One-Step Immunoassay for Biomarker Quantification in Complex Mixtures Based on Phase-Separated Antifouling...

Area of Science:

• Biomolecular detection
• Polymer chemistry
• Assay development

Background:

• Detecting target biomolecules in complex biological fluids is challenging due to nonspecific adsorption and low analyte concentrations.
• Existing immunoassay methods often require multiple steps, including washing, which can be time-consuming and reduce efficiency.

Purpose of the Study:

• To develop a novel one-pot sandwich immunoassay (oneSTEP) for efficient and specific detection of biomolecules.
• To utilize programmable zwitterionic polymer coacervates for analyte recruitment and signal amplification.
• To enable rapid, wash-free detection with high specificity and signal-to-noise ratio.

Main Methods:

• Development of programmable zwitterionic polymer coacervates for selective analyte capture.
• Implementation of a one-pot, wash-free sandwich immunoassay format (oneSTEP).
• Fluorescence-based readout using standard microscopy and flow cytometry.

Main Results:

• Demonstrated ultralow nonspecific adsorption of target analytes by the coacervates.
• Achieved rapid, wash-free detection with high specificity and signal-to-noise ratio.
• Successfully detected complement component 5 in human serum and SARS-CoV-2 spike protein in artificial saliva with a 300 pM limit of detection.

Conclusions:

• The oneSTEP assay provides a sensitive and specific method for detecting biomolecules in complex biological samples.
• This approach offers advantages over traditional bead-based immunoassays for high-throughput screening and clinical diagnostics.
• Programmable zwitterionic polymer coacervates show significant potential for advancing immunoassay technologies.