Binary optical encoding strategy for multiplex assay.

Area of Science:

• Biotechnology
• Nanotechnology
• Analytical Chemistry

Background:

• Multiplex bioassays require advanced encoding strategies for simultaneous detection of multiple analytes.
• Existing methods using single encoding elements like photonic crystal beads (PCBs) or quantum dots (QDs) have limitations in multiplexing capacity.
• Fluorescence immunodetection is a key technique in bioassays, but requires sensitive and specific labeling.

Purpose of the Study:

• To propose and validate a binary optical encoding strategy for enhanced multiplex bioassays.
• To utilize the combined optical spectra of PCBs and QDs for deciphering antigen categories.
• To determine antigen concentrations via fluorescence signals and assess the sensitivity of the proposed method.

Main Methods:

• Developed a binary optical encoding strategy combining PCBs as microcarriers and QDs as fluorescence labels.
• Applied the strategy to fluorescence immunodetection of multiplex antigen molecules.
• Deciphered antigen categories using the binary combination of optical spectra from PCBs and QDs.
• Quantified antigen concentrations based on QD fluorescence intensity.

Main Results:

• Achieved a theoretical multiplexing capacity of m × n, where m and n are the numbers of encoding PCBs and QDs.
• Demonstrated a low-level detection sensitivity of 58 pg/mL for antigens.
• The binary encoding strategy showed superior performance and practicality compared to single-element encoding (PCB or QD alone).

Conclusions:

• The proposed binary optical encoding strategy significantly enhances multiplex bioassay capabilities.
• This approach offers a practical and superior method for antigen detection and quantification in complex biological samples.
• The strategy holds strong potential for widespread application in advanced multiplex bioassays and diagnostics.