The Effect of Nano-Silica Gel on Biological Activity of Osteoblasts and Expression of Insulin-Like and Growth Factor-2

Abstract

This study assessed the effect nano-silica gel material on bioactivity of osteoblasts and expression of IGF-2. Methods: Silica gel nanoparticles (Nanjing Kike Company) were divided according to their concentrations as follows; 0 μg/mL a control group with cells without nanoparticle treatment, 25 μg/mL as group 1, 50 μg/mL as group 2, and 100 μg/mL as group 3. The transmission electron microscope was used to measure morphology, while particle size analyzer was used to measure particle size, and potential analyzer measured Zeta potential, and MTT measured proliferation.Moreover, ALP kit was used to measure ALP activity, and Alizarin red staining measured formation of wild flower nodules, while RT-PCR was used to measure expression of IGF-2. Results: The shape of silica gel nanoparticles was spherical, with uniform particle size distribution, and particle size was between 50–800 nm. The average particle size was 383 nm, and Zeta potential was −12.3. The growth rate of control group and group 1 was relatively close (t = 0.95, P = 0.37), and growth rate of groups 2 and 3 was higher than control (group t2 = 5.63, P < 0.05, group t3 = 10.38, P < 0.05). The value-added rate for group 3 was higher than group 2 (t = 4.41, P < 0.05). Group 1 had higher activity than control group (t = 10.29, P < 0.05) and lower activity than group 3 (t = 9.85, P < 0.05) which had higher activity than group 2 (t = 4.16, P < 0.05). Groups 1, 2, and 3 induced the growth of osteoblasts, promoted calcium salt deposition, and produced red mineralized nodules where the cells converged. The formation of mineralized nodules obviously depended on concentration of silica nanoparticles. Group 1 had higher IGF-2 expression than control (t = 19.99, P < 0.05) and lower level than group 2 (t = 16.69, P < 0.05). Silica gel nanoparticles promoted MC3T3-E1 cell proliferation and differentiation. The mechanism of action may be that, silica gel nanoparticles accelerate the growth of ALP activity and osteoblast extracellular matrix mineralization by promoting the level of IGF-2. The production of chemical nodules accelerates the proliferation and differentiation of osteoblasts.