Multiplex ELISA in a single microfluidic channel.

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Microfluidics

Background:

• Multiplex enzyme-linked immunosorbent assays (ELISA) are crucial for detecting multiple analytes simultaneously.
• Traditional multiplex ELISA often requires large sample volumes and complex workflows.
• Microfluidic platforms offer potential for miniaturization and improved assay performance.

Purpose of the Study:

• To develop a novel multiplex ELISA within a single microfluidic channel.
• To leverage slow diffusion of enzyme reaction products for multiplexing.
• To reduce sample volume requirements and improve detection limits.

Main Methods:

• A microfluidic device with an array of ELISA regions in a single channel was fabricated.
• Antibodies/antigens were patterned onto assay regions using a flow-based method.
• Analyte capture was performed by incubating a small sample volume (5 μL) under flow conditions.
• The slow diffusion of the enzyme reaction product (resorufin) was exploited for multiplexing.

Main Results:

• Analyte concentration correlated linearly with resorufin generation rate under specific reaction and diffusion time conditions (τ(R) << τ(D)).
• The microfluidic multiplex ELISA achieved a 35% lower limit of detection compared to commercial microtiter plates.
• The assay required only 1/20th of the sample volume used in conventional methods.

Conclusions:

• The developed microfluidic multiplex ELISA is a sensitive and efficient method for simultaneous analyte detection.
• This approach significantly reduces sample consumption and enhances detection sensitivity.
• The strategy of exploiting product diffusion in microfluidic channels opens new avenues for assay development.