1 research outputs found
Three-Mode Electrochemical Sensing of Ultralow MicroRNA Levels
MicroRNAs (miRNAs) are an emerging class of biomarkers
that are
frequently deregulated in cancer cells and have shown great promise
for cancer classification and prognosis. In this work, we developed
a three-mode electrochemical sensor for detection and quantitation
of ultralow levels of miRNAs in a wide dynamic range of measured concentrations.
The sensor facilitates three detection modalities based on hybridization
(H-SENS), p19 protein binding (P-SENS), and protein displacement (D-SENS).
The combined three-mode sensor (HPD-SENS) identifies as low as 5 aM
or 90 molecules of miRNA per 30 μL of sample without PCR amplification,
and can be operated within the dynamic range from 10 aM to 1 μM.
The HPD sensor is made on a commercially available gold nanoparticles-modified
electrode and is suitable for analyzing multiple miRNAs on a single
electrode. This three-mode sensor exhibits high selectivity and specificity
and was used for sequential analysis of miR-32 and miR-122 on one
electrode. In addition, the H-SENS can recognize miRNAs with different
A/U and G/C content and distinguish between a fully matched miRNA
and a miRNA comprising either a terminal or a middle single base mutation.
Furthermore, the H- and P-SENS were successfully employed for direct
detection and profiling of three endogenous miRNAs, including hsa-miR-21,
hsa-miR-32, and hsa-miR-122 in human serum, and the sensor results
were validated by qPCR