Multi-signal aptasensor for thrombin detection based on catalytically active gold nanoparticles and fluorescent...

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Thrombin is a critical biomarker in clinical diagnostics, necessitating sensitive and reliable detection methods.
• Existing methods for thrombin determination can be complex and expensive, limiting their use in point-of-care settings.
• Development of novel biosensors is crucial for advancing rapid and accessible clinical analysis.

Purpose of the Study:

• To propose a novel multi-signal aptasensor for the quantitative determination of thrombin.
• To utilize catalytically active gold nanoparticles (AuNPs) and fluorescent silicon quantum dots (SiQDs) for enhanced sensing capabilities.
• To develop a cost-effective and user-friendly platform for on-site thrombin detection.

Main Methods:

• Fabrication of an aptasensor using aptamer-modified gold nanoparticles (S1-AuNPs) and SiQDs.
• Exploitation of the catalytic activity of S1-AuNPs to reduce 4-Nitrophenol (4-NP) to 4-Aminophenol (4-AP).
• Utilizing the inner filter effect (IFE) between SiQDs and 4-NP for fluorescence quenching, coupled with colorimetric detection of 4-NP reduction.

Main Results:

• The aptasensor demonstrated dual detection modes: fluorometric and colorimetric.
• Linear detection ranges were established as 0.5-30 nM (fluorometric) and 0.3-30 nM (colorimetric).
• Achieved low limits of detection (LOD) of 0.15 nM (fluorometric) and 0.13 nM (colorimetric), with a portable smartphone-based platform developed.

Conclusions:

• The developed multi-signal aptasensor offers a sensitive and reliable method for thrombin determination.
• The combination of AuNPs and SiQDs provides a synergistic effect for enhanced sensing performance.
• This aptasensor presents a promising tool for on-site clinical diagnostics due to its simplicity, cost-effectiveness, and broad applicability.