A novel PEG-mediated boric acid functionalized magnetic nanomaterials based fluorescence biosensor for the detection of Staphylococcus aureus

Staphylococcus aureus ( S. aureus ) is one of the pathogens that seriously endanger human health and are widespread in nature. Food poisoning incidents caused by S. aureus frequently break out. Therefore, it is significant that a rapid and accurate method is established for S. aureus detection. In this study, a strategy using magnetic separation combine with fluorescence analysis was proposed for S. aureus detection. Boric acid can selectively enrich compounds with cis -diol groups through a reversible esterification reaction, and has been widely used in the identification of sugars and glycosylated molecules. As a boric acid derivative, 3-aminophenylboronic acid (APBA) has the advantages of stability, low cost, easy synthesis, etc. Therefore, using APBA as a recognition molecule to prepare magnetic nanomaterials can achieve the enrichment of S. aureus . In order to reduce steric hindrance and ensure the dominant orientation of APBA, thus improving the enrichment performance of target bacteria. The polyethylene glycol (PEG) was used as a mediator to prepare PEG-mediated APBA functionalized magnetic nanomaterials (APBA-PEG-MNs). In addition, this study used FITC-pig IgG to label S. aureus because the Fc fragment of IgG to bind protein A on the surface of S. aureus and realized the detection of S. aureus by detecting fluorescence. Under the optimal experimental conditions, the capture efficiency of APBA-PEG-MNs for S. aureus with the concentration of 2.7 × 10 6 CFU/mL in spinach, juice and pool water spiked samples was 92.6%, 91.6%, 91.6%. The limit of detection of the strategy in spiked samples was 2.7 × 10 2 CFU/mL within 80 min.