Microfluidic Concentration Gradient Chip for Drug Susceptibility

Dean vortex secondary flow mixing for high-throughput biochemical applications

Overview

Microfluidic concentration gradient chip using Dean vortex secondary flow mixing for rapid drug susceptibility testing. Reduces mixing length to 1/3 of traditional methods (12mm → 4mm) via lateral elliptical protrusions on channel sidewalls, enabling high-throughput antimicrobial resistance detection.

Problem Statement

Traditional microbial drug susceptibility testing requires 24-72 hours, large sample volumes, and manual preparation, leading to reproducibility issues and delayed treatment decisions. Concentration gradient variability further complicates accurate MIC (minimum inhibitory concentration) determination.

Methodology

Equivalent Circuit Design

  • Flow resistance in microchannels modeled as electrical circuits (Kirchhoff’s laws)
  • Optimized network creates 6-outlet gradients (C₀=0 to C₅=1)
  • Simplified channel design reduces length and pressure drop

Dean Vortex Mixing

  • Innovation: Semicircular protrusions (50-100 μm radius) on sidewalls generate Dean vortex
  • Efficiency: 1/3 mixing length of straight channels (4mm vs. 12mm)
  • Staggered distribution: Alternating protrusions maximize flow disturbance
  • CFD Validation: Computational fluid dynamics verified concentration distribution

Results

Performance:

  • Mixing length reduced by 67% (12mm → 4mm)
  • 6-level concentration gradients generated
  • Channel dimensions: 50-200 μm width, 50-200 μm depth
  • CFD-validated pressure drop and concentration uniformity

Applications

  • Rapid antimicrobial resistance detection and MIC determination
  • High-throughput drug screening (dose-response analysis)
  • Chemotaxis assays and cell migration studies
  • Enzyme kinetics and protein-ligand binding studies
  • Toxicity evaluation and environmental monitoring

Achievements & Recognition

Patents

Invention Patent (CN112473758A): “Equivalent Circuit Microfluidic Concentration Gradient Chip with Simplified Channel” (Filed Nov 2020, Published Mar 2021, Under examination)

Utility Model Patent (CN214159656U): “Microfluidic Chip Based on Dean Vortex Secondary Flow Mixing” (Filed Nov 2020, Granted Sep 2021)

Publications

Shi, H., Cao, Y., Zhou, Y., et al. “Development and Application of Microfluidic Concentration Gradient Chip.” Chinese Journal of Medical Physics, 2021.

Key Metrics

  • 2 patents filed
  • 67% mixing length reduction
  • 1 peer-reviewed publication

Team & Collaboration

Principal Investigator: A/Prof. Shi Huanhuan (石环环)
Institution: Department of Biomedical Engineering, Nanchang Hangkong University
Core Contributors: Zhou Yanuo (chip design, CFD simulation), Zhang Jiahao (circuit modeling)
Collaborators: Wan Yaru, Lu Enyong, Yuan Lin, Yu Yuehua, Tao Linjie, Cao Y.
Funding: PhD Research Startup Fund (EA202008205)

Timeline

Duration: December 2019 - December 2021 (24 months)