Multiplexed Fluoro-electrochemical Single-Molecule Counting Enabled by SiC Semiconducting Nanofilm

Area of Science:

• Analytical Chemistry
• Nanotechnology
• Spectroscopy

Background:

• Ultrasensitive analysis requires high-efficiency, parallel determination of single molecules with accuracy.
• Existing methods face challenges in distinguishing multiple targets simultaneously.

Purpose of the Study:

• To develop a quantitative fluoro-electrochemical imaging approach for direct multiplexed single-molecule counting.
• To achieve high-accuracy determination of different target single molecules in parallel.

Main Methods:

• Utilized a silicon carbide (SiC)-nanofilm-modified indium tin oxide (ITO) transparent electrode.
• Controlled local pH via proton-coupled electron transfer and induced dye oxidation via electrochemical potential.
• Distinguished fluoro-electrochemical responses of single molecules within the same fluorescence channels.

Main Results:

• Achieved non-amplified, direct single-molecule counting with excellent linear responses in the picomolar range.
• Successfully distinguished seven different randomly mixed dyes.
• Demonstrated high accuracy in determining single dye molecules.

Conclusions:

• The proposed fluoro-electrochemical imaging method is versatile and effective for highly accurate single-molecule determination.
• This approach paves the way for highly parallel single-molecule detection across diverse applications.
• Enables simultaneous analysis of multiple targets without amplification.