Tailoring cryo-electron microscopy grids by photo-micropatterning for in-cell structural studies

Micropatterning of cryo-EM grids enables controlled adhesion of mammalian cells for cryo-ET-based structural studies. This approach leads to reproducible cellular morphology and improves focused ion beam thinning of cells for in-cell structural analyses. Spatially controlled cell adhesion on electron microscopy supports remains a bottleneck in specimen preparation for cellular cryo-electron tomography. Here, we describe contactless and mask-free photo-micropatterning of electron microscopy grids for site-specific deposition of extracellular matrix-related proteins. We attained refined cell positioning for micromachining by cryo-focused ion beam milling. Complex micropatterns generated predictable intracellular organization, allowing direct correlation between cell architecture and in-cell three-dimensional structural characterization of the underlying molecular machinery.