Optofluidic membrane interferometer: An imaging method for measuring microfluidic pressure and flow rate...

Area of Science:

• Microfluidics
• Optical Sensing
• Biomedical Engineering

Background:

• Accurate on-chip measurement of microfluidic pressure and flow is crucial for various applications.
• Existing methods often face limitations in cost, fabrication complexity, or dynamic range.

Purpose of the Study:

• To develop and validate a novel, image-based method for simultaneous microfluidic pressure and flow rate sensing.
• To leverage integrated optofluidic membrane interferometers (OMIs) for enhanced sensing capabilities.

Main Methods:

• Fabrication of OMIs using multilayer soft lithography with polydimethylsiloxane (PDMS) and a glass substrate.
• Utilizing a flexible air-gap optical cavity within OMIs to generate pressure-dependent interference patterns.
• Image capture via microscope and analysis using a computer-based pattern recognition algorithm.

Main Results:

• Demonstrated a pressure sensing dynamic range of 0-10 psi with an accuracy of ±2% of full scale.
• Successfully measured microfluidic flow rate by detecting differential pressure across a channel using integrated OMIs.
• OMIs showed advantages in low cost, simple fabrication, large dynamic range, and high sensitivity.

Conclusions:

• The developed image-based OMI method enables simultaneous and accurate measurement of microfluidic pressure and flow rate.
• The technique's compatibility with standard microfluidics allows for easy integration into existing systems for in situ fluid monitoring.
• This approach offers a cost-effective and sensitive solution for microfluidic sensing applications.