Department of Surgical, Medical, Molecular Pathology and Emergency Medicine, University of Pisa, via Paradisa 2, I-56124 Pisa, Italy. Center for the Clinical Use of Stem Cells-Regional Network of Regenerative Medicine 'CUCCS-RRMR', University of Pisa, via Roma 55, I-56126 Pisa, Italy.
Nanotechnology. 2013 Nov 22;24(46):465102. doi: 10.1088/0957-4484/24/46/465102. Epub 2013 Oct 22.
In this paper we investigated a novel and non-invasive approach for an endogenous osteoblast stimulation mediated by boron nitride nanotubes (BNNTs). Specifically, following the cellular uptake of the piezoelectric nanotubes, cultures of primary human osteoblasts (hOBs) were irradiated with low frequency ultrasound (US), as a simple method to apply a mechanical input to the cells loaded with BNNTs. This in vitro study was aimed at investigating the main interactions between hOBs and BNNTs and to study the effects of the 'BNNTs + US' stimulatory method on the osteoblastic function and maturation.A non-cytotoxic BNNT concentration to be used in vitro with hOB cultures was established. Moreover, investigation with transmission electron microscopy/electron energy loss spectroscopy (TEM/EELS) confirmed that BNNTs were internalized in membranal vesicles. The panel of investigated osteoblastic markers disclosed that BNNTs were capable of fostering the expression of late-stage bone proteins in vitro, without using any mineralizing culture supplements. In our samples, the maximal osteopontin expression, with the highest osteocalcin and Ca(2+) production, in the presence of mineral matrix with nodular morphology, was observed in the samples treated with BNNTs + US. In this group was also shown a significantly enhanced synthesis of TGF-β1, a molecule sensitive to electric stimulation in bone. Finally, gene deregulations of the analyzed osteoblastic genes leading to depletive cellular effects were not detected. Due to their piezoelectricity, BNNT-based therapies might disclose advancements in the treatment of bone diseases.
在本文中，我们研究了一种新型的非侵入性方法，通过氮化硼纳米管（BNNTs）介导内源性成骨细胞刺激。具体来说，在压电纳米管被细胞摄取后，原代人成骨细胞（hOB）的培养物用低频超声（US）照射，作为向负载 BNNTs 的细胞施加机械输入的简单方法。这项体外研究旨在研究 hOB 和 BNNTs 之间的主要相互作用，并研究“BNNTs+US”刺激方法对成骨细胞功能和成熟的影响。建立了一种用于体外 hOB 培养的非细胞毒性 BNNT 浓度。此外，透射电子显微镜/电子能量损失光谱（TEM/EELS）的研究证实 BNNTs 被内化在膜泡中。所研究的成骨细胞标志物表明，BNNTs 能够在体外促进晚期骨蛋白的表达，而无需使用任何矿化培养补充剂。在我们的样本中，在存在具有结节形态的矿化基质的情况下，观察到 BNNTs+US 处理的样品中骨桥蛋白表达最高，骨钙素和 Ca（2+）产量最高。在该组中，还显示出 TGF-β1 的合成明显增强，TGF-β1 是一种对骨骼电刺激敏感的分子。最后，未检测到分析的成骨基因的基因失调导致细胞耗竭效应。由于其压电性，基于 BNNT 的治疗方法可能会在骨病治疗方面取得进展。
