Investigating Cell-Substrate Interactions Using Fib-Sem in Neuroelectronics Application

In tissue engineering, understanding the interaction between cells and substrates is crucial for the development of neuroelectronic devices^1,2. Focused Ion Beam – Scanning Electron Microscopy (FIB-SEM) has emerged as a powerful technique to investigate these interactions, particularly as we transition from 2D to 3D environments. This study highlights the use of FIB-SEM in examining the electromechanical coupling between primary cortical neurons and biomimetic microelectrodes. Utilizing advanced techniques like two-photon lithography and "salami slicing" for precise milling and imaging, the study preserves neuronal integrity through ultra-thin plasticization^3–5. This method enables high-resolution 3D reconstructions, revealing how neurons conform to microelectrode topographies. The findings demonstrate that neuron membranes deform inward around nanoscale protrusions more readily than outward around invaginations, influencing the cleft width between cell membranes and substrates. This deeper understanding of cell-material interactions has significant implications for the design and functionality of medical implants and biosensors, advancing the field of neuroelectronics.<br/><br/>(1) Mariano, A.; Lubrano, C.; Bruno, U.; Ausilio, C.; Dinger, N. B.; Santoro, F. Advances in Cell-Conductive Polymer Biointerfaces and Role of the Plasma Membrane. <i>Chem. Rev.</i> <b>2021</b>. https://doi.org/10.1021/acs.chemrev.1c00363.<br/>(2) Mariano, A.; Bovio, C. L.; Criscuolo, V.; Santoro, F. Bioinspired Micro- and Nano-Structured Neural Interfaces. <i>Nanotechnology</i> <b>2022</b>. https://doi.org/10.1088/1361-6528/ac8881.<br/>(3) A. Belu; J . Schnitker; S. Bertazzo; E. Neumann; D. Mayer; A. Offenhausser; Santoro, F. Ultra-Thin Resin Embedding Method for Scanning Electron Microscopy of Individual Cells on High and Low Aspect Ratio 3D Nanostructures. <i>Journal of Microscopy</i>. December 9, 2015. http://onlinelibrary.wiley.com/doi/10.1111/jmi.12378/full.<br/>(4) Dipalo, M.; McGuire, A. F.; Lou, H.-Y.; Caprettini, V.; Melle, G.; Bruno, G.; Lubrano, C.; Matino, L.; Li, X.; De Angelis, F.; Cui, B.; Santoro, F. Cells Adhering to 3D Vertical Nanostructures: Cell Membrane Reshaping without Stable Internalization. <i>Nano Lett.</i> <b>2018</b>, <i>18</i> (9), 6100–6105. https://doi.org/10.1021/acs.nanolett.8b03163.<br/>(5) Santoro, F.; Zhao, W.; Joubert, L.-M.; Duan, L.; Schnitker, J. Revealing the Cell–Material Interface with Nanometer Resolution by Focused Ion Beam/Scanning Electron Microscopy. <i>ACS Nano</i> <b>2017</b>, 9.