Layer-by-layer electrochemical biosensor with aptamer-appended active polyelectrolyte multilayer for sensitive...

Area of Science:

• Electrochemistry
• Biosensors
• Nanomaterials

Background:

• Label-free electrochemical aptasensors offer sensitive protein detection.
• Layer-by-layer (LBL) self-assembly provides a versatile platform for sensor fabrication.
• Ferrocene-appended poly(ethyleneimine) (Fc-PEI) and carbon nanotubes (CNTs) enhance electrochemical signals.

Purpose of the Study:

• To develop simple, label-free electrochemical aptasensors for protein detection.
• To utilize LBL self-assembled multilayers incorporating Fc-PEI, CNTs, and aptamers.
• To demonstrate the sensitivity, selectivity, stability, and generality of the developed sensing strategies.

Main Methods:

• Fabrication of LBL self-assembled multilayers on electrode surfaces via electrostatic interaction.
• Utilizing Fc-PEI, CNTs, and DNA aptamers in the multilayer assembly.
• Monitoring changes in Fc-PEI's differential pulse voltammetry (DPV) signals upon target binding.

Main Results:

• Achieved a wide detection range (0.3-165 ng/mL) and low detection limit (0.14 ng/mL) for thrombin.
• Obtained a wide detection range (0.2 ng/mL to 1.66 µg/mL) and low detection limit (0.17 ng/mL) for lysozyme.
• Demonstrated that target binding creates an electron transfer barrier, decreasing DPV signals.

Conclusions:

• The developed LBL electrochemical aptasensor strategies are effective for label-free protein detection.
• The sensors exhibit high sensitivity, selectivity, stability, and broad applicability.
• This approach offers a promising platform for sensitive and reliable protein analysis.