Electrochemical coding for multiplexed immunoassays of proteins

Area of Science:

• Electrochemistry
• Nanotechnology
• Biotechnology

Background:

• Multiprotein detection is crucial for diagnostics.
• Existing methods may lack sensitivity or multiplexing capabilities.
• Nanomaterials offer unique properties for biosensing.

Purpose of the Study:

• To develop a simultaneous electrochemical immunoassay for multiple proteins.
• To utilize inorganic nanocrystal tracers for distinct signal generation.
• To achieve high sensitivity and minimize non-specific binding.

Main Methods:

• Developed a sandwich immunoassay using antibody-functionalized magnetic beads and nanocrystal tracers.
• Employed carbamate linkage for conjugating nanocrystals with antibodies.
• Utilized electrochemical stripping transduction for signal amplification.
• Demonstrated simultaneous detection of four proteins (beta(2)-microglobulin, IgG, BSA, CRP) using ZnS, CdS, PbS, and CuS nanocrystals.

Main Results:

• Achieved femtomole (fmol) detection limits.
• Each protein generated a unique voltammetric peak, correlating with identity and concentration.
• Demonstrated successful simultaneous detection of four model proteins.
• Nanocrystal labels exhibited comparable sensitivity.

Conclusions:

• The developed electrochemical immunoassay enables simultaneous protein quantification with high sensitivity.
• The use of distinct inorganic nanocrystal tracers provides electrochemical coding for multiplexing.
• This approach holds promise for scalable protein diagnostics and biosecurity applications.