Practical High-Performance Lateral Flow Assay Based on Autonomous Microfluidic Replacement on a Film.

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Materials Science

Background:

• Paper-based microfluidic devices offer potential for point-of-care (POC) diagnostics.
• Achieving precise microfluidic control for sensitive assays like ELISA on paper remains challenging.
• Paper's opacity and non-flatness hinder sensitive light-based detection in immunoassays.

Purpose of the Study:

• To develop a novel lateral-flow test chip with enhanced microfluidic control capabilities.
• To improve the sensitivity and accuracy of immunoassays on a paper substrate.
• To overcome the limitations of paper's optical properties for precise detection.

Main Methods:

• Fabrication of a novel lateral-flow test chip by laminating paper, transparent film, and adhesive tape.
• Integration of pump-like fluidic operations (flowing, stopping, solution replacement) controlled by simple solution addition.
• Application of a transparent film to the detection area to enhance optical properties.

Main Results:

• The chip demonstrated high quantitative analysis of C-reactive protein (CRP) in serum, with good correlation at concentrations from 0.1 to 100 ng/mL.
• The novel chip exhibited higher signal intensity and lower variation compared to traditional nitrocellulose membrane chips.
• Achieved a limit of detection of 0.1 ng/mL for CRP, significantly lower than the 100 ng/mL limit of nitrocellulose membranes.

Conclusions:

• The novel lateral-flow test chip facilitates sensitive sandwich immunoassays with simple sample addition.
• The integrated microfluidic control and improved optical properties enhance diagnostic performance.
• This technology holds promise for advanced point-of-care diagnostic applications.