Droplet-Based Preparation of ZnO-nanostructure Array for Microfluidic Fluorescence Biodetection

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Nanostructure-enhanced biodetection is crucial for early cancer diagnosis and treatment.
• Zinc oxide (ZnO) nanostructures offer excellent biocompatibility and fluorescence enhancement for sensitive cancer biomarker detection.
• Existing fluorescence detection methods require optimization for high sensitivity, multiplexing, and user-friendliness.

Purpose of the Study:

• To develop a simple droplet microfluidic chip for in situ, patterned growth of ZnO nanostructures.
• To investigate the controlled growth of ZnO nanostructures within static droplets.
• To demonstrate the application of patterned ZnO nanostructures in multiplexed fluorescence immunoassay for cancer biomarkers.

Main Methods:

• Fabrication of a simple droplet microfluidic chip for static droplet arrays.
• In situ growth of ZnO nanostructures by controlling growth time and replenishment intervals.
• Application of patterned ZnO nanostructures for fluorescence immunoassay of cancer biomarkers (human α-fetoprotein and carcinoembryonic antigen).

Main Results:

• Successful patterned growth of ZnO nanostructures with varied diameters in static droplets.
• Achieved low limits of detection for cancer biomarkers: 138 fg/mL for human α-fetoprotein and 218 fg/mL for carcinoembryonic antigen.
• Demonstrated a wide dynamic range of 8 orders for biomarker detection.

Conclusions:

• The developed droplet microfluidic device offers a novel approach for patterned ZnO nanostructure growth.
• This platform provides guidance for designing multiple fluorescence amplification systems for biosensing.
• The multifunctional microfluidic devices show potential as efficient tools for fluorescence-based cancer diagnostic assays.