CRISPR/Cas13a assisted amplification of magnetic relaxation switching sensing for accurate detection of miRNA-21 in human serum

Development of rapid and accurate detection of miRNAs in complex samples is of great significance for potential early diagnosis of disease. Herein, we report a magnetic relaxation switching (MRS)-based strategy for direct detection of miRNAs in complex samples via the assistance of signal amplification system of CRISPR/Cas13a which has the ability to specifically recognize target RNA. In the designed strategy, 30 nm-magnetic nanoparticles (MB30) and 1000 nm-magnetic particles (MM1000) linked by single-strand RNA1 complexes (MB30-RNA(1)-MM1000) were employed as signal probe. After the target miRNAs (taking miR-21 as model) recognition by CRISPR/Cas13a system, the resulted trans-cleavage degrades the MB30-RNA(1)-MM1000, releasing MB30 which caused transverse relaxation time (T-2) signal change. The combination of CRISPR/Cas13a assisted signal amplification and the MRS assay achieved direct detection of miR-21 in the serum sample without extracting within 60min, with a detection limit of 0.22 pM. Moreover, the detection accuracy is confirmed by performing the detection of miR-21 using qRT-PCR. The CRISPR/Cas13a system assisted MRS assay successfully achieved accurate, simple, and rapid detection of miRNAs in complex samples, showing great potential for detection miRNAs in potential clinical applications.

Automated summary

Developing rapid and accurate methods for detecting miRNA in complex samples is crucial for early disease diagnosis. Researchers have developed a magnetic relaxation switching (MRS)-based strategy for direct detection of miRNA in complex samples using the CRISPR/Cas13a signal amplification system. This method achieves accurate and rapid detection of miRNA without the need for sample extraction, and has a high detection sensitivity.