Signal amplification for DNA detection based on the HRP-functionalized Fe3O4 nanoparticles

Area of Science:

• Electrochemistry
• Nanotechnology
• Biotechnology

Background:

• Sensitive detection of sequence-specific DNA is crucial for diagnostics.
• Nanomaterials offer unique properties for biosensor development.
• Electrochemical methods provide sensitive and label-free detection capabilities.

Purpose of the Study:

• To develop a sensitive electrochemical DNA biosensor.
• To utilize horseradish peroxidase (HRP) and magnetic nanoparticles (Fe(3)O(4) NPs) for signal amplification.
• To construct a sandwich-type DNA biosensor for enhanced detection.

Main Methods:

• Fabrication of HRP-functionalized Fe(3)O(4) NPs using layer-by-layer (LbL) technique.
• Immobilization of signal and diluting probes on Au NPs, creating DNA-Au-HRP-Fe(3)O(4) (DAHF) bioconjugates.
• Assembly of DAHF bioconjugates onto a gold nanofilm (GNF) modified electrode for biosensor construction.
• Electrochemical characterization using cyclic voltammetry (CV), chronoamperometry (i-t), and electrochemical impedance spectroscopy (EIS).

Main Results:

• The biosensor demonstrated sensitive detection of target DNA down to 0.7 fmol.
• A wide dynamic range spanning 4 orders of magnitude was achieved.
• Excellent discrimination against two-base mismatched and non-complementary DNA sequences was observed.

Conclusions:

• The developed electrochemical DNA biosensor offers high sensitivity and specificity.
• The combination of HRP, magnetic nanoparticles, and Au NPs enhances signal amplification.
• This approach provides a promising platform for sequence-specific DNA detection.