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. Shortens the required mixing length to about one third of a conventional channel via protrusions on the channel sidewalls, for microbial drug-susceptibility testing.

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: about 1/3 of the mixing length of a conventional straight channel
  • Staggered distribution: Alternating protrusions maximize flow disturbance
  • CFD Validation: Computational fluid dynamics verified concentration distribution

Results

Performance:

  • Mixing length about 1/3 of a conventional channel
  • 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Circuit Microfluidic Concentration Gradient Chip with Simplified Channel” (Filed Nov 2020, Published Mar 2021, deemed withdrawn Oct 2025; co-inventor, 2nd)

Utility Model Patent (CN214159656U): “Microfluidic Chip Based on Dean Vortex Secondary Flow Mixing” (Filed Nov 2020, Granted Sep 2021, lapsed Nov 2025; co-inventor, 4th)

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
  • Mixing length about 1/3 of a conventional channel
  • 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)