Life Science Department, Center for Neuroscience B.R.A.I.N., University of Trieste, via Giorgieri 1, I-34127 Trieste, Italy.
ACS Nano. 2012 Mar 27;6(3):2041-55. doi: 10.1021/nn203519r. Epub 2012 Feb 27.
New developments in nanotechnology are increasingly designed to modulate relevant interactions between nanomaterials and neurons, with the aim of exploiting the physical properties of synthetic materials to tune desired and specific biological processes. Carbon nanotubes have been applied in several areas of nerve tissue engineering to study cell behavior or to instruct the growth and organization of neural networks. Recent reports show that nanotubes can sustain and promote electrical activity in networks of cultured neurons. However, such results are usually limited to carbon nanotube/neuron hybrids formed on a monolayer of dissociated brain cells. In the present work, we used organotypic spinal slices to model multilayer tissue complexity, and we interfaced such spinal segments to carbon nanotube scaffolds for weeks. By immunofluorescence, scanning and transmission electronic microscopy, and atomic force microscopy, we investigated nerve fiber growth when neuronal processes exit the spinal explant and develop in direct contact to the substrate. By single-cell electrophysiology, we investigated the synaptic activity of visually identified ventral interneurons, within the ventral area of the explant, thus synaptically connected, but located remotely, to the substrate/network interface. Here we show that spinal cord explants interfaced for weeks to purified carbon nanotube scaffolds expand more neuronal fibers, characterized by different mechanical properties and displaying higher growth cones activity. On the other hand, exploring spontaneous and evoked synaptic activity unmasks an increase in synaptic efficacy in neurons located at as far as 5 cell layers from the cell-substrate interactions.
纳米技术的新发展越来越多地旨在调节纳米材料和神经元之间的相关相互作用，目的是利用合成材料的物理特性来调整所需的特定生物过程。碳纳米管已应用于神经组织工程的多个领域，以研究细胞行为或指导神经网络的生长和组织。最近的报告表明，纳米管可以维持和促进培养神经元网络中的电活动。然而，这些结果通常仅限于在分离的脑细胞单层上形成的碳纳米管/神经元杂化体。在本工作中，我们使用器官型脊髓切片来模拟多层组织复杂性，并将这些脊髓段与碳纳米管支架连接数周。通过免疫荧光、扫描和透射电子显微镜以及原子力显微镜，我们研究了当神经元过程离开脊髓外植体并与基底物直接接触时神经纤维的生长。通过单细胞电生理学，我们研究了位于外植体腹侧区域内的可视鉴定腹侧中间神经元的突触活性，因此它们通过突触连接，但位于远离基底物/网络界面的位置。在这里，我们表明，与纯化的碳纳米管支架连接数周的脊髓外植体扩展了更多的神经元纤维，其特征在于具有不同机械性能并显示出更高的生长锥活性。另一方面，探索自发和诱发的突触活性揭示了距离细胞-基底物相互作用最远可达 5 个细胞层的神经元中突触效能的增加。
