Tetrahedral DNA probe coupling with hybridization chain reaction for competitive thrombin aptasensor

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Thrombin is a key biomarker in hemostasis and thrombosis, making its accurate detection crucial for clinical diagnosis.
• Existing detection methods often lack sensitivity or require complex procedures.
• Development of novel, highly sensitive, and efficient biosensors for thrombin is essential.

Purpose of the Study:

• To develop a novel competitive aptasensor for sensitive thrombin detection.
• To utilize tetrahedral DNA (T-DNA) probes and hybridization chain reaction (HCR) for signal amplification.
• To employ sulfur and nitrogen co-doped reduced graphene oxide (SN-rGO) as a supporting substrate.

Main Methods:

• Preparation of SN-rGO as a biosensor substrate.
• Modification of the electrode with T-DNA probes via Au-S bonds.
• A competitive binding assay between target thrombin and complementary DNA (cDNA).
• Signal amplification using HCR triggered by cDNA-T-DNA hybridization.
• Electrochemical detection using horseradish peroxidase catalysis.

Main Results:

• The aptasensor demonstrated a wide linearity range for thrombin detection from 10^-13 M to 10^-8 M.
• A low detection limit of 11.6 fM (S/N = 3) was achieved.
• The competitive assay design effectively distinguished between thrombin presence and absence.

Conclusions:

• The developed aptasensor offers high sensitivity and a broad detection range for thrombin.
• The combination of SN-rGO, T-DNA, and HCR provides a robust platform for biosensing.
• This novel biosensor shows significant promise for applications in biotechnology and clinical diagnostics.