Revolutionizing Escherichia coli detection in real samples with digital SERS aptamer sensor technology

Area of Science:

• Nanotechnology
• Biosensing
• Analytical Chemistry

Background:

• Aptamer sensors utilizing surface-enhanced Raman scattering (SERS) show promise for detecting Escherichia coli (E. coli).
• Existing methods require optimization for sensitivity, speed, and precise quantification.

Purpose of the Study:

• To develop and validate a digital SERS aptamer sensor for highly sensitive and rapid quantification of E. coli.
• To integrate ordered nanoscale array synthesis and digital analysis for enhanced bacterial detection.

Main Methods:

• Fabrication of ordered monolayer gold nanosphere arrays (Au NS) on silicon wafers to create uniform "hot spots".
• Utilizing digital SERS for signal uniformity and precise quantification.
• Employing aptamer-DNA base pairing and competitive displacement for E. coli detection.

Main Results:

• The digital SERS aptamer sensor demonstrated excellent selectivity, reproducibility, and a wide linear dynamic detection range (1.0 x 10^1 to 1.0 x 10^9 CFU/ml).
• Achieved a low detection limit of 0.657 CFU/ml.
• Maintained specificity in the presence of mixed bacterial interference, with spiked recoveries ranging from 98.80% to 99.81% in actual samples.

Conclusions:

• The developed digital SERS aptamer sensor enables ultrasensitive, rapid, and precise quantification of E. coli.
• The sensor exhibits high specificity and reliability, suitable for real-world sample analysis.
• This technology holds significant potential for applications in food safety and environmental monitoring.