A current bottleneck in the advance of neurophysics is the lack of reliable methods to quantitatively measure the interactions between neural cells and their microenvironment. Here, we present an experimental technique to probe the fundamental characteristics of neuron adhesion through repeated peeling of well-developed neurite branches on a substrate with an atomic force microscopy cantilever. At the same time, a total internal reflection fluorescence microscope is also used to monitor the activities of neural cell adhesion molecules (NCAMs) during detaching. It was found that NCAMs aggregate into clusters at the neurite-substrate interface, resulting in strong local attachment with an adhesion energy of ∼0.1 mJ/m2 and sudden force jumps in the recorded force-displacement curve. Furthermore, by introducing a healing period between two forced peelings, we showed that stable neurite-substrate attachment can be re-established in 2-5 min. These findings are rationalized by a stochastic model, accounting for the breakage and rebinding of NCAM-based molecular bonds along the interface, and provide new insights into the mechanics of neuron adhesion as well as many related biological processes including axon outgrowth and nerve regeneration.

中文翻译：

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通过强制剥离和时间依赖性愈合揭示神经元粘附的基本特征

当前神经物理学进步的一个瓶颈是缺乏可靠的方法来定量测量神经细胞与其微环境之间的相互作用。在这里，我们提出了一种实验技术，通过用原子力显微镜悬臂反复剥离基板上发育良好的神经突分支来探测神经元粘附的基本特征。同时，还使用全内反射荧光显微镜监测分离过程中神经细胞粘附分子（NCAMs）的活性。发现 NCAM 在轴突-基底界面处聚集成簇，导致强烈的局部附着，粘附能约为 0.1 mJ/m2，并在记录的力 - 位移曲线中突然发生力跳跃。此外，通过在两次强制脱皮之间引入愈合期，我们表明可以在 2-5 分钟内重新建立稳定的轴突-基底附着。这些发现通过随机模型合理化，解释了基于 NCAM 的分子键沿界面的断裂和重新结合，并为神经元粘附机制以及许多相关的生物过程（包括轴突生长和神经再生）提供了新的见解。