An aptasensor for staphylococcus aureus based on nicking enzyme amplification reaction and rolling circle...

Area of Science:

• Biotechnology
• Biosensors
• Analytical Chemistry

Background:

• Staphylococcus aureus poses a significant threat in food industries, necessitating sensitive detection methods.
• Existing biosensors often lack the required sensitivity and specificity for accurate S. aureus detection.
• Aptamer-based biosensors offer high specificity but require amplification for ultra-sensitive detection.

Purpose of the Study:

• To develop an ultra-sensitive aptamer-based biosensor for Staphylococcus aureus detection.
• To integrate nicking enzyme amplification reaction (NEAR) and rolling circle amplification (RCA) for enhanced signal amplification.
• To validate the biosensor's specificity, sensitivity, and applicability in food samples.

Main Methods:

• An aptamer-probe (AP) was designed for specific binding to S. aureus.
• Nicking enzyme amplification reaction (NEAR) and rolling circle amplification (RCA) were employed for signal amplification.
• G-quadruplex (G4)/hemin complex formation and its horseradish peroxidase (HRP)-mimic activity were utilized for chemiluminescence detection.

Main Results:

• The biosensor demonstrated specific detection of S. aureus with a linear correlation in the range of 5-10^4 CFU/mL.
• A two-step NEAR-RCA amplification significantly boosted signal output compared to single-cycle amplification.
• The limit of detection (LoD) was as low as 5 CFU/mL.
• The aptasensor effectively discriminated between live and dead S. aureus.

Conclusions:

• The developed aptamer-based biosensor offers ultra-sensitive and specific detection of S. aureus.
• The combination of NEAR and RCA technologies provides a powerful platform for low-level pathogen detection.
• This biosensor shows great potential for application in food industry quality control and safety assurance.