Semi-automated optimized method to isolate CRISPR/Cas9 edited human pluripotent stem cell clones
Background: CRISPR/Cas9 editing systems are currently used to generate mutations in a particular gene to mimic a genetic disorder in vitro. Such “disease in a dish” models based on human pluripotent stem cells (hPSCs) offer the opportunity to have access to virtually all cell types of the human body. However, the generation of mutated hPSCs remains fastidious. Current CRISPR/Cas9 editing approaches lead to a mixed cell population containing simultaneously non-edited and a variety of edited cells. These edited hPSCs need therefore to be isolated through manual dilution cloning that is time-consuming, labor intensive and tedious.  Methods: Following CRISPR/Cas9 edition, we obtained a mixed cell population with various edited cells. We then used a semi-automated robotic platform to isolate single cell derived clones.  Results: We optimized CRISPR/Cas9 editing to knock out a representative gene and developed a semi-automated method for the clonal isolation of edited hPSCs. This method is faster and more reliable than current manual approaches.  Conclusions:  This novel method of hPSC clonal isolation will greatly improve and upscale the generation of edited hPSCs required for down-stream applications including disease modeling and drug screening.