A universal lateral flow assay for microRNA visual detection in urine samples

MicroRNAs (miRNAs) have been emerged as novel and significant biomarkers in liquid biopsy that can be found in different body fluids. Several techniques have been developed and applied for miRNAs analysis, including nucleic acid-based amplification methods, next generation sequencing, DNA microarrays and new genomeediting methods. These methods, however, are time-consuming and require expensive instruments and specially trained personnel. Biosensors, on the other hand, are alternative and valuable analytical/diagnostic tools due to their simplicity, cost-effectiveness, rapid analysis and ease of use. Several biosensors, especially nanotechnology-based ones, have been developed for miRNA analysis that are based either on target amplification or signal amplification and target re-cycling for sensitive detection. At this point of view, we have introduced a new and universal lateral flow assay in combination with reverse transcription - polymerase chain reaction (RT-PCR) and gold nanoparticles as reporters for the detection of miR-21 and miR-let-7a in human urine. It is the first time that such a biosensor has been applied to the detection of microRNAs in urine. As low as 10(2)-10(3) copies of miR-21 and 10(2-)-10(4) copies of miR-let-7a added in urine were detectable by the proposed lateral flow assay with great specificity and repeatability (%CVs <4.5%).

Automated summary

MicroRNAs (miRNAs) have emerged as novel and significant biomarkers in liquid biopsy for their presence in different body fluids. While various techniques have been developed and applied for miRNA analysis, they can be time-consuming and require expensive instruments and trained personnel. Biosensors, especially nanotechnology-based ones, have been developed as alternative and valuable tools for miRNA analysis due to their simplicity, cost-effectiveness, rapid analysis, and ease of use.