A Guide to Quantitative Biomarker Assay Development using Whispering Gallery Mode Biosensors

Area of Science:

• * Photonics and Sensor Technology
• * Analytical Chemistry
• * Biomolecular Detection

Background:

• * Whispering gallery mode (WGM) sensors detect analytes by measuring changes in local refractive index.
• * Chip-integrated silicon photonic devices offer robust fabrication and multiplexed array capabilities.
• * WGM sensors have demonstrated low detection limits for biomolecular targets in various assay formats.

Purpose of the Study:

• * To describe a generalizable protocol for developing quantitative, multiplexed immunoassays.
• * To utilize silicon photonic microrings as a WGM sensing platform.
• * To enable sensitive and specific detection of biomolecular targets.

Main Methods:

• * Functionalization of silicon photonic microrings with target-specific capture agents.
• * Measurement of analyte binding via changes in local refractive index.
• * Development of enzymatically enhanced sandwich immunoassays for amplified detection.

Main Results:

• * Achieved sub-picomolar detection limits for multiple cytokines.
• * Demonstrated high analyte specificity suitable for complex clinical matrices.
• * Validated the use of silicon photonic microrings for quantitative, multiplexed immunoassays.

Conclusions:

• * The presented protocol provides a generalizable approach for WGM-based immunoassay development.
• * Silicon photonic microring platforms are effective for sensitive and specific biomolecular detection.
• * This method facilitates the creation of multiplexed sensor arrays for diverse analytical applications.