Quantitative 3-dimensional profiling of channel networks within transparent lab-on-a-chip microreactors using a...

Area of Science:

• Microfluidics
• Analytical Chemistry
• Optical Metrology

Background:

• Lab-on-a-chip (LOC) devices are crucial for miniaturized chemical analysis.
• Accurate characterization of microchannel dimensions is essential for LOC device optimization.
• Existing 3D profiling methods can be complex or destructive.

Purpose of the Study:

• To develop a quantitative, non-destructive 3D profiling method for microchannel networks in transparent LOC devices.
• To establish a method for accurate measurement of channel dimensions.
• To investigate the impact of fabrication parameters on channel profiles.

Main Methods:

• Utilizing digitized microscope images of dye-filled microchannels.
• Employing transmission mode microscopy with narrow bandpass filtered light.
• Applying Beer-Lambert law to convert absorbance data to optical path length for 3D reconstruction.

Main Results:

• Achieved quantitative 3D profiling of micron-sized channel networks.
• Demonstrated measurement accuracy of a few percent for channel depths (10-500 µm).
• Obtained lateral spatial resolution below 1 µm with insignificant refractive index mismatch distortion.

Conclusions:

• The developed method offers a convenient, accurate, and non-destructive approach for microchannel profiling.
• This technique provides essential data for optimizing LOC device performance.
• The method successfully analyzed the effects of thermal bonding and etch time on channel profiles.