A cell-based sensor of fluid shear stress for microfluidics

Area of Science:

• Biotechnology
• Cell Biology
• Microfluidics

Background:

• Microfluidic devices for cell studies require fluid handling, which generates fluid shear stress (FSS).
• Existing methods for assessing FSS impact on cells (e.g., viability, morphology) lack specificity and quantitative metrics.
• A direct method to evaluate FSS physiological implications in microfluidic systems is needed.

Purpose of the Study:

• To develop the first genetically encoded cell sensors for quantitative measurement of FSS pathway activation.
• To create a transcriptional sensor in NIH3T3 cells based on FSS-induced Early Growth Factor-1 (EGF-1) upregulation.
• To validate the sensor's specificity, functionality, and sensitivity to varying FSS conditions.

Main Methods:

• Engineered NIH3T3 cells with a transcriptional sensor detecting Early Growth Factor-1 (EGF-1) gene expression.
• Verified sensor response via microscopy and flow cytometry after chemical induction of the FSS pathway.
• Tested sensor performance across a range of FSS intensities and durations, including within an inertial microfluidic device.

Main Results:

• Demonstrated successful quantitative fluorescence reporting of FSS pathway activation.
• Confirmed sensor specificity and functionality through chemical induction and microscopy/flow cytometry.
• Established a limit of detection of 2 dynes cm⁻² for FSS applied over 30 minutes.
• Showcased sensor sensitivity in a dynamic microfluidic environment.

Conclusions:

• Genetically encoded cell sensors offer a novel, quantitative method to assess FSS in microfluidic systems.
• These sensors can guide the engineering of microsystems with optimized FSS levels.
• The technology enables end-users to evaluate the specific impact of FSS on their cell-based assays.