Optofluidic flow meter for sub-nanoliter per minute flow measurements

Area of Science:

• Microfluidics
• Optofluidics
• Flow Measurement

Background:

• Microfluidic systems require precise measurement and control at micro- and nanoscales.
• Emerging applications demand increasingly lower volumetric flow rates.

Purpose of the Study:

• To improve an optofluidic system for measuring and calibrating microflows down to the sub-nanoliter per minute range.
• To enhance real-time flow rate determination in microfluidic channels.

Main Methods:

• Utilizing an optofluidic system for excitation light delivery and fluorescence recording.
• Employing a photobleaching fluorescence emission scaling relationship for flow rate determination.
• Calibrating flow controllers and optimizing measurement resolution using molecules with reduced diffusion coefficients.

Main Results:

• Achieved improved calibration of a flow controller to 1% uncertainty.
• Demonstrated an optofluidic flow meter resolution of less than 1 nL/min with 5% uncertainty.
• Utilized a molecule with a 14-fold smaller diffusion coefficient for enhanced resolution.

Conclusions:

• Established new capabilities in sub-nanoliter per minute flow control and measurement.
• Highlighted the generalizability of these advancements to light-material interaction and molecular diffusion.
• Emphasized the potential impact on chemical and biomedical industries.