Single-cell sequencing technologies are revolutionizing biology, but they are limited by the need to dissociate live samples. Researchers from Oxford Brookes University have developed ACME (ACetic-MEthanol), a dissociation approach for single-cell transcriptomics that simultaneously fixes cells. ACME-dissociated cells have high RNA integrity, can be cryopreserved multiple times, and are sortable and permeable. As a proof of principle, the researchers provide single-cell transcriptomic data of different species, using both droplet-based and combinatorial barcoding single-cell methods. ACME uses affordable reagents, can be done in most laboratories and even in the field, and thus will accelerate our knowledge of cell types across the tree of life.
ACME cell dissociation and fixation
a Whole dissociation process for the planarian Schmidtea mediterranea. From left to right: live worms used as input in water, ACME dissociation reaction after 10–60 min, cell suspension after final pipetting, pellet after first centrifugation, and pellet after second centrifugation in PBS 1% BSA. b–e Flow cytometry profiles of S. mediterranea ACME-dissociated cells stained with DRAQ5 (nucleus) and Concanavalin-A (cytoplasm): ungated (b), after gating singlets by FSC (c), and DRAQ5 (d). Area vs height, and resulting clean G1 (red) and G2 (cyan) populations. Singlets are selected based on their well-correlated area vs height signal, while aggregates display high area vs height ratios. f Relative proportion of singlets in a typical S. mediterranea ACME cell dissociation, corresponding to 22.8% of the total events, and histogram of their DNA content (linear scale), showing the relative proportions of G1 and G2 cells. g Bright field (BF) and confocal fluorescence (Fluo) microscopy images of S. mediterranea ACME-dissociated cells stained with Concanavalin-A and DRAQ5, showing single cells, aggregates, and debris (top) and details of different cell types with well-preserved morphology (bottom). Scale bars are 50 μm (top) and 5 μm (bottom)