Efficient AC electrothermal flow (ACET) on-chip for enhanced immunoassays.

Area of Science:

• Biomedical Engineering
• Microfluidics
• Analytical Chemistry

Background:

• Microfluidic biochemical reaction rates are often limited by reagent diffusion, impacting immunoassay sensitivity and detection times.
• AC electrothermal flow (ACET) is used to enhance mass transport and mixing in microfluidic devices.
• Traditional ACET electrode designs create localized mixing, limiting their effectiveness over larger volumes.

Purpose of the Study:

• To introduce a novel ACET electrode design for generating in-plane microfluidic mixing vortices.
• To enhance reagent transport and mixing over large volumes near the reaction surface in microfluidic immunoassays.
• To validate the new design through numerical simulations and experimental studies.

Main Methods:

• Developed and simulated a novel ACET electrode design for in-plane microfluidic mixing.
• Conducted numerical simulations to analyze the effects of reaction kinetics and reagent concentration.
• Performed experimental validation using immunoassays on breast cancer cells to detect HER2 biomarker.

Main Results:

• The novel ACET design generates large-volume in-plane mixing vortices, unlike traditional designs.
• Numerical simulations confirmed the impact of experimental factors on ACET-enhanced surface assays.
• Experiments demonstrated a 6-fold enhancement in assay signal and a 75% reduction in assay time for HER2 detection.

Conclusions:

• The novel ACET electrode design effectively enhances microfluidic mixing for surface-based assays.
• This approach significantly improves immunoassay performance, offering higher sensitivity and faster detection.
• The scalable design holds potential for advanced diagnostic applications, including cancer biomarker detection.