Love wave bacterial biosensors and microfluidic network for detection of heavy metal toxicity
Résumé
The presented work deals with the development of a bacteria-based Love wave sensor platform for the detection of heavy metals in liquid medium. The acoustic delay-line was inserted in an oscillation loop and associated with a Polydimethylsiloxane (PDMS) microfluidic network fabricated using soft photolithography and molding. It resulted in a small platform convenient for fast analysis and detection. Whole bacteria (Escherichia. coli) were fixed as bioreceptors onto the acoustic path of the sensor coated with a polyelectrolyte multilayer (PEM) using a simple and efficient layer by layer electrostatic self-assembly procedure. PEM and bacteria deposition were real-time characterized by monitoring the resonance frequency modification due to mass loading effect. Then when a solution of metal ion (Cd2+, Hg2+) was pumped through the microchannels, a significative frequency variation was observed down to 10-12 mol.l-1 concentration, due to changes of bacteria visco-elastic equivalent parameters in presence of toxic heavy metals.