Fast-response surface acoustic wave humidity sensor based on hematoporphyrin film

A respiratory monitoring system based on a quartz crystal microbalance (QCM) sensor with a functional film was designed and investigated. Porphyrins 5,10,15,20-tetrakis-(4-sulfophenyl)-21H,23H-porphine (TSPP) and 5,10,15,20-tetrakis-(4-sulfophenyl)-21H, 23H-porphine manganese (III) chloride (MnTSPP) used as sensitive elements were assembled with a poly(diallyldimethyl ammonium chloride) (PDDA). Films were deposited on the QCM resonators using layer-by-layer method in order to develop the sensor. The developed system, in which the sensor response reflects lung movements, was able to track human respiration providing respiratory rate (RR) and respiratory pattern (RP). The sensor system was tested on healthy volunteers to compare RPs and calculate RRs. The operation principle of the proposed system is based on the fast adsorption/desorption behavior of water originated from human breath into the sensor films deposited on the QCM electrode.

Section: Introductionmentioning

confidence: 70%

Respiratory Monitoring by Porphyrin Modified Quartz Crystal Microbalance Sensors

Selyanchyn

Korposh

Wakamatsu

et al. 2011

“…Various SAW sensors had been developed and applied to physical, chemical, industrial and biomedical fields [1,2,3,4,5]. Meanwhile, to fabricate SAW sensors with high sensitivity and low temperature coefficients, multilayered structures were generally selected, in which ZnO films deposited on substrates were preferred layered materials [3,4,6,7].…”

Section: Introductionmentioning

confidence: 99%

Simulation of SAW Humidity Sensors Based on ( 11 2 ¯ 0 ) ZnO/R-Sapphire Structures

Lan

Zhang

Fan

et al. 2016

The characteristics of two types of surface acoustic waves SAWs (Rayleigh waves and Love waves) propagating in bilayered structures of (112¯0)ZnO/R-sapphire are simulated by a finite element method (FEM) model, in which both SAWs have crossed propagation directions. Furthermore, based on the bilayered structures, the frequency responses of Rayleigh wave and Love wave humidity sensors are also simulated. Meanwhile, the frequency shifts, insertion loss changes and then the sensitivities of both humidity sensors induced by the adsorbed water layer perturbations, including the mechanical and electrical factors, are calculated numerically. Generally, the characteristics and performances of both sensors are strongly dependent on the thickness of the ZnO films. By appropriate selecting the ratio of the film thickness to SAW wavelength for each kind of the sensors, the performances of both sensors can be optimized.

“…[ 1 ]. Due to their high sensitivity to the surface mass loading phenomenon, recently a growing number of surface acoustic waves (SAWs) techniques [ 2 , 3 , 4 , 5 ] have been employed for various sensor applications, wherein SAW humidity sensors have attracted much attention. A Love wave is a kind of layered SAW with particle displacement only in the shear horizontal (SH) direction.…”

Section: Introductionmentioning

confidence: 99%

The Development of Love Wave-Based Humidity Sensors Incorporating Multiple Layers

Wang

Liu

2015

A Love wave humidity sensor is developed by using a multilayer structure consisting of PVA/SiO2 layers on an ST-90°X quartz substrate. The theoretical result shows that the sensor with such a two-layer structure can achieve a higher sensitivity and a smaller loss than the structures with a single polymer layer. Comparative experiments are performed for the sensor incorporating PVA/SiO2 layers and the sensor incorporating a PVA layer. The experimental results agree well with the theoretical predication.