Multiplex immunoassays using virus-tethered gold microspheres by DC impedance-based flow cytometry

Area of Science:

• Biomarker detection
• Nanotechnology in diagnostics
• Immunoassay development

Background:

• Multiplex immunoassays require high sensitivity and minimal non-specific adsorption.
• Miniaturization of detection devices is crucial for widespread use.
• Virus-tethered gold microspheres offer unique properties for assay development.

Purpose of the Study:

• To implement virus-tethered gold microspheres for enhanced multiplex immunoassay sensitivity.
• To utilize a DC impedance-based flow cytometer for simultaneous signal detection.
• To demonstrate the system's capability in detecting multiple biomarkers in undiluted human sera.

Main Methods:

• Development of virus-tethered gold microspheres for antibody loading.
• Integration with a chip-based microfluidic flow cytometer for DC impedance and fluorescence detection.
• Simultaneous detection of cardiac troponin I (cTnI), prostate specific antigen (PSA), creatine kinase MB (CK-MB), and myoglobin.

Main Results:

• Virus-tethered microspheres significantly reduced non-specific adsorption.
• Achieved up to a 5.7-fold increase in sensitivity compared to conventional beads.
• Successfully performed multiplex immunoassays for four key biomarkers in undiluted human sera.

Conclusions:

• Virus-tethered gold microspheres provide a promising platform for sensitive multiplex immunoassays.
• The microfluidic flow cytometer enables efficient and simultaneous detection.
• This strategy offers a novel approach for competitive multiplex immunoassay development using suspension arrays.