Telomere G-triplex lights up Thioflavin T for RNA detection: new wine in an old bottle

Few reports are found working on the features and functions of the human telomere G-triplex (ht-G3) though the telomere G-quadruplex has been intensely studied and widely implemented to develop various biosensors. We herein report that ht-G3 lights up Thioflavin T (ThT) and establish a sensitive biosensing platform for RNA detection by introducing a target recycling strategy. An optimal condition was selected out for ht-G3 to promote ThT to generate a strong fluorescence. Accordingly, an ht-G3-based molecular beacon was successfully designed against the corresponding RNA sequence of the SARS-CoV-2 N-gene. The sensitivity for the non-amplified RNA target achieves 0.01 nM, improved 100 times over the conventional ThT–based method. We believe this ht-G3/ThT–based label-free strategy could be widely applied for RNA detection. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00216-022-04180-7.