In correlative light and electron microscopy (CLEM) workflows, identifying the same sub-cellular features in tissue by both light (LM) and electron microscopy (EM) remains a challenge. Furthermore, use of cryo-fixation for EM is desirable to capture rapid biological phenomena. Here, we describe a workflow that incorporates cryo-confocal laser scanning microscopy into the CLEM process, mapping cells in brain slices to re-image them with serial section scanning electron microscopy (ssSEM) array tomography. The addition of Airyscan detection increased the signal-to-noise ratio (SNR), allowing individual spines in thick frozen tissue to be visualized at a sufficient spatial resolution, providing a new tool for a CLEM approach to capture biological dynamics.
