Following microporation of 5 µM MBs that have no endogenous RNA targets into HeLa, HEK293, Jurkat, or primary BJ cells, the extent of MB opening was quantified over the course of 10 h . The MBs tested include 2Me (●), 2Me/PSSTEM (○), 2Me/PS10-LOOP (▴), 2Me/PSALT (△), 2Me/PSLOOP (■), and 2Me/PSFULL (□). Data are presented as mean ± S.E. from at least 30 cells. B. Representative images of MBs in HeLa cells, acquired at 10 h post microporation. The inset shows an expanded segment of the image. Arrows point to bright spots indicative of nonspecific binding in the nucleus (Scale bar, 10 µm). PS, phosphorothioate; MB, molecular beacon; 2Me, 2′-O-methyl. The graphs and images are reproduced with permission from Elsevier .