Switch-conversional ratiometric fluorescence biosensor for miRNA detection

Publication date: Available online 17 February 2020Source: Biosensors and BioelectronicsAuthor(s): Xian Chen, Ke Xu, Jing Li, Ming Yang, Xing Li, Qin Chen, Chunhua Lu, Huanghao YangAbstractMicroRNAs play a crucial role in regulating gene expression and cellular function. Reliable detection of miRNA is highly demanded in clinical diagnosis and therapy. Herein, we designed a structure-convertible DNA switch and constructed a novel switch-conversional ratiometric fluorescence biosensor (SCRF biosensor) for highly sensitive miRNA detection by the use of amplicon fragments to convert the structure of the switch. The DNA switch was a sophisticated designed single-strand DNA with a stem-loop structure and modified with two fluorophores (Cy3 and Cy5) and one quencher at specific sites of the switch. Amplicon fragments (c*) were produced by an exponential amplification reaction. When the c* hybridized to the loop of a DNA switch, the structure of the switch would convert, and fluorescence resonance energy transfer occurred between Cy5 and Cy3. Then two fluorescence signals with different trends would be observed. As a result, by the ratio of the two signals, we can quantitatively and quickly detect the target miRNA with the concentration range from 100 fM to 100 nM and the excellent detection limit down to 70.9 fM, providing this new SCRF biosensor broad application prospects.

Source: Biosensors and Bioelectronics - February 18, 2020 Category: Biotechnology Source Type: research