Target-initiated DNA release-directed catalytic hairpin assembly-based ultrasensitive cyclic amplification sensor detection of serum miRNA.

MicroRNAs (miRNAs) are important biomarkers for a variety of diseases. Here, we developed an enzyme-assisted cyclic amplification strategy for an electrochemical method based on a highly sensitive and target-specific catalytic hairpin assembly (CHA) reaction for trace miRNA detection in serum. The miRNA periodically triggers the hairpin probes (H1, H2) to form a three-way structure of DNA through the CHA reaction, which is accompanied by the release of single-stranded DNA (ssDNA1) and miRNA.

Target-triggered hybridization chain reaction for ultrasensitive dual-signal miRNA detection.

A signal amplification sensing system with target-triggered DNA cascade reaction combined with dual-signal readout technology was designed for ultrasensitive analysis of miRNA. The highly conductive metal organic frameworks (MOFs) derivative, N-doped carbon dodecahedron (N-PCD) was deposited with gold nanoparticles as the electrode substrate, which could assist the electron transfer between the molecular probe and the electrode surface, and could remarkably enhance electrochemical response. Tetrahedral DNA nanostructure (T4-DNA) with high structural stability and mechanical stiffness was designed to improve the loading capacity and binding efficiency of the target, thus increasing the sensitivity of the system.

Aptamer Embedded Arch-Cruciform DNA Assemblies on 2-D VS Scaffolds for Sensitive Detection of Breast Cancer Cells.

Arch-cruciform DNA are self-assembled on AuNPs/VS scaffold as a highly sensitive and selective electrochemical biosensor for michigan cancer foundation-7 (MCF-7) breast cancer cells. In the construction, arch DNA is formed using two single-strand DNA sequences embedded with the aptamer for MCF-7 cells. In the absence of MCF-7 cells, a cruciform DNA labeled with three terminal biotin is bound to the top of arch DNA, which further combines with streptavidin-labeled horseradish peroxidase (HRP) to catalyze the hydroquinone-HO reaction on the electrode surface.