Vertical flow immunoassay (VFA) biosensor for a rapid one-step immunoassay

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Immunotechnology

Background:

• High sensitivity C-reactive protein (hsCRP) is a crucial biomarker for inflammation.
• Existing immunoassay methods can be time-consuming or lack sensitivity.
• Rapid and accurate hsCRP detection is vital for timely clinical diagnosis.

Purpose of the Study:

• To develop a highly rapid, one-step immunoassay for hsCRP detection.
• To utilize a vertical flow immunoassay (VFA) biosensor for enhanced sensitivity and speed.
• To compare the performance of the VFA biosensor with traditional lateral flow assay (LFA) systems.

Main Methods:

• Development of a VFA biosensor comprising stacked sample pad, conjugate pad, FTH film, and nitrocellulose (NC) membrane.
• Immobilization of anti-hsCRP and secondary antibodies on the NC membrane.
• Conjugation of anti-hsCRP antibodies with gold nanoparticles (AuNPs) in the conjugate pad.
• Optimization of assay conditions, including hole size and sample volume.
• Detection of hsCRP using the optimized VFA biosensor.

Main Results:

• The VFA biosensor detected hsCRP concentrations ranging from 0.01 to 10 μg mL(-1) within 2 minutes.
• The assay demonstrated a gradual, concentration-dependent signal increase.
• The VFA system exhibited no hook effect within the tested concentration range.
• Performance comparison showed advantages over traditional LFA systems.

Conclusions:

• A highly rapid and sensitive VFA biosensor for hsCRP detection has been successfully developed.
• The VFA biosensor offers a significant improvement in detection speed and performance compared to LFA.
• This technology holds promise for point-of-care diagnostics and rapid inflammation monitoring.