•D-3 induces toxicity in iPSCs and ESCs within 1 hr of incubation•D-3 has little influence on various non-iPSCs, including hepatocytes and neurons•D-3 prevents residual iPSC-induced teratoma formation in an animal model•Alkaline phosphatase activity on the cell surface is required for D-3's toxicityThe incomplete differentiation of human induced pluripotent stem cells (iPSCs) poses a serious safety risk owing to their potential tumorigenicity, hindering their clinical application. Here, we explored the potential of phospho-D-peptides as novel iPSC-eliminating agents. Alkaline phosphatases overexpressed on iPSCs dephosphorylate phospho-D-peptides into hydrophobic peptides that aggregate and induce cell death. We isolated a peptide candidate, D-3, that selectively and rapidly induced toxicity in iPSCs within 1 hr but had little influence on various non-iPSCs, including primary hepatocytes and iPSC-derived cardiomyocytes. Two hours of D-3 treatment efficiently eliminated iPSCs from both single cultures and co-cultures spiked with increasing ratios of iPSCs. In addition, D-3 prevented residual iPSC-induced teratoma formation in a mouse tumorigenicity assay. These results suggest the enormous potential of D-3 as a low-cost and effective anti-iPSC agent for both laboratory use and for the safe clinical application of iPSC-derived cells in regenerative medicine.Download high-res image (185KB)Download full-size image

Molecular machines composed of RNA–protein (RNP) complexes may expand the fields of molecular robotics, nanomedicine, and synthetic biology. However, constructing and directly visualizing a functional RNP nanostructure to detect and control living cell function remains a challenge. Here we show that RNP nanostructures with modular functions can be designed and visualized at single-RNP resolution in real time. The RNP structural images collected in solution through high-speed atomic force microscopy showed that a single RNP interaction induces a conformational change in the RNA scaffold, which supports the nanostructure formation designed. The specific RNP interaction also improved RNA nanostructure stability in a serum-containing buffer. We developed and visualized functional RNPs (e.g., to detect human cancer cells or knockdown target genes) by attaching a protein or RNA module to the same RNA scaffold of an optimal size. The synthetic RNP architecture may provide alternative materials to detect and control functions in target mammalian cells.Keywords: high-speed atomic force microscopy; nanomedicine; RNA; RNA nanotechnology; RNAi; RNA−protein interaction; RNP nanostructures