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Lensless Fluorescent Microscopy on a Chip
Published on: August 17, 2011
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On-chip light sheet illumination for nanoparticle tracking in microfluidic channels.
Théo Travers1, Gaétan Delhaye1, Martinus H V Werts2
1Laboratoire MOLTECH-Anjou, UMR CNRS 6200, Univ Angers, SFR MATRIX, 2 Bd Lavoisier, 49000 Angers, France. matthieu.loumaigne@univ-angers.fr.
Analytical Methods : Advancing Methods and Applications
|April 3, 2024
Summary
This study presents an inexpensive method using an optical fiber in a microfluidic chip for nanoparticle tracking. This technique enhances signal-to-noise ratio for accurate nanoparticle sizing and dark-field imaging.
Area of Science:
- Microfluidics
- Optical Engineering
- Nanotechnology
Background:
- Accurate nanoparticle tracking and sizing are crucial in various scientific fields.
- Traditional methods for nanoparticle analysis can be complex and costly.
- Integrating efficient illumination into microfluidic systems presents technical challenges.
Purpose of the Study:
- To develop a simple, inexpensive, and efficient method for light sheet illumination in microfluidic chips.
- To enable dark-field microscopic tracking and sizing of nanoparticles.
- To improve the signal-to-noise ratio for nanoparticle analysis.
Main Methods:
- Integration of an optical fiber as a cylindrical lens within a polydimethylsiloxane (PDMS) microfluidic chip.
- Utilizing the optical fiber to shape and homogenize the light sheet illumination.
- Employing calculations, numerical simulations, and experimental measurements to optimize the light sheet configuration.
- Dark-field microscopy for nanoparticle tracking and sizing.
Main Results:
- The optical fiber insertion effectively smoothed PDMS microchannel walls and ensured perpendicular illumination.
- An optimal configuration achieved a slowly converging light sheet with near-uniform axial thickness (12 μm).
- A six-fold increase in signal-to-noise ratio was observed compared to systems without the integrated optical fiber lens.
- Successful tracking and sizing of 80 nm and 50 nm gold nanoparticles were demonstrated.
Conclusions:
- The presented method offers a cost-effective and straightforward approach for advanced nanoparticle analysis.
- Integrating optical fibers as micro-optical components significantly enhances light sheet illumination quality in microfluidics.
- This technique provides a robust platform for precise nanoparticle characterization using dark-field microscopy.
