Integrated Love Wave Device Dedicated to Biomolecular Interactions Measurements in Aqueous Media.

Virginie Blondeau-Patissier,Wilfrid Boireau,Gwladys Lengaigne,Gilles Martin,Sylvain Ballandras,William Daniau,Bruno Cavallier

doi:10.3390/s7091992

Abstract

Mass-sensitive electro-acoustic devices such as surface acoustic wave (SAW)micro-balances, capable to operate with aqueous media are particularly favorable for thedevelopment of biosensors. Their dimensions and physical properties offer a large potentialin biological fluid investigations, especially for measuring physical phenomenon (massdeposition, adsorption, pressure...). In this work, we propose a specific gratingconfiguration to lower the influence of viscosity of fluids which reduces the signal dynamicsof the surface wave transducers. A dedicated liquid cell also has been developed to isolatethe electro-active part of the device. The fabrication of the cell is achieved using theSU-8TMphoto-resist, allowing for manufacturing thick structures preventing any contact between thetested liquids and the transducers. Furthermore, the sensing area has been optimized tooptimize the sensor gravimetric sensitivity. The operation of the sensor is illustrated bydetecting bovine serum albumin (BSA) adsorption in the sensing area.

Highlights

Many researches have been initiated to design and manufacture sensors capable to detect and measure the presence of specific molecules in liquids for biological applications
The use of pure shear guided waves in stratified substrates such as amorphous silica on quartz allowing for Love wave excitation appears as an attractive solution to fabricate devices able to operate in water
Pure shear polarized wave based resonators have been successfully implemented for operations using viscous fluid loads

Summary

Introduction

Many researches have been initiated to design and manufacture sensors capable to detect and measure the presence of specific molecules in liquids for biological applications. The use of resonators instead of delay lines is expected to provide better sensing capabilities [5,6,7] when monitoring frequency shifts due to gravimetric effects. Accurate measurements of molecule concentration are expected by monitoring the resonance frequency of two-port synchronous resonators immersed in fluids. This approach did not received too much interest, but we can mention for instance the work by Nomura et al who developed a liquid flow system dedicated to de-ionized water conductivity measurements [8]

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