Localized Mechanical Stimulation and Characterization of Neuronal Cell Responses by Scanning Ion-Conductance...

In this study, scanning ion-conductance microscopy (SICM) is established as a multifunctional nanoscale platform for localized mechanical stimulation, high-resolution topographic imaging, and quantitative mapping of cellular Young's modulus. Using controlled force interactions between a nanopipette tip and the sample, we achieved spatially resolved mechanical activation of primary rat hippocampal neurons and astrocytes. Localized mechanical stimulation of specific subcellular regions induced elevations in intracellular Ca²⁺ levels, indicating the activation of mechanosensitive ion channels. Concurrent topographic imaging and Young's modulus mapping revealed that mechanical stimulation triggered distinct cytoskeletal remodeling responses. Specifically, stimulation of the neuronal cell body led to a significant increase in Young's modulus (stiffening), whereas dendritic stimulation produced no measurable change. In contrast, astrocytes exhibited bidirectional responses: somatic stimulation decreased Young's modulus (softening), while stimulation of astrocytic processes increased it (stiffening). Inhibition of actin polymerization with cytochalasin D completely abolished all stimulation-induced changes in Young's modulus in both cell types. Collectively, our findings demonstrate that SICM enables direct correlation of applied nanomechanical forces, intracellular calcium dynamics, and real-time alterations in cellular stiffness, thereby offering new insights into compartment-specific mechanotransduction pathways and adaptive cytoskeletal reorganization.