An Immunosensing System Using Stilbene Glycoside as a Fluorogenic Substrate for an Enzymatic Reaction Model

Area of Science:

• Biochemistry
• Analytical Chemistry
• Biosensors

Background:

• Horseradish peroxidase (HRP) is widely used in immunoassays.
• Development of novel fluorogenic substrates can enhance assay sensitivity and efficiency.
• Natural products offer potential for new biosensing applications.

Purpose of the Study:

• To evaluate stilbene glycoside (TBG) as a fluorogenic substrate for HRP.
• To develop and assess an enzyme-linked immunosensing system using TBG.
• To compare TBG with existing HRP substrates.

Main Methods:

• TBG was tested as a substrate for HRP-catalyzed reactions.
• A competitive immunoassay was designed using HRP-conjugated Brucella melitensis antibody (HRP-BrAb) and immobilized antigen (BrAg).
• The immunosensing system utilized a graphite-based electrode modified with BrAg and HRP-BrAb.

Main Results:

• TBG demonstrated effective HRP detection, catalyzing a fluorogenic reaction with H₂O₂.
• The enzyme-linked immunosensing system showed a linear detection range of 3.5´10⁻⁸~7.6´10⁻⁶ g/L for Brucella melitensis antibody.
• A low detection limit of 1.7´10⁻⁹ g/L was achieved, with good reproducibility (RSD=3.8%) and regenerable sensing surface.

Conclusions:

• Stilbene glycoside (TBG) is a viable and effective fluorogenic substrate for HRP.
• The developed HRP-based immunosensing system using TBG is sensitive and reproducible.
• TBG offers a promising alternative for fluorometric enzyme-linked immunosensing applications, including clinical diagnostics.