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Updated: May 23, 2025
Detection and Monitoring of Tumor Associated Circulating DNA in Patient Biofluids
Published on: June 8, 2019
Highly Sensitive Detection of Let-7a in Different Tumor Cells Based on a Dual Cascade Signal Amplification Strategy
Yan Zhang1, Lin Liu1, Chun Mei Li1
1Key Laboratory of Biomedical Analytics (Southwest University), Chongqing Science and Technology Bureau, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, PR China.
Abstract:
Let-7a is a key microRNA (miRNA) cancer biomarker closely associated with cancer diagnosis and treatment, but its detection is challenging due to its small size and low abundance. In this study, we developed a highly sensitive cascade amplification strategy by integrating catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR) to achieve dual-signal amplification. Two functionalized DNA tetrahedron (TDN) probes, TDN-1 and TDN-2 were first assembled by annealing four sequences and modified with four hairpins. Upon activation by let-7a, a cascade reaction occurred through the TDN-1 and TDN-2 probes, generating DNA aggregates through an isothermal CHA-HCR process. Spatial confinement effect played a key role during the CHA-HCR, enabling highly sensitive detection of let-7a while yielding a detection limit of 8.51 pM. This TDN-CHA-HCR reaction was then successfully applied to in situ imaging of endogenous let-7a in living cells, showing great promise in the early diagnosis and treatment of cancers.
Insights
We developed a sensitive DNA probe method for detecting let-7a, a key microRNA cancer biomarker. This new approach enables highly accurate cancer diagnosis and treatment monitoring in living cells.
Area of Science:
- Biochemistry
- Molecular Biology
- Nanotechnology
Background:
- Let-7a is a crucial microRNA (miRNA) biomarker for cancer diagnosis and treatment.
- Detecting let-7a is difficult due to its small size and low concentration.
Purpose of the Study:
- To develop a highly sensitive detection strategy for let-7a.
- To enable in situ imaging of endogenous let-7a in living cells for cancer research.
Main Methods:
- Integrated catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR) for dual-signal amplification.
- Utilized functionalized DNA tetrahedron (TDN) probes (TDN-1 and TDN-2) in a cascade reaction.
- Leveraged spatial confinement effects within the CHA-HCR process for enhanced sensitivity.
Main Results:
- Achieved a highly sensitive detection limit of 8.51 pM for let-7a.
- Successfully generated DNA aggregates through an isothermal CHA-HCR process.
- Demonstrated successful in situ imaging of endogenous let-7a in living cells.
Conclusions:
- The developed TDN-CHA-HCR strategy offers a promising tool for sensitive let-7a detection.
- This method shows potential for early cancer diagnosis and treatment monitoring.
- In situ imaging in living cells opens new avenues for cancer research.
