Purification of Milli-Q water by sub-boiling distilled and employment of qualified FBS could increase the AKP staining positive level and total clone formation rate of mouse ES cells.

• Milli-Q水经亚沸处理能显著提高ES细胞保持未分化状态的能力，优质胎牛血清能提高ES的AKP阳性度和克隆形成率。