Development of a novel semi-quantitative analysis system for ultramicroscale samples by fluorescent capillary...

Microchemistry provides methods to analyze small quantities of chemical substances, including proteins, nucleic acids, and carbohydrates in various fields such as biomedical research, tissue engineering, molecular biology, and regeneration medicine. We therefore developed a fluorescent capillary isoelectric focusing (fluorescent cIEF) system for protein detection at an ultramicroscale volume, which aimed to isolate and identify, from a heterogeneous mixture of transduced cells, induced pluripotent stem cells (iPSCs) that could be fully reprogrammed. In addition, we demonstrated that the SOX2 protein, which is indispensable for the acquisition of pluripotency, could be detected by this new fluorescent cIEF system to identify iPSCs in the early phase of complete reprogramming. This method took less than 1 h for completion, including the time required for the antibody-antigen (Ab-Ag) reaction, and required as few as approximately three cells. Thus, this system could help improve iPSC generation as well as cut costs and reduce workloads.