Multiple amplification-based fluorometric aptasensor for highly sensitive detection of Staphylococcus aureus

Area of Science:

• Biosensing and diagnostics
• Nanotechnology in medicine
• Bacterial detection and identification

Background:

• Accurate detection of Staphylococcus aureus (S. aureus) is crucial for food safety, environmental monitoring, and clinical diagnostics.
• Preventing the spread of antibiotic-resistant bacteria necessitates rapid and reliable identification methods.
• Existing methods may lack the sensitivity, specificity, or speed required for certain applications.

Purpose of the Study:

• To develop a fluorometric aptasensor for ultra-sensitive, specific, and rapid detection of S. aureus.
• To leverage magnetic nanoparticles (MNPs) and a multi-probe amplification strategy for enhanced signal generation.
• To validate the aptasensor's performance in complex matrices like blood samples.

Main Methods:

• Design of a fluorometric aptasensor utilizing aptamers for S. aureus recognition.
• Integration of magnetic nanoparticles (MNPs) for sample enrichment and separation.
• Employment of a biotin-streptavidin system and four FAM-labeled partially complementary DNA sequences (FAM-pcDNAs) for signal amplification.
• Quantification of S. aureus by measuring fluorescence intensity of released FAM-pcDNAs.

Main Results:

• The aptasensor demonstrated high specificity and ultra-high sensitivity with a limit of detection (LOD) of 1.23 CFU/mL.
• A wide linear detection range from 1 to 10^8 CFU/mL was achieved.
• The assay provided rapid detection results in approximately 1.5 hours and showed successful detection in spiked blood samples.

Conclusions:

• The developed fluorometric aptasensor provides a highly sensitive, specific, and rapid method for S. aureus detection.
• The multiple amplification strategy significantly enhances detection capabilities.
• This aptasensor platform holds promise for practical, high-performance biosensing applications in bacterial detection.