RESUMO
Escherichia coli O157:H7 is detected using a remote-query (wireless, passive) magnetoelastic sensor platform to which a 1 microm thick layer of Bayhydrol 110 and then a layer of functionalized mannose is applied. The multivalent binding of lectin concanavalin A (Con A) to the E. coli surface O-antigen and mannose favors the strong adhesion of E. coli to the mannose-modified magnetoelastic sensor; E. coli is rigidly and strongly attached on the mannose-modified sensor through Con A, which works as a bridge to bind E. coli to the mannose-modified sensor surface. As E. coli is bound to the sensor, its resonance frequency shifts, enabling quantification of E. coli concentration with a limit of detection of 60 cells/mL and a linear logarithmic response range of 6.0 x 10(1) to 6.1 x 10(9) cells/mL. The analysis can be directly conducted without incubation and completed in 3 h or less.
Assuntos
Técnicas Biossensoriais/métodos , Concanavalina A/metabolismo , Escherichia coli O157/isolamento & purificação , Escherichia coli O157/metabolismo , Adsorção , Assepsia , Cálcio/metabolismo , Escherichia coli O157/química , Magnetismo , Manganês/metabolismo , Manose/metabolismo , Antígenos O/metabolismo , Especificidade por Substrato , Fatores de TempoRESUMO
Described is application of the remote-query (wireless, passive) magnetoelastic sensor platform for direct detection and monitoring of bacterium contamination of milk within hermetically sealed containers. Specific application is made to the quantification of Staphylococcus aureus ssp. anaerobius (S. aureus) concentrations in milk. S. aureus growth changes milk viscosity, in turn changing the resonance frequency of the liquid immersed sensor allowing S. aureus concentrations of 10(3) to 10(7)cellsml(-1) to be directly quantified.