A sandwich-based evanescent wave fluorescent biosensor for simple, real-time exosome detection^†

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Biosensing

Background:

• Exosomes are crucial biomarkers for noninvasive disease diagnosis and treatment.
• Developing fast, efficient, and sensitive exosome detection methods is vital for medical research.

Purpose of the Study:

• To report a novel sandwich-based evanescent wave fluorescent biosensor (S-EWFB) for exosome detection.
• To establish a rapid, sensitive, and efficient platform for exosome analysis.

Main Methods:

• A two-step strategy utilizing hydrophobic interactions for fluorescent probe binding to exosomes.
• CD63 aptamer-specific capture on an evanescent wave liquid-solid interface for real-time detection.
• Formation of an exosome@fluorescence probe/aptamer sandwich structure for signal amplification.

Main Results:

• Achieved a low detection limit of 7.66 particles/mL for exosomes.
• Established a linear detection range from 47.5 to 4.75 × 10^6 particles/mL.
• Demonstrated a simple, rapid (approx. 1 hour), real-time detection process without requiring separation or purification.

Conclusions:

• The S-EWFB platform offers a highly sensitive and efficient method for exosome detection.
• The biosensor shows excellent surface regeneration and performance in analyzing various exosome types.
• This technology holds significant potential for advancing noninvasive diagnostics and disease monitoring.