A light-up fluorescence platform based DNA: RNA hybrid G-quadruplet for detecting single nucleotide variant of ctDNA and miRNA-21

The nucleic acid assay is an area of great concern in the diagnosis and treatment of breast cancer. Here, we developed a DNA: RNA hybrid G-quadruplet (HQ) detection platform based on strand displacement amplification (SDA) and Baby Spinach RNA aptamer for single nucleotide variant (SNV) of circulating tumor DNA (ctDNA) and miRNA-21. This was the first in vitro construction of HQ for the biosensor. It found that HQ had much stronger ability to switch on fluorescence of DFHBI-1T than Baby Spinach RNA alone. Taking advantage of the platform and the FspI enzyme with high specificity, the biosensor achieved ultra-sensitive detection of SNV of the ctDNA (PIK3CA H1047R gene) and miRNA-21. The light-up biosensor had high anti-interference ability in complex actual samples. Hence, the label-free biosensor provided a sensitive and accurate method for early diagnosis of breast cancer. Moreover, it opened a new application model for RNA aptamers.

Automated summary

In this study, a DNA: RNA hybrid G-quadruplet (HQ) detection platform was developed using strand displacement amplification (SDA) and Baby Spinach RNA aptamer for the detection of single nucleotide variant (SNV) of circulating tumor DNA (ctDNA) and miRNA-21. The HQ-based biosensor showed stronger fluorescence activation of DFHBI-1T compared to Baby Spinach RNA alone. Through the use of the platform and the highly specific FspI enzyme, the biosensor achieved ultra-sensitive detection of SNV of ctDNA (PIK3CA H1047R gene) and miRNA-21, with high anti-interference ability in complex actual samples. This label-free biosensor provides a sensitive and accurate method for early diagnosis of breast cancer and opens up a new application model for RNA aptamers.