Colorimetric-SERS dual-mode aptasensor for Staphylococcus aureus based on MnO₂@AuNPs oxidase-like activity

Area of Science:

• Nanotechnology
• Biosensing
• Food Safety

Background:

• Nanozyme-linked aptamer-sorbent assay (NLASA) offers rapid screening of aptamer-target interactions.
• Staphylococcus aureus (S. aureus) poses a significant threat to food safety, necessitating sensitive detection methods.

Purpose of the Study:

• To develop a dual-mode colorimetric and SERS sensor for Staphylococcus aureus detection.
• To utilize a MnO2@AuNPs@aptamer (Apt) nanohybrid for enhanced nanozyme activity and specific bacterial capture.

Main Methods:

• Synthesis of MnO2@AuNPs using Cu,Fe-CDs as a reducing agent, imparting oxidase-like and SERS activities.
• Conjugation of S. aureus aptamer to MnO2@AuNPs to create a specific capture probe.
• Development of a dual-mode detection strategy utilizing ABTS oxidation and TMB inhibition for colorimetric and SERS signal generation.

Main Results:

• The developed sensor detected S. aureus in a concentration range of 10^1 to 10^7 CFU/mL.
• Achieved a low detection limit of 0.926 CFU/mL (colorimetric) and 1.561 CFU/mL (SERS).
• Demonstrated high recovery rates (85%-105%) in real food samples.

Conclusions:

• The MnO2@AuNPs@Apt based NLASA provides a sensitive and specific platform for S. aureus detection.
• The dual-mode colorimetric-SERS approach enhances detection reliability and applicability in food safety monitoring.