Staphylococcus aureus(S.aureus)has been identified as one of the major foodborne pathogenic bacteria.The development of rapid detection methods for S.aureus is needed for assuring food safety.In this study,quantum dot...Staphylococcus aureus(S.aureus)has been identified as one of the major foodborne pathogenic bacteria.The development of rapid detection methods for S.aureus is needed for assuring food safety.In this study,quantum dots were used as fluorescent labels in an immunoassay for quantitative detection of S.aureus.Firstly,biotin-labeled anti-S.aureus antibody was conjugated with streptavidin-coated magnetic nanobeads(180 nm diameter)and used to separate S.aureus cells.Then streptavidin coated quantum dots(QDs)were conjugated with biotin-labeled anti-S.aureus antibody and used as the fluorescence labels to mix with the separated S.aureus.Finally the fluorescence intensity of the bead-cell-QD complexes was measured at a wavelength of 620 nm.A linear relationship between S.aureus cell number(X)and fluorescence intensity(Y)was found for cell numbers ranging from 10^(3) to 10^(6) CFU(Colony Forming Unit)/mL,and the detection limit was 10^(3) CFU/mL.The regression model can be expressed as Y=7.68X+35.06 with R^(2)=0.94.The detection of S.aureus in food sample was explored initially.The fluorescence intensity of food sample was close to the background,so it was not satisfied.Further study will focus on the application of the method for detection of S.aureus in food sample.展开更多
基金This research was financially supported by the Fundamental Research Funds for the Central Universities of China(No.QN2011144)the Yangling Modern Agriculture International Institute(No.A213021005).
文摘Staphylococcus aureus(S.aureus)has been identified as one of the major foodborne pathogenic bacteria.The development of rapid detection methods for S.aureus is needed for assuring food safety.In this study,quantum dots were used as fluorescent labels in an immunoassay for quantitative detection of S.aureus.Firstly,biotin-labeled anti-S.aureus antibody was conjugated with streptavidin-coated magnetic nanobeads(180 nm diameter)and used to separate S.aureus cells.Then streptavidin coated quantum dots(QDs)were conjugated with biotin-labeled anti-S.aureus antibody and used as the fluorescence labels to mix with the separated S.aureus.Finally the fluorescence intensity of the bead-cell-QD complexes was measured at a wavelength of 620 nm.A linear relationship between S.aureus cell number(X)and fluorescence intensity(Y)was found for cell numbers ranging from 10^(3) to 10^(6) CFU(Colony Forming Unit)/mL,and the detection limit was 10^(3) CFU/mL.The regression model can be expressed as Y=7.68X+35.06 with R^(2)=0.94.The detection of S.aureus in food sample was explored initially.The fluorescence intensity of food sample was close to the background,so it was not satisfied.Further study will focus on the application of the method for detection of S.aureus in food sample.
