3D mapping of microfluidic flow in laboratory-on-a-chip structures using optical tweezers

Area of Science:

• Fluid Dynamics
• Microfluidics
• Biophysics

Background:

• Accurate flow measurement is crucial for microfluidic systems, impacting lab-on-a-chip device understanding and computational model validation.
• Current methods face challenges in precision and invasiveness when analyzing complex flow fields.

Purpose of the Study:

• To develop and validate a minimally invasive optical tweezer method for precise 2D and 3D flow field velocity vector measurement in microfluidic systems.
• To compare experimental flow field data with computational fluid dynamics (CFD) models.

Main Methods:

• Utilized optical tweezers within a microfluidic setup to track particle movement and determine velocity vectors.
• Measured flow fields in two and three dimensions around microstructures, including molded channel features and biological cells.
• Compared experimental data against a complex fluid dynamics model.

Main Results:

• Achieved agreement between experimental measurements and CFD model simulations with an error of less than 3 microm/s.
• Demonstrated high reproducibility of the optical tweezer measurement technique.
• Confirmed the minimally invasive nature of the method.

Conclusions:

• Optical tweezers provide a highly accurate, reproducible, and minimally invasive method for microfluidic flow field characterization.
• This technique validates computational simulations and enhances understanding of flow dynamics in lab-on-a-chip devices.
• Future applications include in-depth rheological studies of biological cells and microstructures.