SaOS-2) in vitro. In the present study, we prepared beads
(microspheres) by encapsulation of β-tricalcium phosphate [β-TCP], either alone (control) or supplemented
with silica or silicatein, into the biodegradable copolymer poly(D,L-lactide-co-glycolide) [PLGA]. Under the conditions
used, ≈5% β-TCP, ≈9% silica, and 0.32 μg/mg of silicatein were entrapped into the PLGA microspheres
(diameter≈800 μm). Determination of the biocompatibility of the β-TCP microspheres, supplemented with silica
or silicatein, revealed no toxicity in the MTT based cell viability assay using SaOS-2 cells. The adherence of
SaOS-2 cells to the surface of silica-containing microspheres was higher than for microspheres, containing only
β-TCP. The formation of new bone induced by the microspheres is also evident from
measurements of the stiffness/reduced Young's modulus of the regenerated bone tissue. The reduced Young's
modulus of the regenerating bone tissue around the implants was markedly higher for the silica-containing microspheres
(1.1 MPa), and even more for the 1:1 mixture of the silica- and silicatein-containing microspheres
(1.4 MPa), compared to the β-TCP microsphere controls (0.4 MPa). We propose that based on their morphogenetic
activity on bone-forming cells in vitro and the results of the animal experiments presented here, silica/
biosilica-based scaffolds are promising materials for bone repair/regeneration.