A High Aspect Ratio Bifurcated 128-Microchannel Microfluidic Device for Environmental Monitoring of Explosives

Area of Science:

• Analytical Chemistry
• Chemical Engineering
• Biotechnology

Background:

• Developing sensitive explosives detection platforms is crucial for security.
• Microfluidic devices offer unique advantages for chemical analysis due to their small scale and controlled environments.
• High aspect ratio microchannels can enhance assay performance by optimizing interactions.

Purpose of the Study:

• To design, fabricate, and integrate a novel bifurcated microfluidic device for trace explosives detection.
• To evaluate the device's performance, particularly its limit of detection (LOD) for 2,4,6-trinitrotoluene (TNT).
• To investigate the fluid dynamics within the microfluidic channels.

Main Methods:

• Fabrication of a bifurcated microfluidic device with 128 high aspect ratio microchannels (40 mm × 40 μm × 250 μm).
• Development of a fluorescence-based displacement immunoassay using a neutravidin-coated biotinylated anti-TNT surface.
• Simulation of fluid flow characteristics using COMSOL Multiphysics to determine Reynolds numbers and pressure.

Main Results:

• Achieved an exceptionally low limit of detection (LOD) of 10 parts-per-trillion (pptr) for TNT.
• Demonstrated improved receptor-target molecule interactions and higher throughput due to high aspect ratio channels (>6:1).
• Calculated low Reynolds numbers (0.27–2.45) and a maximum pressure of 1.2 × 10⁻² psi, indicating efficient fluid handling.

Conclusions:

• The designed bifurcated microfluidic device demonstrates superior sensitivity and efficiency for trace explosives detection.
• High aspect ratio microchannels are effective in enhancing assay performance and enabling ultra-low LODs.
• The device offers durability and versatility for various substrate modifications in detection applications.