A capillary-based microfluidic chip prepared via multiple coating and used for a multiplex immunoassay

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Point-of-Care Diagnostics

Background:

• Point-of-care testing (POCT) demands integrated, portable, and cost-effective diagnostic solutions.
• Traditional microfluidic chips face challenges in fabrication, cost, and cross-contamination for multiplexed assays.
• Antibody array preparation in microchannels often suffers from significant cross-contamination issues.

Purpose of the Study:

• To develop a capillary-based microfluidic chip for multiplexed immunoassays.
• To overcome the limitations of traditional microfluidic chips in POCT.
• To enable simple, low-cost, and batch-producible fabrication for portable diagnostics.

Main Methods:

• Fabrication of a capillary-based microfluidic chip using a multiple coating technique.
• Creation of antibody arrays by sequential blocking and conjugation along the capillary's inner surface.
• Experimental validation and theoretical derivation to quantify cross-contamination between antibodies.

Main Results:

• Achieved less than 5% cross-contamination between capture antibodies along the capillary.
• Demonstrated multiplexed detection of cardiac biomarkers: myoglobin, cardiac troponin I, and creatine kinase-MB.
• Established limits of detection at 1.0 ng/mL (myoglobin), 0.5 ng/mL (cardiac troponin I), and 1.0 ng/mL (creatine kinase-MB).

Conclusions:

• The developed capillary-based microfluidic chip is suitable for multiplexed immunoassays with minimal cross-contamination.
• The fabrication method is compatible with batch production, offering a low-cost and simple approach.
• This technology shows significant promise for portable, affordable POCT of acute diseases.