One week after fertilization, human embryos implant into the uterus. This event requires the embryo to form a blastocyst consisting of a sphere encircling a cavity lodging the embryo proper. Stem cells can form a blastocyst model that we called a blastoid¹. Here we show that naive human pluripotent stem cells cultured in PXGL medium² and triply inhibited for the Hippo, TGF-β and ERK pathways efficiently (with more than 70% efficiency) form blastoids generating blastocyst-stage analogues of the three founding lineages (more than 97% trophectoderm, epiblast and primitive endoderm) according to the sequence and timing of blastocyst development. Blastoids spontaneously form the first axis, and we observe that the epiblast induces the local maturation of the polar trophectoderm, thereby endowing blastoids with the capacity to directionally attach to hormonally stimulated endometrial cells, as during implantation. Thus, we propose that such a human blastoid is a faithful, scalable and ethical model for investigating human implantation and development^3,4.

受精后一周，人类胚胎植入子宫。此事件需要胚胎形成一个囊胚，该囊胚由一个球体组成，该球体环绕着容纳胚胎的空腔。干细胞可以形成我们称为胚泡^{1 的}胚泡模型。^{在这里，我们展示了在 PXGL 培养基2}中培养的幼稚人类多能干细胞并且三重抑制 Hippo、TGF-β 和 ERK 通路，有效地（效率超过 70%）形成胚细胞，根据序列产生三个创始谱系（超过 97% 的滋养外胚层、外胚层和原始内胚层）的囊胚期类似物和胚泡发育的时间。Blastoids 自发形成第一个轴，我们观察到外胚层诱导极地滋养外胚层的局部成熟，从而赋予 blastoids 定向附着在激素刺激的子宫内膜细胞上的能力，就像在植入过程中一样。因此，我们建议这样的人类胚细胞是用于研究人类植入和发育的忠实、可扩展且合乎道德的模型^3,4。