Mesoporous silica-modified upconversion biosensor coupled with real-time ion release properties for ultrasensitive detection of Staphylococcus aureus in meat

Staphylococcus aureus (S. aureus) is a pathogenic bacterium that can cause serious contamination in meat. Herein, a novel fluorescence biosensor was designed for the rapid detection of S. aureus based on mesoporous silica-modified upconversion nanoparticles (UCNPs-mSiO2). Particularly, the mesoporous silica (MS) was introduced to empower the biosensor with hydrophilic and ion loading capabilities. The results showed that the introduction of S. aureus in the system led to the discharge of Fe2+ ions by binding to the molecular gating (aptamer) of mesoporous channels. The oxidation of Fe2+ to Fe3+ in the presence of hydrogen peroxide, resulted in quenching of the fluorescence of UCNPs. Remarkably, the prepared biosensor achieved low detection limits of 25 CFU/mL and a wide detection range of 63–6.3 × 106 CFU/mL. The recovery of S. aureus in meat was 91–93% (pork) and 96–105% (beef), which exhibited insignificant difference compared with the traditional plate counting method. Consequently, with its advantages of sensitivity and speed, the developed biosensor can be a promising platform for S. aureus detection in meat.