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Single Interdigital Transducer Approach for Gravimetrical SAW Sensor Applications in Liquid Environments.

Authors :
Nguyen VH
Kaulen C
Simon U
Schnakenberg U
Source :
Sensors (Basel, Switzerland) [Sensors (Basel)] 2017 Dec 17; Vol. 17 (12). Date of Electronic Publication: 2017 Dec 17.
Publication Year :
2017

Abstract

Surface acoustic wave (SAW) devices are well known for mass-sensitive sensor applications. In biosensing applications, chemical and biochemically evoked binding processes on surfaces are detected in liquid environments using delay line or resonator sensor configurations, preferably in combination with the appropriate microfluidic devices. All configurations share the common feature of analyzing the transmission characteristic of the propagating SAW. In this paper, a novel SAW-based impedance sensor type is introduced which uses only one interdigital transducer (IDT), simultaneously as the SAW generator and the sensor element. Here, the input port reflection coefficient S <subscript>11</subscript> is measured at the IDT instead of the commonly used S <subscript>21</subscript> transmission forward gain parameter. Thus, a sharp and distinct peak of the S <subscript>11</subscript> spectrum is obtained, enabling a comfortable direct readout of the sensor signal. Proof of the concept was gained by analyzing the specific binding of the 4-mercaptophenylacetic acid gold nanoparticles (MPA-AuNP) directly to the IDT surface. The corresponding binding kinetic of the MPA-AuNP on the functionalized gold surface has been analyzed and a sensitivity of 7.4 mΩ nM <superscript>-1</superscript> has been determined.<br />Competing Interests: The authors declare no conflicts of interest.

Details

Language :
English
ISSN :
1424-8220
Volume :
17
Issue :
12
Database :
MEDLINE
Journal :
Sensors (Basel, Switzerland)
Publication Type :
Academic Journal
Accession number :
29258213
Full Text :
https://doi.org/10.3390/s17122931