A rapid portable assay for Salmonella typhimurium quantitative detection based on performance-enhancing anti-matrix...

Area of Science:

• Biotechnology and Biosensing
• Food Safety and Public Health

Background:

• Salmonella typhimurium is a significant cause of foodborne illness globally, necessitating rapid, portable, and sensitive detection methods.
• Existing aptamer-based detection methods for S. typhimurium face challenges in sensitivity, portability, and quantification accuracy for field applications.

Purpose of the Study:

• To optimize aptamer binding properties for enhanced affinity and matrix interference resistance.
• To develop a novel, signal-amplified, portable aptamer assay for quantitative S. typhimurium detection.
• To enable real-time, on-site detection of S. typhimurium using accessible instrumentation.

Main Methods:

• Employed truncation strategies to optimize the S. typhimurium aptamer ROU-77, resulting in the high-affinity aptamer ROU-46.
• Designed a novel variant probe integrating the truncated aptamer and DNA bridges for signal amplification.
• Utilized a portable glucose meter to quantify target concentration via glucose level conversion.

Main Results:

• The truncated aptamer ROU-46 showed a 4.2-fold increase in target affinity compared to ROU-77.
• The developed assay achieved a sensitive detection limit of 295 CFU·mL⁻¹ for S. typhimurium.
• Demonstrated excellent specificity, reproducibility, and practical applicability of the portable detection method.

Conclusions:

• Successfully optimized aptamer affinity and matrix resistance, providing a novel aptamer optimization strategy.
• Developed an innovative on-site detection method for S. typhimurium by integrating aptamers with a portable glucose meter.
• The portable quantification device facilitates real-time, rapid detection, eliminating the need for large-scale equipment.