In vitro osteogenesis by intracellular uptake of strontium containing bioactive glass nanoparticles
In vitro osteogenesis by intracellular uptake of strontium containing bioactive glass nanoparticles
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DOI：
10.1016/j.actbio.2017.11.008
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发表时间：
2018-01-15
影响因子：
9.7
通讯作者：
Jones, Julian R.
中科院分区：
文献类型：
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作者：
Naruphontjiralcul, Parichart;Porter, Alexandra E.;Jones, Julian R.
通过改进的溶胶-凝胶Stober工艺，合成了具有两种成分的单分散锶含生物活性玻璃纳米颗粒（Sr-BGNPs），其中二氧化硅纳米颗粒（SiO2-NPs）在钙和锶掺入之前形成，直径为90 +/- 10 nm。以小鼠成骨前细胞系MC3T3-E1为实验材料，研究了纳米颗粒浓度为250 μ g/mL，含有87 mol% SiO2、7 mol% CaO、6 mol% SrO和83 mol% SiO2、3 mol% CaO、14 mol% SrO的体外成骨反应。在pH为7.4的最低必需介质（α - mem）和pH为4.5的人工溶酶体液（ALF）中进行的溶解研究表明，在这两种环境下，颗粒溶解，Sr2+离子从Sr-BGNPs中释放出来。颗粒组成及其离子溶解产物均能增强细胞碱性磷酸酶（ALP）活性和钙沉积。免疫组化（IHC）染色显示，培养3周后，MC3T3-E1细胞中有Col1a1、骨钙素（OSC）和骨桥蛋白（OSP）表达。在基础条件下，含有14 mol% SrO的Sr-BGNPs及其离子释放产物培养的细胞比对照条件下更明显地表达了晚期成骨分化标志物OSC和OSP。在基础条件下，Col1a1的表达仅略有增强，但在成骨补充剂中进一步增强。这些数据表明，Sr-BGNPs在没有成骨补充剂的情况下加速矿化。Sr-BGNPs通过内吞作用内化到MC3T3-E1细胞中，刺激成骨前细胞系的成骨分化。Sr-BGNPs可能有利于骨再生，这些颗粒的成骨作用可归因于它们的离子释放产物。我们首次报道了单分散的生物活性玻璃纳米颗粒（类似于90 nm）通过内吞作用被内化到成骨前细胞中，但其机制不明确。生物活性纳米颗粒及其溶解产物（不含颗粒）在不添加其他成骨补充剂的情况下刺激成骨前细胞成骨标志物的表达。在生物活性玻璃纳米颗粒组合物中加入锶和钙，增加了纳米颗粒的总阳离子含量（从而提高了溶解速度），即使名义上总阳离子添加量不变，也不会改变其大小或形态。增加纳米颗粒及其溶解产物中的锶含量可促进体外成骨。因此，这些颗粒作为一种可注射治疗骨再生的巨大潜力，特别是在骨质疏松症患者中，锶是已知的治疗剂。(C) 2017材料学报Elsevier Ltd.出版。版权所有。
Monodispersed strontium containing bioactive glass nanoparticles (Sr-BGNPs) with two compositions were synthesised, through a modified sol-gel Stober process, wherein silica nanoparticles (SiO2-NPs) were formed prior to incorporation of calcium and strontium, with diameters of 90 +/- 10 nm. The osteogenic response of a murine preosteoblast cell line, MC3T3-E1, was investigated in vitro for a nanoparticle concentration of 250 mu g/mL with compositions of 87 mol% SiO2, 7 mol% CaO, 6 mol% SrO and 83 mol% SiO2, 3 mol% CaO, 14 mol% SrO. Dissolution studies in minimum essential media (alpha-MEM) at pH 7.4 and artificial lysosomal fluid (ALF) at pH 4.5 showed that the particles dissolved and that Sr2+ ions were released from Sr-BGNPs in both environments. Both particle compositions and their ionic dissolution products enhanced the alkaline phosphatase (ALP) activity of the cells and calcium deposition. Immunohistochemistry (IHC) staining of Col1a1, osteocalcin (OSC) and osteopontin (OSP) showed that these proteins were expressed in the MC3T3-E1 cells following three weeks of culture. In the basal condition, the late osteogenic differentiation markers, OSC and OSP, were more overtly expressed by cells cultured with Sr-BGNPs with 14 mol% SrO and their ionic release products than in the control condition. Col1a1 expression was only slightly enhanced in the basal condition, but was enhanced further by the osteogenic supplements. These data demonstrate that Sr-BGNPs accelerate mineralisation without osteogenic supplements. Sr-BGNPs were internalised into MC3T3-E1 cells by endocytosis and stimulated osteogenic differentiation of the pre-osteoblast cell line. Sr-BGNPs are likely to be beneficial for bone regeneration and the observed osteogenic effects of these particles can be attributed to their ionic release products.Statement of SignificanceWe report, for the first time, that monodispersed bioactive glass nanoparticles (similar to 90 nm) are internalised into preosteoblast cells by endocytosis but by unspecific mechanisms. The bioactive nanoparticles and their dissolution products (without the particles present) stimulated the expression of osteogenic markers from preosteoblast cells without the addition of other osteogenic supplements.Incorporating Sr into the bioactive glass nanoparticle composition, in addition to Ca, increased the total cation content (and therefore dissolution rate) of the nanoparticles, even though nominal total cation addition was constant, without changing size or morphology.Increasing Sr content in the nanoparticles and in their dissolution products enhanced osteogenesis in vitro. The particles therefore have great potential as an injectable therapeutic for bone regeneration, particularly in patients with osteoporosis, for which Sr is known to be therapeutic agent. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.