2D Spatially-Resolved Depth-Section Microfluidic Flow Velocimetry Using Dual Beam OCT.

Area of Science:

• Biomedical Engineering
• Optical Physics
• Fluid Dynamics

Background:

• Microfluidic flow analysis traditionally relies on imaging techniques with limitations.
• Existing methods often require multiple access ports or fluorescent tracers.
• There is a need for non-invasive, high-resolution flow measurement in microchannels.

Purpose of the Study:

• To develop and validate a dual beam optical coherence tomography (OCT) instrument for 2D quantitative flow velocity measurements.
• To demonstrate the advantages of dual beam OCT over conventional microscopy-based techniques.
• To present exemplar measurements in microfluidic applications.

Main Methods:

• Development of a dual beam OCT system for rapid particle position re-sampling.
• Implementation of 2D quantitative measurement algorithms for flow velocity.
• Application of the system to microfluidic channels for reference and complex flow studies.

Main Results:

• Demonstrated simultaneous imaging of microfluidic channels with a single optical port.
• Achieved millimetre-deep depth-section velocity profiles, unlike horizontal-section methods.
• Successfully measured Poiseuille flow with 10 µm resolution up to 50 mm/s and analyzed a sloped microfluidic section.

Conclusions:

• Dual beam OCT provides significant advantages for microfluidic flow measurement, including faster flow detection and deeper penetration.
• The developed instrument offers a non-invasive, versatile tool for microscale fluid dynamics research.
• This technique facilitates accurate 2D velocity profiling in complex microfluidic geometries.