The Research For Rapid Detection Of Staphylococcus Aureus In Food Based On The Colorimetric Method

Staphylococcus aureus（S.aureus）as a kind of widelydistributed pathogenic bacteria has being brought great threat to human health,so sensitive and selective detection of S.aureus is of great significance.A simple,sensitive,and selective colorimetric method for the detection of S.aureus was developed by combining nanomaterial-catalyzed chromogenic reaction and aptamer recognition.The main contents are as follows:（1）Copper-based metal-organic framework（Cu-MOF）nanoparticles with an average diameter of 550 nm were synthesized from2-aminoterephthalic acid and copper nitrate by a mixed solvothermal method.The Cu-MOF nanoparticles are shown to possess peroxidase-like activity that can catalyze 3,3,5,5-tetramethylbenzidine（TMB）to produce a yellow chromogenic reaction in the presence of H₂O₂.Based on the chromogenic reaction,a simple,cheap,and highly sensitive and selective colorimetric method for the detection of H₂O₂ and glucose has been developed.（2）With the increase of Cu-MOF concentration,the yellow color of the TMB-H₂O₂ solutions gradually deepens,which inspires us to develop a new colorimetric strategy for the detection of S.aureus based on the concentration change of Cu-MOF nanoparticles.By combining Cu-MOF-catalyzed chromogenic reaction with aptamer recognition and magnetic separation,a simple,rapid,sensitive,and selective colorimetric method for the detection of S.aureus was developed.The linear range for S.aureus detection is from 50 to 10000 CFU mL^-1with a detection limit of 20 CFU mL^-1.The application potential of the proposed method was also studied by detecting S.aureus in milks..（3）In this work,bimetallic copper-gold nanoparticles（Cu-Au NPs）with special response to iodide ions were synthesized.Cu-Au NPs can chemically absorb iodide ions,and iodide ions can catalyze TMB to produce a chromogenic reaction,so the iodide ion-catalyzed chromogenic reaction can be regulated by Cu-Au NPs.By further utilizing the special recognition of aptamer-modified Cu-Au NPs to S.aureus,a simple,rapid,sensitive,and selective colorimetric method for the detection of S.aureus was developed.