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Circle-to-circle amplification on a digital microfluidic chip for amplified single molecule detection
Malte Kühnemund1, Daan Witters, Mats Nilsson
1Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Box 815, 751 08 Uppsala, Sweden.
Lab on a Chip
|June 18, 2014
Summary
This study introduces a novel digital microfluidic assay for DNA detection using padlock probes and isothermal circle-to-circle amplification (C2CA). The method achieves high sensitivity for infectious disease diagnostics, detecting as low as 1 aM synthetic Pseudomonas aeruginosa DNA.
Area of Science:
- Biotechnology
- Molecular Diagnostics
- Microfluidics
Background:
- Digital nucleic acid detection methods often require complex microfabrication.
- Integrating multi-step assays and achieving single-molecule detection presents challenges.
Purpose of the Study:
- To develop a novel digital microfluidic nucleic acid amplification concept.
- To enable sensitive and efficient DNA detection for infectious disease diagnostics.
Main Methods:
- Utilized digital microfluidics for droplet manipulation and magnetic particle handling.
- Employed padlock probes for target-dependent DNA circularization.
- Implemented isothermal circle-to-circle amplification (C2CA) for signal amplification.
- Developed an optimized particle extraction and transfer protocol for high efficiency.
Main Results:
- Achieved nearly 100% extraction efficiencies for superparamagnetic particles.
- Demonstrated compartmentalization for digital detection using molecular biology, avoiding complex microfabrication.
- Generated hundreds of DNA nanospheres per target molecule via C2CA.
- Detected synthetic Pseudomonas aeruginosa DNA down to 1 aM with a 4-log linear dynamic range.
- Showcased comparable C2CA product yields to off-chip controls, indicating high assay performance.
Conclusions:
- The integrated digital microfluidic C2CA platform offers a sensitive and efficient method for nucleic acid detection.
- This approach circumvents complex microfabrication, simplifying digital detection.
- The assay demonstrates excellent suitability for infectious disease diagnostics due to its high sensitivity and dynamic range.
