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Polymer Micropillar Arrays for Colorimetric DNA Detection.
Matthias Geissler1, Lidija Malic1, Keith J Morton1
1Life Sciences Division, National Research Council of Canada, 75 de Mortagne Boulevard, Boucherville, Quebec J4B 6Y4, Canada.
Analytical Chemistry
|April 16, 2020
Summary
Periodic micropillar arrays enable sensitive colorimetric DNA detection of E. coli O157:H7. Microstructure influences signal intensity, with pillar edges playing a key role in assay performance.
Area of Science:
- Biotechnology
- Nanotechnology
- Molecular Diagnostics
Background:
- Colorimetric DNA detection assays are crucial for pathogen identification.
- Microfabrication techniques offer precise control over assay substrates.
- Developing sensitive and spatially controlled DNA detection methods is essential.
Purpose of the Study:
- To utilize periodic micropillar arrays as templates for enhanced colorimetric DNA detection.
- To investigate the influence of micropillar geometry on assay signal intensity and uniformity.
- To develop a microfabricated platform for detecting specific gene markers of *E. coli* O157:H7.
Main Methods:
- Fabrication of periodic micropillar arrays from cyclic olefin copolymer using high-fidelity microfabrication.
- Development of a colorimetric DNA detection assay involving PCR amplification, digoxigenin labeling, and immunoenzymatic detection.
- Utilizing micropillar wicking properties for spatial control of capture probe distribution.
- Investigating geometric parameters (pitch, diameter, height) and their effect on signal intensity.
- Employing absorbance measurements to monitor colorimetric signal kinetics and a theoretical model to simulate molecular accumulation.
Main Results:
- Micropillar arrays facilitate uniform signal distribution and spatial confinement of capture probes.
- Maximum colorimetric signal increase was observed between 20 and 60 minutes.
- Signal intensity is significantly influenced by pillar edges, with deviations from linear relationships at high aspect ratios and densities.
- A theoretical model supports the observed signal variations due to temporal and spatial accumulation of assay components.
Conclusions:
- Periodic micropillar arrays serve as effective templates for spatially controlled, uniform colorimetric DNA detection.
- The geometric characteristics of micropillars, particularly pillar edges, critically impact assay sensitivity.
- This microfabrication approach offers a promising platform for multiplexed and sensitive detection of microbial pathogens like *E. coli* O157:H7.
