Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Sep 8;19(18):3876.
doi: 10.3390/s19183876.

Design of a Portable Orthogonal Surface Acoustic Wave Sensor System for Simultaneous Sensing and Removal of Nonspecifically Bound Proteins

Affiliations
Free PMC article

Design of a Portable Orthogonal Surface Acoustic Wave Sensor System for Simultaneous Sensing and Removal of Nonspecifically Bound Proteins

Shuangming Li et al. Sensors (Basel). .
Free PMC article

Abstract

One challenge for current surface acoustic wave (SAW) biosensors is reducing nonspecific adsorption. A device propagating Rayleigh and shear horizontal surface acoustic waves in orthogonal directions fabricated in ST quartz has the capability of achieving simultaneous detection and nonspecific binding (NSB) protein removal. Current measurement methods for a SAW sensor system based on this device require large-size and expensive equipment such as a vector network analyzer (VNA), signal generator, and frequency counter, which are not suitable for portable, especially point-of-care, applications. In this work, a portable platform based on a direct digital synthesizer (DDS) is investigated for the orthogonal SAW sensor, integrating signal synthesis, gain control, phase/amplitude measurement, and data processing in a small, portable electronic system. This prototype was verified for both stability and repeatability, and the results matched very well with VNA measurements. Finally, system performance in real-time sensing and NSB removal was evaluated.

Keywords: biosensing; direct digital synthesis; non-specific binding; portable sensor; protein fouling; quartz; surface acoustic wave.

Conflict of interest statement

A provisional patent application has been made by the University of South Florida.

Figures

Figure 1
Figure 1
(a) Schematic diagram of NSB protein removal using acoustic streaming forces generated by the Rayleigh wave device; (b) different wave modes in the orthogonal device in ST quartz; (c) photograph of an orthogonal surface acoustic wave (SAW) chip.
Figure 2
Figure 2
Schematic of two commonly methods for SAW device measurement: (a) Frequency detection of the SAW oscillator; (b) phase detection of SAW with a signal generator and a phase detector [21,27].
Figure 3
Figure 3
(a) Portable system circuit boards; (b) 3D printed packaging.
Figure 4
Figure 4
Schematic of direct digital synthesizer (DDS) based orthogonal SAW system electronics.
Figure 5
Figure 5
Schematic of SAW sensing and nonspecific binding (NSB) removal strategy.
Figure 6
Figure 6
(a,b) Oscilloscope measurement results at 100 MHz and 400 MHz, with digital gain amplifier’s power attenuation coefficient of 15 dB; (c) Output voltage in different frequencies vs. power attenuation coefficient of digital gain amplifier.
Figure 7
Figure 7
Circuit stability test at different frequencies: (a) amplitude; (b) phase angle.
Figure 8
Figure 8
Comparison of amplitude vs. frequency results with vector network analyzer (VNA) measurement: (a,b) Sensing path and (c,d) removal path; left for portable prototype and right for VNA. The series 1–3 are triplicate measurement results of the orthogonal SAW device.
Figure 8
Figure 8
Comparison of amplitude vs. frequency results with vector network analyzer (VNA) measurement: (a,b) Sensing path and (c,d) removal path; left for portable prototype and right for VNA. The series 1–3 are triplicate measurement results of the orthogonal SAW device.
Figure 9
Figure 9
Phase response of the SAW device to water drop loading and drawing.
Figure 10
Figure 10
Phase response of the SAW device to the removal power switching on/off.
Figure 11
Figure 11
Phase response of the SAW device to mouse anti-rabbit IgG binding. Note that the relative phase shift is compared to the PBS solution baseline.
Figure 12
Figure 12
Phase response of the SAW device to (a) bovine serum albumin (BSA) non-specifically binding on the surface and (b) RF power on/off for NSB removal.

Similar articles

See all similar articles

References

    1. Länge K., Rapp B.E., Rapp M. Surface acoustic wave biosensors: A review. Anal. Bioanal. Chem. 2008;391:1509–1519. doi: 10.1007/s00216-008-1911-5. - DOI - PubMed
    1. Gronewold T.M.A. Surface acoustic wave sensors in the bioanalytical field: Recent trends and challenges. Anal. Chim. Acta. 2007;603:119–128. doi: 10.1016/j.aca.2007.09.056. - DOI - PubMed
    1. Andle J.C., Vetelino J.F. Acoustic wave biosensors. Sens. Actuators A Phys. 1994;44:167–176. doi: 10.1016/0924-4247(94)00801-9. - DOI
    1. Ballantine D.S., Jr., White R.M., Martin S.J., Ricco A.J., Zellers E.T., Frye G.C., Wohltjen H. Acoustic Wave Sensors: Theory, Design and Physico-chemical Applications. Elsevier; Amsterdam, The Netherlands: Oct 21, 1996.
    1. Kovacs G., Venema A. Theoretical comparison of sensitivities of acoustic shear wave modes for (bio) chemical sensing in liquids. Appl. Phys. Lett. 1992;61:639–641. doi: 10.1063/1.107807. - DOI
Feedback