How to split a G-quadruplex for DNA detection: new insight into the formation of DNA split G-quadruplex† †Electronic supplementary information (ESI) available: DNA sequence, Fig. S1–S11, Tables S1–S4, extended experimental details and discussions. See DOI: 10.1039/c5sc01287b Click here for additional data file.

Here, we get a new insight into the formation of a split G-quadruplex from the viewpoints of the split mode and guanine base number. An unusual result is that the split mode 4 : 8 performed best in six split modes, including the frequently used mode 1 : 3 and 2 : 2 in the split G-quadruplex enhanced fluorescence assay. Circular dichroism spectra verified the conclusion. The application of the split G-quadruplex based assay in DNA detection was performed on the point mutations of the JAK2 V617F and HBB genes. A multi-target analysis method based on a pool of G-segments split from T30695 (GGGTGGGTGGGTGGGT) by the magic “law of 4 : 8” was established.