Rapid and ultrasensitive miRNA detection by combining endonuclease reactions in a rolling circle amplification (RCA)-based hairpin DNA fluorescent assay.

MicroRNA (miRNA) sensing strategies employing rolling circle amplification (RCA) coupled with the hairpin DNA (HD) probe-mediated FRET assay have shown promise, but achieving rapid, sensitive, and specific detection of target miRNA remains a challenge in clinical diagnostics. Herein, we incorporate PstI endonuclease cleavage (PEC) into a conventional RCA-based HD probe FRET assay to develop an effective and feasible method. Long single-stranded RCA products are synthesized from miRNA-21 loaded on a circular dumbbell DNA, and the resultant RCA products self-assemble to generate long HD structures with double-stranded stem regions that are specifically recognized and cleaved by PstI endonucleases when incubated with PstI enzymes.

Self-assembled DNA dendrons as signal amplifiers in a DNA probe-based chemiluminescence assay for enhanced colorimetric detection of short target cDNA.

A simple, reliable, and cost-effective method for nucleic acid detection is of increasing interest in clinical diagnostics of infectious and genetic diseases. Currently, enzyme-mediated methods such as polymerase chain reactions and loop-mediated isothermal amplification are the most widely used methods in the qualitative and quantitative diagnosis of long nucleic acid sequences with high sensitivity. However, a high detection sensitivity for short-length sequences remains a significant challenge because it is difficult for the primers to bind to their sequences.

Target DNA- and pH-responsive DNA hydrogel-based capillary assay for the optical detection of short SARS-CoV-2 cDNA.

DNA is recognized as a powerful biomarker for clinical diagnostics because its specific sequences are closely related to the cause and development of diseases. However, achieving rapid, low-cost, and sensitive detection of short-length target DNA still remains a considerable challenge. Herein, we successfully combine the catalytic hairpin assembly (CHA) technique with capillary action to develop a new and cost-effective method, a target DNA- and pH-responsive DNA hydrogel-based capillary assay, for the naked eye detection of 24 nt short single-stranded target DNA.

Catalytic hairpin DNA assembly-based chemiluminescent assay for the detection of short SARS-CoV-2 target cDNA.

Colorimetric sensors are recognized as a promising means for target molecule detection as they provide rapid, cost-effective, and facile sensing visible to the naked eye. Challenges remain though in terms of their detection sensitivity and specificity for short-length target genes. Herein, we demonstrate the successful combination of the catalytic hairpin DNA assembly (CHA) approach with enzyme-linked immunosorbent assay (ELISA)-mimicking techniques for a simple, sensitive, and sequence-specific colorimetric assay to detect short SARS-CoV-2 target cDNA.