Bar-coded hydrogel microparticles for protein detection: synthesis, assay and scanning.

Area of Science:

• Biotechnology
• Materials Science
• Analytical Chemistry

Background:

• Multiplexed protein detection is crucial for biological research and diagnostics.
• Existing methods often face challenges with sensitivity, nonfouling properties, and high-throughput analysis.
• Hydrogel microparticles offer a promising platform for sensitive bioassays.

Purpose of the Study:

• To describe a protocol for fabricating bar-coded hydrogel microparticles for multiplexed protein detection.
• To establish a rapid microfluidic scanning method for analyzing these particles.
• To demonstrate the utility of these particles for sensitive and quantitative protein measurements.

Main Methods:

• Fabrication of poly(ethylene glycol)-based hydrogel microparticles using microfluidic flow lithography.
• Incorporation of unique graphical bar codes and antibody probes within distinct particle regions.
• Development of an antibody sandwich assay for protein capture and labeling.
• High-throughput microfluidic scanning for bar code detection and target quantification.

Main Results:

• Reproducible synthesis of bar-coded hydrogel microparticles at a rate of 16,000 particles/hour.
• Protein detection assay completed in 3-4 hours with high sensitivity (as low as 1 pg/mL).
• Microfluidic scanning achieved detection rates of 25 particles/second.
• Demonstrated a three-log dynamic range for protein quantification.

Conclusions:

• The developed protocol provides a sensitive, nonfouling, and bio-inert suspension array for multiplexed protein measurement.
• Bar-coded hydrogel microparticles enable customizable panels for detecting multiple protein targets efficiently.
• This technology facilitates rapid and quantitative analysis of low-abundance protein biomarkers.