Preparation of large-scale digitization samples for automated electron microscopy of tissue and cell ultrastructure

Manual selection of targets in experimental or diagnostic samples by transmission electron microscopy (TEM), based on single overview and detail micrographs, has been time-consuming and susceptible to bias. Substantial information and throughput gain may now be achieved by automated acquisition of virtually all structures in a given EM section. Resulting datasets allow convenient pan-and-zoom examination of tissue ultrastructure with preserved microanatomical orientation. The technique is, however, critically sensitive to artifacts in sample preparation. We therefore established a methodology to prepare large-scale digitization samples (LDS) designed to acquire entire sections free of obscuring flaws. For evaluation, we highlight the supreme performance of scanning EM in transmission mode compared to other EM technology. The use of LDS will substantially facilitate access to EM data for a broad range of applications.