scholarly journals Microwave Spoof Surface Plasmon Polariton-Based Sensor for Ultrasensitive Detection of Liquid Analyte Dielectric Constant

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5477
Author(s):  
Ivana Podunavac ◽  
Vasa Radonic ◽  
Vesna Bengin ◽  
Nikolina Jankovic

In this paper, a microwave microfluidic sensor based on spoof surface plasmon polaritons (SSPPs) was proposed for ultrasensitive detection of dielectric constant. A novel unit cell for the SSPP structure is proposed and its behaviour and sensing potential analysed in detail. Based on the proposed cell, the SSPP microwave structure with a microfluidic reservoir is designed as a multilayer configuration to serve as a sensing platform for liquid analytes. The sensor is realized using a combination of rapid, cost-effective technologies of xurography, laser micromachining, and cold lamination bonding, and its potential is validated in the experiments with edible oil samples. The results demonstrate high sensitivity (850 MHz/epsilon unit) and excellent linearity (R2 = 0.9802) of the sensor, which, together with its low-cost and simple fabrication, make the proposed sensor an excellent candidate for the detection of small changes in the dielectric constant of edible oils and other liquid analytes.

2014 ◽  
Vol 625 ◽  
pp. 316-321
Author(s):  
Miyu Ozaki ◽  
Tomohisa Sakai ◽  
Hiromichi Murata ◽  
Ryoshu Furutani

When optical waves make the free electrons on a metal surface resonate, optical energy propagates along the surface as density waves of the free electrons. The longitudinal waves and electrical fields of the electrons are called surface plasmon polaritons (SPPs), which are widely applied in high sensitivity sensors because the excitation of SPPs sensitively depends on the refractive index of the surrounding dielectric sample. Here, we report the identification of fluids by using the color dispersion of SPPs. Silver film on a prism surface is illuminated with white light to excite SPPs. A color component in the white light is thereby selectively coupled with SPPs due to the color dispersion that depends on the refractive index of the fluid on the film. Thus, theoretically, when the refractive index is changed, the color of SPPs changes as well. Our application uses a medium consisting of fluid samples to be identified. The proposed identification method can be applied to fluid analysis for label-free visualization of or as a simple analysis method, since the refractive indices or concentrations of the sample fluids directly affect the color of the SPPs, and this color can be visually identified. We theoretically confirmed that the color of SPPs excited with white light illumination can help to differentiate between water and ethanol. Experimentally, SPPs belonging to the frequency region of the color green were detected when the sample was water, and the color changed to red when ethanol was used instead. In the future, we plan to develop simple, small, sensitive, and low-cost sensors that can determine the concentration and refractive index of fluids on the basis of the color of the SPPs.


2012 ◽  
Vol 1399 ◽  
Author(s):  
Kajal Jindal ◽  
Monika Tomar ◽  
Vinay Gupta

ABSTRACTTemperature dependent optical properties of RF-sputtered c-axis oriented ZnO:N thin film have been investigated. Surface Plasmon modes are excited at the metal-dielectric interface in the Kretschmann-Reather configuration using prism coupling technique. Effect of ZnO:N thin film deposited over Prism-Au structure on the SPR reflectance is studied over a wide range of temperature from 300–500 K at 633 nm wavelength. The value of dielectric constant of ZnO:N film obtained by fitting the experimentally obtained data with the theoretically generated SPR curve at the optical frequency is found to increase linearly with temperature. The increase in dielectric constant (4.03 to 4.11) with increase in temperature from 300 K to 500 K indicates a promising application of the system as an efficient low-cost temperature sensor.


Author(s):  
Alireza Shahsafi ◽  
Jad Salman ◽  
Bryan E. Rubio Perez ◽  
Yuzhe Xiao ◽  
Chenghao Wan ◽  
...  

2021 ◽  
Author(s):  
Pattamaporn Kittayapong ◽  
Parinda Thayanukul ◽  
Benchaporn Lertanantawong ◽  
Worachart Sirawaraporn ◽  
Surat Charasmongkolcharoen ◽  
...  

Background Wolbachia is an endosymbiont bacterium generally found in about 40% of insects, including mosquitoes, but it is absent in Aedes aegypti which is an important vector of several arboviral diseasesdengue, chikungunya, Zika, and yellow fever. The evidence that Wolbachia trans-infected Ae. aegypti mosquitoes lost their vectorial competence and became less capable of transmitting arboviruses to human hosts highlights the potential of using Wolbachia - based approaches for prevention and control of arboviral diseases. Recently, release of Wolbachia trans-infected Ae. aegypti has been deployed widely in many countries for the control of mosquito-borne viral diseases. Field surveillance and monitoring of Wolbachia presence in released mosquitoes is important for the success of these control programs. So far, a number of studies have reported the development of loop mediated isothermal amplification (LAMP) assays to detect Wolbachia in mosquitoes, but the methods still have some specificity issues. Methodology/Principal Findings We describe here the development of a LAMP combined with the DNA strand displacement-based electrochemical sensor (BIOSENSOR) method to detect wAlbB Wolbachia in trans-infected Ae . aegypti . Our developed LAMP primers were more specific to wAlbB detection than those of the previous published ones if  the assays were conducted with low-cost and non-specific detecting dyes. The detection capacity of our LAMP technique was 3.8 nM and the detection limit reduced to 2.16 fM when combined with the BIOSENSOR. Our study demonstrates that the BIOSENSOR can also be applied as a stand-alone method for detecting Wolbachia ; and it showed high sensitivity when used with the crude DNA extracts of macerated mosquito samples without DNA purification. Conclusions/Significance Our results suggest that both LAMP and BIOSENSOR, either used in combination or stand-alone, are robust and sensitive. The methods have good potential for routine detection of Wolbachia in mosquitoes during field surveillance and monitoring of Wolbachia -based release programs, especially in countries with limited resources.


2021 ◽  
Vol 10 (2) ◽  
pp. 163-169
Author(s):  
Ravinder Gaur ◽  
Himanshu Mohan Padhy ◽  
Manikandan Elayaperumal

Abstract. In this short communication, we propose a surface plasmon resonance (SPR) sensor based on a ZnO / Au hybrid thin-film material structure and experimentally investigate its sensitivity improvement. The Kretschmann-based SPR sensor utilizes ZnO thin films and nanostructures for performance enhancement. The advancement in SPR technology relies on a low-cost, high-sensitivity, and high-selectivity sensor. Metal oxide (MO) has been incorporated into the SPR sensor to be used for detection of biological and chemical compounds. ZnO as one of the metal oxides is an attractive material due to its unique physical and optical properties. Numerous techniques for fabrication and characterization of ZnO on SPR gold substrate have been studied. The mechanism for gas and biomolecule detection depends on their interaction with the ZnO surface, which is mainly attributed to the high isoelectric point of ZnO. There are several types of ZnO nanostructures which have been employed for SPR application based on the Kretschmann configuration. In the future, the thin film and nanostructures of ZnO could be a potential application for miniature design, robust, high sensitivity, and a low-cost portable type of SPR biosensor to be used for on-site testing in a real-time and label-free manner. The present work includes the application of a developed SPR setup for gas sensing at room temperature using a specially designed gas cell. The change in the optical properties of dielectric layers (ZnO) with adsorption of gases (NO2) in order to develop an optical sensor has been presented. The obtained results emphasize the applications of an SPR setup for the study of interaction of adsorbed gas molecules, with dielectrics and gas sensing.


Chemosensors ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 57 ◽  
Author(s):  
Andrew Donohoe ◽  
Gareth Lacour ◽  
Peter McCluskey ◽  
Dermot Diamond ◽  
Margaret McCaul

A sensing platform for the in situ, real-time analysis of phosphate in natural waters has been realised using a combination of microfluidics, colorimetric reagent chemistries, low-cost LED-based optical detection and wireless communications. Prior to field deployment, the platform was tested over a period of 55 days in the laboratory during which a total of 2682 autonomous measurements were performed (854 each of sample, high standard and baseline, and 40 × 3 spiked solution measurements). The platform was subsequently field-deployed in a freshwater stream at Lough Rea, Co., Galway, Ireland, to track changes in phosphate over a five day period. During this deployment, 165 autonomous measurements (55 each of sample, high standard, and baseline) were performed and transmitted via general packet radio service (GPRS) to a web interface for remote access. Increases in phosphate levels at the sampling location coincident with rainfall events (min 1.45 µM to max 10.24 µM) were detected during the deployment. The response was found to be linear up to 50 µM PO43−, with a lower limit of detection (LOD) of 0.09 µM. Laboratory and field data suggest that despite the complexity of reagent-based analysers, they are reasonably reliable in remote operation, and offer the best opportunity to provide enhanced in situ chemical sensing capabilities. Modifications that could further improve the reliability and scalability of these platforms while simultaneously reducing the unit cost are discussed.


2010 ◽  
Vol 139-141 ◽  
pp. 1554-1557 ◽  
Author(s):  
Xi Xi Huang ◽  
Zhong Cao ◽  
Yong Le Liu ◽  
Yi Min Dai ◽  
Ju Lan Zeng ◽  
...  

An novel optical nano biosensor based on gold capped nano-particles for detecting binding events between ligands and receptor molecules as well as interactions among proteins without use of labels has been presented in this paper. The optical properties of nano-sized gold particles exhibiting pronounced adsorption in the visible region which called as localized surface plasmon resonance (LSPR) have been exploited, whose peak wavelengths depended exquisitely on the refractive index of the surrounding. In comparison with surface plasmon resonance (SPR) technology, the optical nano biosensor possessed high sensitivity, surprisingly low “bulk effect”, ease of preparation, and low-cost polymer based fabrication, which opened a promising bioanalytical application in practice.


Nanoscale ◽  
2020 ◽  
Vol 12 (19) ◽  
pp. 10809-10815 ◽  
Author(s):  
Zhongwen Long ◽  
Yuzhang Liang ◽  
Lei Feng ◽  
Hui Zhang ◽  
Mingze Liu ◽  
...  

A low-cost, large scale plasmonic metasurface sensing platform shows enormous potential for highly sensitive and selective SERS-based glucose detection.


2014 ◽  
Vol 16 (28) ◽  
pp. 14706-14712 ◽  
Author(s):  
Xuan He ◽  
Hui Wang ◽  
Zhongbo Li ◽  
Dong Chen ◽  
Qi Zhang

Low-cost SERS sensors were fabricated by 4-ATP-functionalized ZnO–Ag hybrid substrates for TNT detection with high sensitivity, selectivity and reproducibility.


2019 ◽  
Author(s):  
Zachary Ballard ◽  
Hyou-Arm Joung ◽  
Artem Goncharov ◽  
Jesse Liang ◽  
Karina Nugroho ◽  
...  

ABSTRACTWe present a deep learning-based framework to design and quantify point-of-care sensors. As its proof-of-concept and use-case, we demonstrated a low-cost and rapid paper-based vertical flow assay (VFA) for high sensitivity C-Reactive Protein (hsCRP) testing, a common medical test used for quantifying the degree of inflammation in patients at risk of cardio-vascular disease (CVD). A machine learning-based sensor design framework was developed for two key tasks: (1) to determine an optimal configuration of immunoreaction spots and conditions, spatially-multiplexed on a paper-based sensing membrane, and (2) to accurately infer the target analyte concentration based on the signals of the optimal VFA configuration. Using a custom-designed mobile-phone based VFA reader, a clinical study was performed with 85 human serum samples to characterize the quantification accuracy around the clinically defined cutoffs for CVD risk stratification. Results from blindly-tested VFAs indicate a competitive coefficient of variation of 11.2% with a linearity of R2 = 0.95; in addition to the success in the high-sensitivity CRP range (i.e., 0-10 mg/L), our results further demonstrate a mitigation of the hook-effect at higher CRP concentrations due to the incorporation of antigen capture spots within the multiplexed sensing membrane of the VFA. This paper-based computational VFA that is powered by deep learning could expand access to CVD health screening, and the presented machine learning-enabled sensing framework can be broadly used to design cost-effective and mobile sensors for various point-of-care diagnostics applications.


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