After isolating tissues from human embryos, they are rapidly frozen in isopentane cooled with liquid nitrogen and then sectioned. The tissue sections are digested at 37°C in 0.25% trypsin solution (Gibco) to prepare a single-cell suspension. The cells are then washed with DPBS and filtered through a 40μm filter (Bel-Art) Library construction was carried out the GEXSCOPETM Single-Cell RNA Library Kit (Singleron Biotechnologies), adhering to the Singleron GEXSCOPETM protocol.