Simultaneous Detection of Two Different Bacteria Using QDs and MNPs

The detection of microorganisms has great importance on human life in many fields such as in diagnosis, medicine, pharmacy, food industry etc..[1]. Target bacteria detection is generally done benefiting from plate counting method. However, this is time consuming technique and same procedure should be applied for checking each type of bacteria [2]. In this study, a fast and sensitive sandwich assay has been developed with the combination of immunomagnetic separation (IMS) and fluorescence techniques to enumerate Escherichia coli (E.coli) and Salmonella, simultaneously. Iron oxide core gold shell (Fe3O4@Au) magnetic nanoparticles were prepared and modified with biotinylated antibodies specific to E.coli and Salmonella. Fluorescence labels have been constructed with specific biotinylated antibodies after chitosan coating of CdTe quantum dots (CdTe QDs) and CdTeNi QDs. This novel method is rapid and sensitive for multiplex bacteria detection with a total analysis time less than 60 minutes