SH-SAW sensor based microfluidic system for the detection of heavy metal compounds in liquid environments

Abstract

In this work, a guided shear horizontal mode surface acoustic wave (SH-SAW) sensor, fabricated by patterning gold (Au) interdigitated electrodes (IDE) on a 64°YX-LiNbO 3 based piezoelectric substrate, was used for the detection of heavy metal compounds. A flow cell, with a reservoir volume of 3 µl, which employs inlet and outlet valves for the microfluidic chamber and polydimethylsiloxane (PDMS) based microfluidic channels, was also designed and fabricated using an acrylic material. The frequency based response of the SAW sensor towards varying concentrations of heavy metal compounds such as lead nitrate (PbNO 3) and cadmium nitrate (CdNO 3) were investigated. As the surface acoustic wave propagates on the substrate, between input and output IDEs, a shift in the resonant frequency of the SAW device was observed due to the change in velocity of the wave caused by the varying concentrations of the test analytes. The results obtained demonstrated the capability of the system to detect picomolar level concentrations. The response of the SAW sensor is analyzed and presented in this paper.

Surface acoustic wave devices for chemical sensing and microfluidics: a review and perspective

“…83 Since then, the applicability of shear horizontal has been expanded, including oil contamination 34 and heavy metals 84 in ground water. The latter study by Ramshani et al took advantage of modern fabrication techniques to develop a cost efficient and easy-to-use flow cells for heavy metal compound sensing (Fig.…”

Progress of the discovery, application, and control technologies of chemical pesticides in China

“…Unlike the traditional analytical methods, microfluidic chip technology has the advantages of miniaturization, integration, high throughput and low cost, with a lower rate of false positives. Therefore, microfluidic chip technology has a strong application prospect and application value in the fields of rapid detection for food safety (Physics 2013;Scognamiglio et al 2014;Xu 2014), environmental monitoring (Physics 2013;Gammoudi et al 2014;Ramshani et al 2015), and medical diagnosis (El-Ali et al 2006;Yager et al 2006;Sackmann et al 2014). Yang et al (2015) designed a specific microfluidic chip and established an automatic system platform that includes sample mixing, reaction, and detection based on the hydrolysis of organophosphorus pesticides to detect those pesticides in aquatic systems.…”

Surface Acoustic Wave (SAW) for Chemical Sensing Applications of Recognition Layers

“…Nonetheless, these devices have not been extensively studied with microfluidic packages. Integrating SAW with microfluidic [ 150 ] and lab-on-chip (LOC) systems could realize their applications for precise and accurate liquid phase measurements, especially for biosensing [ 151 ]. The combination of SH-SAW and polydimethylsiloxane (PDMS) microfluidic systems for bioanalytes has been reported [ 152 , 153 ].…”