Integration of Surface Acoustic Wave and Microfluidic Technologies for Liquid-Phase Sensing Applications
Doctoral thesis, 2019

This thesis discusses a new concept for construction of a novel SAW in-liquid sensor employing surface acoustic wave resonance (SAR) in a one-port configuration. In this concept, the reflective gratings of a one-port SAW resonator are employed as mass loading-sensing elements, while the SAW transducer is protected from the measurement environment, reducing power losses significantly.

Microfluidic technologies have developed during the last decades into versatile platforms for miniaturized analytical devices. The devices are small, low cost, capable of multi-step automation resulting in fast turnaround, and allow reducing the amount of reagent and sample consumption, while maintaining a precise control over the environment. In this context, small, cheap and efficient sensors capable of in-liquid operation within microfluidic devices are in a great demand. The introduction of acoustic wave technology onto lab-on-a-chip platforms provides sensing capability that meets these criteria, and allows for an extended set of functions to be implemented, e.g., fast fluidic actuation, contact-free particle manipulation, sorting, and others.

A resonant SAW sensor topology embedded in a polydimethylsiloxane (PDMS) microfluidic analyte delivery system was fabricated and characterized. Designs with the best performance were identified, and initial measurements in a liquid environment are discussed. In comparison to a delay-line topology, the proposed one-port resonant configuration features improved sensitivity, while offering better electrical performance and smaller size, which allows for wafer-scale fabrication and facilitates integration. Following optimization, sensing performance was evaluated by means of different assays, and multiparametric sensing was demonstrated by sharing of sensor components for simultaneous SAR sensing and electrochemical impedance spectroscopy in different frequency bands.

This technological advancement may open pathways to new analytical instrumentation. The small sensor footprint, low energy consumption, and simple two-wire readout facilitate the integration in hand-held “lab on a chip” assay devices, the construction of sensing arrays for parallel sample processing, and the implementation of wireless data transfer schemes.




Impedance Spectroscopy

Surface Acoustic Wave





Kollektorn, MC2, Kemivägen 9, Göteborg
Opponent: Professor Michael Rapp, Karlsruhe Institute of Technology, Germany


Kiryl Kustanovich

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry, Physical Chemistry

Design and characterization of surface acoustic wave resonance (SAR) system for in-liquid sensing

2017 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFC 2017 - Proceedings,; (2017)p. 652-655

Paper in proceedings

A high-performance lab-on-a-chip liquid sensor employing surface acoustic wave resonance

Journal of Micromechanics and Microengineering,; Vol. 27(2017)

Journal article

A high-performance lab-on-a-chip liquid sensor employing surface acoustic wave resonance: part II

Journal of Micromechanics and Microengineering,; Vol. 29(2019)

Journal article

SU-8 free-standing microfluidic probes

Biomicrofluidics,; Vol. 11(2017)

Journal article

Acoustic wave microdevices are based on piezoelectric materials, and have been in commercial use for more than 60 years. The largest user of these devices is the telecommunications industry, where mobile phones and base stations use acoustic wave technology for radio frequency (RF) filtering.  The relationship between acoustic waves and mechanical motion of piezoelectric substrates is nowadays also used in industrial sensing, which includes automotive (e.g. torque and tire pressure sensors), and medical (gas-chemical and biochemical sensors) applications. Acoustic wave sensors are cheap, robust, and very sensitive. The transfer of sensing data is uncomplicated, and can often be achieved passively without external power source, and wirelessly. An acoustic wave sensor detects changes in mass deposited on its surface, and responds to these changes by a shift in resonance frequency. Such devices are essentially highly miniaturized balances with direct electrical readout.
For use in medical diagnostics and treatment, sensors capable of in-liquid operation are important. This thesis describes the development and testing of a new generation of acoustic wave in-liquid sensors, and the integration with a microfluidic sample delivery system.  Microfluidics is a modern means of manipulating tiny volumes of sample solutions in a small device, often for the purpose of processing, and delivering them to the analytical detector. Such integration provides practical advantages, most importantly the ability to mass-produce, parallelize and easily introduce additional functionality within a compact analytical platform.
The new technology described in this thesis is a resonant surface acoustic wave sensor, embedded in a polydimethylsiloxane (PDMS) microfluidic sample delivery system. In this sensor device, mass deposition is not directly measured on the acoustic wave-generating resonator, but indirectly on associated reflector structures, reducing loss of signal, and simplifying signal readout. New sensor layouts were designed, simulated, fabricated, assembled and tested repeatedly, until optimal performance was achieved.

The new acoustic wave technology provides opportunities for the development of very advanced hand-held instruments for high-performance chemical analysis and medical diagnostics, for example to detect pathogenic microorganisms. Thanks to the simplicity and small size of the sensor, such instruments  can be built at low cost, consume very little energy, and can be wirelessly  attached to common devices, such as cellular phones, for data processing.

Reservoir Computing with Real-time Data for future IT (RECORD-IT)

European Commission (Horizon 2020), 2015-09-01 -- 2018-08-31.

Point-of care Influenza Diagnostics FLU-ID

Swedish Foundation for Strategic Research (SSF), 2014-06-01 -- 2019-05-31.

Subject Categories

Medical Laboratory and Measurements Technologies

Manufacturing, Surface and Joining Technology

Nano Technology

Fluid Mechanics and Acoustics

Other Electrical Engineering, Electronic Engineering, Information Engineering



Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4583


Chalmers University of Technology

Kollektorn, MC2, Kemivägen 9, Göteborg

Opponent: Professor Michael Rapp, Karlsruhe Institute of Technology, Germany

More information

Latest update

5/2/2019 3