Fig. 1: Development and characterization of the TDF sensor.

A CircSCMH1 derived from the exon 6, 7, and 8 of the SCMH1 gene. B Predicted circSCMH1 structure calculated by RNAfold software. C Schematic illustration for sensing mechanism of TDF sensor. D AFM characterization demonstrating the successful formation of TDF. Scale bar, 100 nm. Experiments were repeated independently three times with similar results. E The average size of the TDF sensor derived from AFM image. F Fluorescence intensity of TDF sensor upon the addition of RNA extraction from circSCMH1 plasmid-transfected HEK293T and vector-transfected HEK293T cells. Data are presented as mean ± SEM, n = 9 different measurements/group. ^***P < 0.001 versus Con group using unpaired two-tailed Student’s t test. G Fluorescence intensity of TDF probe upon addition of different concentrations of circSCMH1 from plasmid-transfected HEK293T cells. Data are presented as mean ± SEM, n = 3 different measurements/group. H Fluorescence changes in response to the indicated compounds. Data are presented as mean ± SEM, n = 3 different measurements/group. I Fluorescence kinetic of TDF sensor upon addition of circSCMH1 (1 pM) isolated from transfected cells (i), short synthetic BSJ fragment RNA (1 pM) (ii), and short synthetic BSJ fragment RNA (300 nM) (iii). BSJ back-splice junction, arb. units arbitrary units; Source data are provided as a Source Data file.