Related Experiment Video
Updated: Feb 3, 2026

Aptamer-Based Target Detection Facilitated by a 3-Stage G-Quadruplex Isothermal Exponential Amplification Reaction
Published on: October 6, 2022
An aptamer biosensor for leukemia marker mRNA detection based on polymerase-assisted signal amplification and
Meng Zhang1, Fenyue Zhou1, Deqi Zhou2
1Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, 541004, China.
Abstract:
A novel electrochemical luminescence (ECL) aptamer biosensor via polymerase amplification is constructed for label-free detection of leukemia marker mRNA (miR-16). In order to achieve the ultrasensitive detection of the target mRNA, the cyclic target chain displacement polymerization of leukemia marker mRNA assisted with Klenow fragment of DNA polymerase is employed. The determination is carried out by recording the ECL emission of pyridine ruthenium (Ru(bpy)32+) complexes embedded into the assistance DNA (ADNA) loaded on the nanogold surface, after the hybridization reaction between the probe DNA (PDNA) and the remaining sequence of the CP's stem part, and the formation of a core-shell sun-like structure. The mercapto-modified capture DNA (CP) is immobilized on the surface of a magneto-controlled glassy carbon electrode by Au-S bond. The CP is opened and hybridized with the target mRNA to form double-stranded DNA. In the presence of polymerase, primer DNA, and bases (dNTPs), the primer chain gets access to its complementary sequence of the stem part and then triggers a polymerization of the DNA strand, leading to the release of mRNA and starting the next polymerization cycle. Finally, the composite of PDNA-covered and ADNA-covered (embedded with Ru(bpy)32+) gold nanoparticles (hereafter called AuNPs@(PDNA+ADNA-Ru(bpy)32+) is added, and the ECL intensity is recorded. Because of the polymerization cycle and the aggregation of the illuminator of Ru(bpy)32+, the detected signal is amplified significantly. The results showed that the corresponding ECL signal has a good linear relationship with a logarithm of target mRNA concentration in the range of 1 × 10-16 to 1 × 10-7 mol/L, with a detection limit of 4.3 × 10-17 mol/L. The mRNA spiked in the human serum sample is determined, and the recoveries are from 97.2 to 102.0%. This sensor demonstrates good selectivity, stability, and reproducibility. Graphical abstract ᅟ.
More Related Videos
07:59Rapid and Specific Detection of Acinetobacter baumannii Infections Using a Recombinase Polymerase Amplification/Cas12a-based System
Published on: April 25, 2025
09:03Field-Deployable Candidatus Liberibacter asiaticus Detection Using Recombinase Polymerase Amplification Combined with CRISPR-Cas12a
Published on: December 23, 2022
Related Concept Videos
Bacterial RNA Polymerase
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
pre-mRNA Processing
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl...
Translesion DNA Polymerases
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
Chromatin Structure Regulates pre-mRNA Processing
The chromatin structure, especially...
mRNA Stability and Gene Expression
Cis-acting Elements involved in mRNA stability
Nuclear Export of mRNA