Paper
16 August 2004 An SU-8 liquid cell for surface acoustic wave biosensors
Laurent Alain Francis, Jean-Michel Friedt, Carmen Bartic, Andrew Campitelli
Author Affiliations +
Abstract
One significant challenge facing biosensor development is packaging. For surface acoustic wave based biosensors, packaging influences the general sensing performance. The acoustic wave is generated and received thanks to interdigital transducers and the separation between the transducers defines the sensing area. Liquids used in biosensing experiments lead to an attenuation of the acoustic signal while in contact with the transducers. We have developed a liquid cell based on photodefinable epoxy SU-8 that prevents the presence of liquid on the transducers, has a small disturbance effect on the propagation of the acoustic wave, does not interfere with the biochemical sensing event, and leads to an integrated sensor system with reproducible properties. The liquid cell is achieved in two steps. In a first step, the SU-8 is precisely patterned around the transducers to define 120 μm thick walls. In a second step and after the dicing of the sensors, a glass capping is placed manually and glued on top of the SU-8 walls. This design approach is an improvement compared to the more classical solution consisting of a pre-molded cell that must be pressed against the device in order to avoid leaks, with negative consequences on the reproducibility of the experimental results. We demonstrate the effectiveness of our approach by protein adsorption monitoring. The packaging materials do not interfere with the biomolecules and have a high chemical resistance. For future developments, wafer level bonding of the quartz capping onto the SU-8 walls is envisioned.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Laurent Alain Francis, Jean-Michel Friedt, Carmen Bartic, and Andrew Campitelli "An SU-8 liquid cell for surface acoustic wave biosensors", Proc. SPIE 5455, MEMS, MOEMS, and Micromachining, (16 August 2004); https://doi.org/10.1117/12.544779
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CITATIONS
Cited by 19 scholarly publications.
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KEYWORDS
Liquids

Acoustics

Transducers

Biosensors

Sensors

Packaging

Epoxies

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