Surface acoustic wave (SAW) sensor for volatile organic compounds (VOCs) detection with calix[4]arene functionalized Gold nanorods (AuNRs) and silver nanocubes (AgNCs)

The detection of chemicals in gas-phase has been employed in a wide variety of applications, including indoor air quality and environmental monitoring, chemical and biochemical processing, and medical diagnostics such as lung cancer screening. In this study, gold nanorod (AuNR) and silver nanocube (AgNC) molecules were functionalized with thiol (Sterminal) containing Calix[4]arene and were investigated for their molecular recognition properties on surface acoustic wave (SAW) transducer device surfaces. These novel sensing materials on transducer SAW device were investigated for the detection of polar (acetone, ethanol, chloroform, and humidity) and nonpolar (n-hexane, toluene, isoprene) volatile organic compounds (VOCs), among which are key markers for disease diagnosis, such as toluene present in exhaled breath of lung cancer patients. Sensor responses were discussed under various concentration levels in terms of selectivity, sensitivity, limit of detection, and response time. After AuNR and AgNC modification with Calix[4]arene, sensitivity of sensors has reached up to six to eightfold higher than the individual responses, with a selectivity towards chloroform and toluene, respectively.