Love Acoustic Wave Research Articles

PDMS (Polydimethylsiloxane) Microfluidic Chip Molding for Love Wave Biosensor

We present the development of new Polydimethylsiloxane (PDMS) chips, which are coupled with Love acoustic wave sensors to realize a detection cell of bio-organisms in liquid media. Three generations of biocompatible PDMS chips have been developed. Built-in thermistors allow a thermal control (±0.05°C). Unlike the usual assemblies, this chip is maintained by pressure on the sensor and not sticked on its surface. This technique makes it entirely removable and cleanable. Therefore, the surface of the sensor can be functionalized or regenerated. The realization of these chips is quick and inexpensive.We here outline the development of these different cells and present characteristics of the resulting microsensors, depending on the chip configuration. Real-time responses during antibodies immobilization are presented and analyzed. Antibodies at typical concentration of 45μg/ml are successfully fast detected, with response times from 350s for static down to 90s for dynamic detection setup, with similar sensitivity. Discussions on the mechanical fluid behaviour at the near sensor surface allow to better understand these results and to investigate further developments aiming at improving the quality of the fluid stream in order to even increase future sensor characteristics.

PDMS (Polydimethylsiloxane) Microfluidic Chip Molding for Love Wave Biosensor

We present the development of new Polydimethylsiloxane (PDMS) chips, which are coupled with Love acoustic wave sensors to realize a detection cell of bio-organisms in liquid media. Three generations of biocompatible PDMS chips have been developed. Built-in thermistors allow a thermal control ({plus minus}0.05{degree sign}C). Unlike the usual assemblies, this chip is maintained by pressure on the sensor and not bonded welded on its surface. This technique makes it entirely removable and cleanable. Therefore, the surface of the sensor can be functionalised or regenerated. The realization of these chips is quick and inexpensive.

Poly(dimethylsiloxane)-Coated Sensor Devices for the Formation of Supported Lipid Bilayers and the Subsequent Study of Membrane Interactions

The development of smooth hydrophilic surfaces that act as substrates for supported lipid bilayers (SLBs) is important for membrane studies in biology and biotechnology. In this article, it is shown that thin films of poly(dimethylsiloxane) (PDMS) formed on a sensor surface can be used as a substrate for the deposition of reproducible and homogeneous zwitterionic SLBs by the direct fusion of vesicles. Poly(dimethylsiloxane) solution (1% w/v) was spin coated on Love acoustic wave and surface plasmon resonance devices to form a thin PDMS layer. Acoustic, fluorescence, and contact angle measurements were used for the optimization of the PDMS film properties as a function of plasma etching time; parameters of interest involve the thickness and hydrophilicity of the film and the ability to induce the formation of homogeneous SLBs without adsorbed vesicles. The application of PDMS-coated sensor devices to the study membrane of interactions was demonstrated during the acoustic and fluorescence detection of the binding of melittin and defensin Crp4 peptides to model supported lipid bilayers.

Multipurpose Love acoustic wave immunosensor for bacteria, virus or proteins detection

A multipurpose Love acoustic wave biosensor is described in this article. As mass loading is one of the main effect involved in acoustic wave sensors, a great range of biomolecules could be detected using such sensors. In this way, the antibody/antigen binding property was used to immobilise the target species. We first compared different coupling agents to link the antibodies sensitive layer to the SiO 2 sensor surface. Results showed that GPTS monolayer, allowing covalent attachment of antibodies bioreceptors, is better suited than DTSP and protein G. It permits to obtain a dense, stable and reproducible sensitive layer of antibodies. Then, different biological species with different size and shape like proteins, bacteriophages or bacteria were detected using such sensor. Different models have been chosen to validate the effective detection of a large species range: an anti-mouse antibody has been used to simulate small molecules (< 10 nm) like proteins or toxins, bacteriophage M13 for species lower than 1 μm like virus, and Escherichia coli for bacteria which are typically longer than 1 μm. Each kind of species were successfully quickly detected from few seconds for small proteins to one hour for bacteria, with detection threshold down to 4 ng/mm 2 for protein and 10 6 cfu per milliliter for bacteria.