Instrument: HiSeq X Ten
Strategy: RNA-Seq
Source: TRANSCRIPTOMIC
Selection: cDNA
Layout: PAIRED
Construction protocol: Cardiac cells from monolayer differentiation culture at day 15 and day 30 were dissociated with TrypLE and washed once with HBSS-/- (Ca2+/Mg2+ free). The cardiac organoids were sequencially incubated with 0.25% Trypsin/EDTA and a collagenase HBSS+/+ mixture before filtered through a 40 μm filter. The cells from each sample were stained with with a unique MULTI-seq barcode separately and pooled before library preparation. The pooled cells were captured in 10X Chromium (10X Genomics, 120223) by following the single cell 3' reagent kits v3 user guide. Briefly, cells were loaded into each chip well to be partitioned into gel beads in emulsion (GEMs) in the Chromium controller. We targeted for 25,000 cells in each chip well and profiled one well for the first batch experiment and two chip wells for the second experiment. The cells were then lysed and barcoded reverse transcribed in the GEMs. After breaking the GEMs and further cleanup and amplification, the cDNA was enzymatically fragmented and 3′ end fragments were selected for library preparation. After further processing including end repair, A-tailing, adaptor ligation, and PCR amplification, a string of sequences including sample index, UMI sequences, barcode sequences, and sequencing primer P5 and P7 were added to cDNA on both ends. The libraries were sequenced on Illumina HiSeq X platform.