A Love wave immunosensor for whole E. coli bacteria detection using an innovative two-step immobilisation approach.
The efficiency of a monomolecular film of (3-glycidoxypropyl) trimethoxysilane (GPTS) on a shear horizontal guided (Love) acoustic wave immunosensor to detect whole Escherichia coli (E. coli) bacteria is demonstrated. Direct anti-E. coli antibodies grafting onto the sensor surface did not lead to a significant bacteria immobilisation, partially attributed to the SiO2 sensor surface roughness. An innovative method has been set up to get around this difficulty and to detect whole bacteria. It consists in grafting goat anti-mouse antibodies (GAM) onto the sensor surface in a first step and introducing E. coli bacteria mixed with anti-E. coli antibodies onto the sensor in a second step. We describe the characteristics of such a technique like sample preparation time (lower than 30 min) and temperature improvements. A 37 degrees C experimental temperature led to the fastest bacteria binding kinetic, reducing the total analysis time. This method enables to keep the specificity of the antibody/antigen interaction and provides significant results in less than 1h. This leads to a detection threshold of 10(6) bacteria/ml in a 500 microl chamber.
Moll
Nicolas
N
Laboratoire IXL, ENSEIRB, CNRS UMR 5818, Université Bordeaux 1, 351 cours de la Libération, F-33405 Talence, France. moll@ixl.fr
Pascal
Emilie
E
Dinh
Duy Haï
DH
Pillot
Jean-Paul
JP
Bennetau
Bernard
B
Rebière
Dominique
D
Moynet
Daniel
D
Mas
Yan
Y
Mossalayi
Djavad
D
Pistré
Jacques
J
Déjous
Corinne
C
D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation*; D004926:Escherichia coli / Q000276:immunology / Q000302:isolation & purification*; D007118:Immunoassay / Q000295:instrumentation; D051379:Mice