A rapid and facile immunoassay for C-reactive protein using PDMS-based digital magnetofluidics

Area of Science:

• Biomarker Discovery and Diagnostics
• Microfluidics and Lab-on-a-Chip Technologies
• Immunochemical Assays

Background:

• C-reactive protein (CRP) is a key biomarker for inflammation, tissue damage, and cardiovascular disease prediction.
• Traditional enzyme-linked immunosorbent assays (ELISAs) for CRP are time-consuming due to diffusion-limited mass transport.
• There is a need for rapid, facile, and efficient immunoassay methods for CRP analysis.

Purpose of the Study:

• To develop and validate a rapid magnetofluidic immunoassay for C-reactive protein (CRP) detection.
• To leverage a polydimethylsiloxane (PDMS) based magnetofluidic platform for enhanced immunoassay performance.
• To demonstrate the feasibility of a sandwich ELISA format on a microfluidic device for expedited CRP analysis.

Main Methods:

• A polydimethylsiloxane (PDMS) based magnetofluidic device was utilized for droplet manipulation.
• Superhydrophobic properties of PDMS enabled precise control of reagent and sample droplets via an external magnet.
• Magnetic beads functionalized with capture antibodies facilitated immunomagnetic separation (IMS) and droplet transport, accelerating assay steps.

Main Results:

• The magnetofluidic immunoassay successfully detected CRP within 1 hour.
• Achieved a limit of detection of 0.015 mg/L within a concentration range of 0.1-10 mg/L.
• Demonstrated high accuracy and precision with recovery rates of 90-114% and %RSD < 5% in human serum.

Conclusions:

• Magnetofluidic droplet control enables rapid and simplified execution of multi-step immunoassays.
• The microfluidic format conserves reagents and samples while enhancing assay kinetics.
• This approach presents a promising rapid, facile, and cost-effective alternative for various immunoassay applications.