High Fundamental Frequency (HFF) Monolithic Resonator Arrays for Biosensing Applications: Design, Simulations, Experimental, Characterization

© 2020 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] Miniaturized, high-throughput, cost-effective sensing devices are needed to advance lab-on-a-chip technologies for healthcare, security, environmental monitoring, food safety, and research applications. Quartz crystal microbalance with dissipation (QCMD) is a promising technology for the design of such sensing devices, but its applications have been limited, until now, by low throughput and significant costs. In this work, we present the design and characterization of 24-element monolithic QCMD arrays for high-throughput and low-volume sensing applications in liquid. Physical properties such as geometry and roughness, and electrical properties such as resonance frequency, quality factor, spurious mode suppression, and interactions between array elements (crosstalk), are investigated in detail. In particular, we show that the scattering parameter, S 21 , commonly measured experimentally to investigate crosstalk, contains contributions from the parasitic grounding effects associated with the acquisition circuitry. Finite element method simulations do not take grounding effects into account explicitly. However, these effects can be effectively modelled with appropriate equivalent circuit models, providing clear physical interpretation of the different contributions. We show that our array design avoids unwanted interactions between elements and discuss in detail aspects of measuring these interactions that are often-overlooked.The authors would also like to thank Jorge Martínez from the Laboratory of High Frequency Circuits (LCAF) of the Universitat Politècnica de València (UPV) for assistance with profilometry, and Manuel Planes, José Luis Moya, Mercedes Tabernero, Alicia Nuez, and Joaquin Fayos from the Electron Microscopy Services of the UPV for helping with the AFM, and SEM measurements. M. Calero is the recipient of the doctoral fellowship BES-2017-080246 from the Spanish Ministry of Economy, Industry and Competitiveness, Madrid, Spain.Fernández Díaz, R.; Calero-Alcarria, MDS.; Reviakine, I.; García, JV.; Rocha-Gaso, MI.; Arnau Vives, A.; Jiménez Jiménez, Y. (2021). High Fundamental Frequency (HFF) Monolithic Resonator Arrays for Biosensing Applications: Design, Simulations, Experimental, Characterization. IEEE Sensors Journal. 21(1):284-295. https://doi.org/10.1109/JSEN.2020.3015011S28429521

Micro-Resonators: The Quest for Superior Performance

Microelectromechanical resonators are no longer solely a subject of research in university and government labs; they have found a variety of applications at industrial scale, where their market is predicted to grow steadily. Nevertheless, many barriers to enhance their performance and further spread their application remain to be overcome. In this Special Issue, we will focus our attention to some of the persistent challenges of micro-/nano-resonators such as nonlinearity, temperature stability, acceleration sensitivity, limits of quality factor, and failure modes that require a more in-depth understanding of the physics of vibration at small scale. The goal is to seek innovative solutions that take advantage of unique material properties and original designs to push the performance of micro-resonators beyond what is conventionally achievable. Contributions from academia discussing less-known characteristics of micro-resonators and from industry depicting the challenges of large-scale implementation of resonators are encouraged with the hopes of further stimulating the growth of this field, which is rich with fascinating physics and challenging problems

Theoretical and experimental development of a ZnO-based laterally excited thickness shear mode acoustic wave immunosensor for cancer biomarker detection

The object of this thesis research was to develop and characterize a new type of acoustic biosensor - a ZnO-based laterally excited thickness shear mode (TSM) resonator in a solidly mounted configuration. The first specific aim of the research was to develop the theoretical underpinnings of the acoustic wave propagation in ZnO. Theoretical calculations were carried out by solving the piezoelectrically stiffened Christoffel equation to elucidate the acoustic modes that are excited through lateral excitation of a ZnO stack. A finite element model was developed to confirm the calculations and investigate the electric field orientation and density for various electrode configurations. A proof of concept study was also carried out using a Quartz Crystal Microbalance device to investigate the application of thickness shear mode resonators to cancer biomarker detection in complex media. The results helped to provide a firm foundation for the design of new gravimetric sensors with enhanced capabilities. The second specific aim was to design and fabricate arrays of multiple laterally excited TSM devices and fully characterize their electrical properties. The solidly mounted resonator configuration was developed for the ZnO-based devices through theoretical calculations and experimentation. A functional mirror comprised of W and SiO2 was implemented in development of the TSM resonators. The devices were fabricated and tested for values of interest such as Q, and electromechanical coupling (K2) as well as their ability to operate in liquids. The third specific aim was to investigate the optimal surface chemistry scheme for linking the antibody layer to the ZnO device surface. Crosslinking schemes involving organosilane molecules and a phosphonic acid were compared for immobilizing antibodies to the surface of the ZnO. Results indicate that the thiol-terminated organosilane provides high antibody surface coverage and uniformity and is an excellent candidate for planar ZnO functionalization. The fourth and final specific aim was to investigate the sensitivity of the acoustic immunosensors to potential diagnostic biomarkers. Initial tests were performed in buffer spiked with varying concentrations of the purified target antigen to develop a dose-response curve for the detection of mesothelin-rFc. Subsequent tests were carried out in prostate cancer cell line conditioned medium for the detection of PSA. The results of the experiments establish the operation of the devices in complex media, and indicate that the acoustic sensors are sensitive enough for the detection of biomolecular targets at clinically relevant concentrations.Ph.D.Committee Chair: William D Hunt; Committee Member: Bruno Frazier; Committee Member: Dale Edmondson; Committee Member: Marie Csete; Committee Member: Peter Edmonson; Committee Member: Ruth O'Rega

Techniques, Circuits and Devices for Noncontact Sensing through Wireless Coupling

Le tecnologie per la misurazione di grandezze fisiche senza contatto sono diventate sempre più centrali in vari settori, che vanno dal monitoraggio industriale alle applicazioni sanitarie. In questo contesto, la tesi si concentra sullo sviluppo e l'implementazione di tecniche innovative, circuiti elettronici e dispositivi per la rilevazione senza contatto. L’analisi presentata all'interno di questa tesi considera lo scenario del rilevamento senza contatto a distanza nel campo elettromagnetico lontano (far-field) e al rilevamento senza contatto di prossimità, sfruttando le interazioni elettromagnetiche in campo vicino (near field). Nell’ambito del rilevamento senza contatto a distanza, la tesi indaga l'uso delle onde elettromagnetiche per il monitoraggio non invasivo del livello di solidi granulari all’interno di silos. Questo sistema, sviluppato impiegando un sensore radar commerciale a onda continua modulata in frequenza, dimostra il potenziale di questa tecnologia nel monitoraggio non invasivo e senza contatto in contesti agricoli e industriali. Considerando invece lo scenario del rilevamento senza contatto di prossimità, la tesi fornisce un'analisi dell'interrogazione senza contatto di sensori passivi e ne presenta diversi approcci e applicazioni. Vengono affrontate le problematiche delle misurazioni senza contatto, proponendo alcune soluzioni per migliorarne l'affidabilità e l'accuratezza, permettendo in particolare di renderle indipendenti dalla distanza di interrogazione. In particolare, la tesi presenta un sistema per la misurazione senza contatto della frequenza di risonanza di risonatori MEMS piezoelettrici. La tecnica proposta sfrutta l'accoppiamento magnetico tra un’unità di interrogazione ed un’unità sensore ed è applicata in modo innovativo per la rilevazione della temperatura, sfruttando le proprietà dei risonatori a disco in nitruro di alluminio (AlN) su silicio sottile piezoelettrico (TPoS) ed una tecnica di interrogazione senza contatto a tempo commutato. Inoltre, la tesi presenta un’etichetta flessibile per la misurazione della temperatura corporea, che combina il rilevamento a contatto della temperatura con una lettura senza contatto dell’unità sensore sfruttandone l'accoppiamento magnetico con un unità di interrogazione. L’etichetta flessibile, che costituisce l'unità sensore, è composta da una bobina induttiva che consente l'accoppiamento magnetico, un condensatore ceramico utilizzato come elemento sensibile alla temperatura, sfruttandone il coefficiente di temperatura della capacità, ed un induttore aggiuntivo utilizzato per rendere la frequenza di risonanza del circuito risonante RLC indipendente dalla flessione dell’etichetta. In modo analogo, le tecniche di interrogazione proposte sono state applicate ad un nuovo metodo per l'interrogazione senza contatto di un sensore induttivo, utilizzato per rilevare target conduttivi. Il sistema proposto presenta una bobina avvolta collegata con un condensatore per formare un circuito LC risonante, la cui frequenza di risonanza cambia quando un target conduttivo viene introdotto nel campo magnetico generato dalla bobina stessa. Attraverso una bobina di interrogazione esterna, accoppiata elettromagneticamente al sensore induttivo, è possibile interrogare senza contatto il sensore induttivo, permettendo quindi la rilevazione a distanza di target conduttivi. Infine, lo studio esposto in questa tesi introduce una tecnica avanzata per l'interrogazione senza contatto di sensori resistivi passivi, sfruttando risonatori a cristallo di quarzo come dispositivo risonante e basandosi sulla stima del fattore di qualità del circuito che costituisce l’unità sensore. Il metodo proposto supera i limiti delle tecniche basate su misure di ampiezza, legati in particolare all'influenza della distanza di interrogazioneNoncontact sensing technologies have become increasingly central in a variety of fields, ranging from industrial monitoring to healthcare applications. In this context, the thesis focuses on the development and implementation of innovative techniques, electronic circuits, and devices for contactless sensing via wireless coupling, responding to the growing interest in noncontact measurement methods. The themes treated in this thesis regard both the scenario of distant noncontact sensing in the electromagnetic far field, and proximate wireless sensing, leveraging on near-field electromagnetic interactions. Each domain is distinctly characterized by its specific technologies, applications, and methodologies, reflecting their operational ranges and fundamental principles. In the domain of distant wireless sensing, the thesis investigates the use of electromagnetic waves for unobtrusive level monitoring of granular solids in silos. This system, developed employing a commercial frequency-modulated continuous-wave radar sensor, demonstrates the potential of this technology in unobtrusive monitoring in agricultural and industrial environments. Considering the proximate wireless sensing domain, the thesis provides an analysis of noncontact interrogation of passive sensors and it presents different approaches and applications. It addresses the challenges and offers solutions for enhancing the reliability and accuracy of contactless measurements, which can be advantageously independent of the interrogation distance. This can path the way to the development of low-cost, disposable and sustainable devices for healthcare and industrial applications. In particular, the thesis presents a system for the noncontact measurement of the resonant frequency of piezoelectric MEMS resonators. The technique exploits magnetic coupling between interrogation and sensor units, and it is innovatively applied for temperature sensing exploiting a thin-film piezoelectric on silicon (TPoS) aluminium nitride (AlN) disk resonators and a contactless interrogation time-gated technique. Furthermore, the thesis presents a flexible patch for body temperature measurement, combining contact sensing with contactless readout, and exploiting magnetic coupling between interrogation and sensor units. The flexible patch, forming the sensor unit, is composed of an inductive coil for magnetic coupling, a ceramic capacitor used as the temperature sensing element exploiting its temperature coefficient of capacitance and an additional inductor to make the resonant frequency of the resulting resonant RLC circuit independent from the bending of the patch. Similarly, interrogation techniques have been applied to a novel method for contactless interrogation of an inductive sensor used for detecting conductive targets. The system features a solenoidal coil connected with a capacitor to form a resonating LC circuit, whose resonant frequency changes when a conductive target is introduced in the generated magnetic field. An external interrogation coil electromagnetically coupled to the inductive sensor enables the wireless measurement for conductive target detection. Lastly, the study introduces an advanced technique for the contactless interrogation of passive resistive sensors. The novel approach exploits the resonant frequency stability and the high quality factor of a quartz crystal resonator, used as a resonant element, with a series-connected resistor acting as the sensing element. This method overcomes the limitations of amplitude measurements techniques typically affected by the interrogation distance

Flow detectors having mechanical oscillators, and use thereof in flow characterization systems

An improved system (100), resonator flow detector (102) and method for characterizing a fluid sample that includes o injecting a fluid sample into a mobile phase of a flow characterization system (106), and detecting a property of the fluid sample > or of a component thereof with a flow detector (102) comprising a mechanical resonator (120), preferably one that is operated at a frequency less than about 1 MHz, such as tuning fork resonator

Interactions between molecules and nanostructures using quartz crystal microbalance

The understanding of protein behaviour at the nanoscale is critical for the development of new therapies and biosensing. The assembly of peptides for new therapies are performed on the surface of a biosensor and because of the rough nature of this sample, the characterisation is usually performed on a separate substrate that will provide a higher contrast with a different technique. The ideal scenario is for the same surface to be used in both sensing and characterisation stages. For biosensing, the rough nature of the surface could increase the range of mass measurement for biosensors with micro and nanoscale surfaces. Additionally, the interaction of proteins with nanostructures open the possibility of altering the dynamics of protein adsorption. These changes could be translated to different mechanical properties of the sensed protein. Furthermore, the induced conformational change might allow for a permanent attachment of the protein, increasing the limit of detection of a biosensor. However, the behaviour of proteins with nanoscale features is not well understood. Therefore, the fabrication of nanostructured surfaces along with eliminating such features on QCM biosensors for sensing and characterisation of proteins is pursued in this dissertation. Multiple novel methods of nanofabrication on top of QCM gold electrodes were created using ZnO nanowires (Chapter 1), gold nanoparticles (Chapter 2), and e-beam lithography (Chapter 5). These techniques were further optimised to obtain simple protocols to be followed by any user. Subsequently, optimal surfaces were used for protein adsorption and their results show less protein adsorption than the expected by the area increase of the features (50-70%), suggesting protein conformational changes (spreading) upon binding. The observation of protein conformational changes on nanostructures suggested that the roughness of standard gold QCM electrodes might also play a role in protein adsorption. A novel fabrication process is developed for the transfer of an atomically flat surface of gold onto a QCM Au electrode, the pressure-forming template stripped (PTS) technique. In Chapter 3, the PTS method is presented with the crucial parameters for obtaining an atomically flat gold surface on QCM resonators and their optimisation to obtain a roughness of 0.35 nm ± 0.05 root mean square and a required thickness of 100 nm of Au QCM electrodes. Furthermore, the QCM with PTS electrodes (PTS QCM) is used to adsorb model protein bovine serum albumin (BSA). This is compared against resonators with a standard electrode roughness from different companies, and against resonators build in-house with higher roughness than commercial samples. It is showed by both QCM mass monitoring and AFM of the same PTS QCM sample that BSA adsorption of BSA occurs in a self-assemble like manner, a tightly packed monolayer. More BSA areal mass is adsorbed on PTS QCM (15%) and high roughness QCM (17%) resonators than QCM samples with standard roughness. In contrast with standard QCM, high roughness QCM resonators induce aggregates on the surface increasing the mass adsorbed and obtaining similar areal mass to the tightly packed adsorption on PTS QCM devices.CONACyT (Mexico), SEP (Mexico), Cambridge Trust, Fitzwilliam College

Planar Microwave Sensors for Accurate Measurement of Material Characterization: A Review

Microwave sensor is used in various industrial applications and requires highly accurate measurements for material properties. Conventionally, cavity waveguide perturbation, free-space transmission, open-ended coaxial probe, and planar transmission line technique have been used for characterizing materials. However, these planar transmission lines are often large and expensive to build, further restricting their use in many important applications. Thus, this technique is cost effective, easy to manufacture and due to its compact size, it has the potential to produce sensitivity and a high Q-factor for various materials. This paper reviews the common characteristics of planar transmission line and discusses numerous studies about several designs of the microstrip resonator to improve the sensor performance in terms of the sensitivity and accuracy. This technique enables its use for several industrial applications such as agriculture and quality control. It is believed that previous studies would lead to a promising solution of characterizing materials with high sensitivity, particularly in determining a high Q-factor resonator sensor

Development of a novel high resolution and high throughput biosensing technology based on a Monolithic High Fundamental Frequency Quartz Crystal Microbalance (MHFF-QCM). Validation in food control

Tesis por compendio[ES] La sociedad actual demanda un mayor control en la seguridad y calidad de los alimentos que se consumen. Esta preocupación se ve reflejada en los diferentes planes estatales y europeos de investigación científica, los cuales, plantean la necesidad de innovar y desarrollar nuevas técnicas analíticas que cubran los requerimientos actuales. En el presente documento se aborda el problema de la presencia de residuos químicos en la miel. El origen de los mismos se debe, fundamentalmente, a los tramientos veterinarios con los que se tratan enfermedades y parásitos en las abejas, y a los tratamientos agrícolas con los que las abejas se ponen en contacto cuando recolectan el néctar en cultivos próximos a las colmenas. La Agencia Europea de Seguridad Alimentaria (EFSA) confirma esta realidad al notificar numerosas alertas sanitarias en la miel. En los últimos años, los métodos de análisis basados en inmunosensores piezoeléctricos se han posicionado como la base de una técnica de cribado muy prometedora, la cual puede ser empleada como técnica complementaria a las clásicas de cromatografía, gracias a su sencillez, rapidez y bajo coste. La tecnología de resonadores High-Fundamental Frequency Quartz Crystal Microbalance with Dissipation (HFF-QCMD) combina la detección directa en tiempo real, alta sensibilidad y selectividad con un fácil manejo y coste reducido en comparación con otras técnicas. Además, está tecnología permite aumentar el rendimiento del análisis mediante el diseño de arrays de resonadores en un mismo sustrato (Monolithic HFF-QCMD). En este documento se presenta el diseño de un array de 24 sensores HFF-QCMD, junto con un cartucho de micro-fluídica que traza diversos microcanales sobre los diferentes elementos sensores, a los que hace llegar la muestra de miel diluida a analizar. El cartucho actúa también como interfaz para realizar la conexión entre el array de resonadores y el instrumento de caracterización de los mismos. Para obtener el máximo partido del array diseñado, se desarrolla un método de medida robusto y fiable que permite elevar la tasa de adquisición de datos para facilitar la toma de registros eléctricos de un elevado número de resonadores de forma simultánea, e incluso en varios armónicos del modo fundamental de resonancia. La gran sensibilidad de la tecnología HFF-QCMD a los eventos bioquímicos a caracterizar se extiende también a otro tipo eventos externos, como son los cambios de temperatura o presión, lo que es necesario minimizar con el fin de reducir el impacto que estas perturbaciones no deseadas provocan en la estabilidad y fiabilidad de la medida. Con este fin, se desarrolla un algoritmo de procesado de señal basado en la Discrete Transform Wavelet (DTW). Finalmente, todos los desarrollos tecnológicos realizados se validan mediante la implementación de un inmunoensayo para la detección simultánea, en muestras de mieles reales, de residuos químicos de naturaleza química muy diferente, a saber, el fungicida tiabendazol y el antibiótico sulfatiazol.[CA] La societat actual demanda un major control en la seguretat i qualitat dels aliments que es consumeixen. Aquesta preocupació es veu reflectida en els diferents plans estatals i europeus d'investigació científica, els quals, plantegen la necessitat d'innovar i desenvolupar noves tècniques analítiques que cobrisquen els requeriments actuals. En el present document s'aborda el problema de la presència de residus químics en la mel. L'origen dels mateixos es deu, fonamentalment, als tractaments veterinaris amb els quals es tracten malalties i paràsits en les abelles, i als tractaments agrícoles amb els quals les abelles es posen en contacte quan recol·lecten el nèctar en cultius pròxims als ruscos. L'Agència Europea de Seguretat Alimentària (EFSA) confirma aquesta realitat notificant nombroses alertes sanitàries en la mel. En els últims anys, els mètodes d'anàlisis basades en immunosensors piezoelèctrics s'han posicionat com la base d'una tècnica de garbellat molt prometedora, la qual pot ser emprada com a tècnica complementària a les clàssiques de cromatografia, gràcies a la seua senzillesa, rapidesa i baix cost. La tecnologia de ressonadors High-Fundamental Frequency Quartz Crystal Microbalance with Dissipation (HFF-QCMD) combina la detecció directa en temps real, alta sensibilitat i selectivitat amb un fàcil maneig i cost reduït en comparació amb altres tècniques. A més, està tecnologia permet augmentar el rendiment del anàlisi mitjançant el disseny d'arrays de ressonadors en un mateix substrat (Monolithic HFF-QCMD). En aquest document es presenta el disseny d'un array de 24 sensors HFF-QCMD, juntament amb un cartutx de microfluídica que estableix diversos microcanals sobre els diferents elements sensors, als quals fa arribar la mostra de mel diluïda a analitzar. El cartutx actua també com a interfície per a realitzar la connexió entre l'array de ressonadors i l'instrument de caracterització d'aquests. Per a traure el màxim partit a l'array dissenyat, es desenvolupa un mètode de mesura robust i fiable que permet elevar la taxa d'adquisició de dades per a facilitar la presa de registres elèctrics d'un elevat nombre de ressonadors de manera simultània, i fins i tot en diversos harmònics del mode fonamental de ressonància. La gran sensibilitat de la tecnologia HFF-QCMD als esdeveniments bioquímics a caracteritzar s'estén també a un altre tipus esdeveniments externs, com són els canvis de temperatura o pressió, la qual cosa és necessari minimitzar amb la finalitat de reduir l'impacte que aquestes pertorbacions no desitjades provoquen en l'estabilitat i fiabilitat de la mesura. A aquest efecte, es desenvolupa un algorisme de processament de senyal basat en la Discrete Transform Wavelet (DTW). Finalment, tots els desenvolupaments tecnològics realitzats es validen mitjançant la implementació d'un immunoassaig per a la detecció simultània, en mostres de mel reals, de residus químics de naturalesa química molt diferent, a saber, el fungicida tiabendazol i l'antibiòtic sulfatiazol.[EN] Currently, society demands greater control over the safety and quality of the food consumed. This concern is reflected in the different states and European plans for scientific research, which establish the necessity to innovate and develop new analytical techniques that meet current requirements. This document addresses the problem of the presence of chemical residues in honey. Its origin is fundamentally due to the veterinary treatments against diseases and parasites in bees, and also to the agricultural treatments with which the bees come into contact when they collect the nectar in crops close to the hives. The European Food Safety Agency (EFSA) confirms this reality by notifying numerous health alerts in honey. In recent years, analysis methods based on piezoelectric immunosensors have been positioned as the basis of a very promising screening technique, which can be used as a complementary technique to the classic chromatography, thanks to its simplicity, speed and low cost. High-Fundamental Frequency Quartz Crystal Microbalance with Dissipation (HFF-QCMD) resonator technology combines direct real-time detection, high sensitivity and selectivity with easy handling and low cost compared to other techniques. In addition, this technology allows increasing the performance of the analysis through the design of resonator arrays on the same substrate (Monolithic HFF-QCMD). This document presents the design of an array of 24 HFF-QCMD sensors, together with a microfluidic cartridge that establish various microchannels on the different sensor elements, to provide them the diluted honey sample to be analyzed. The cartridge also acts as an interface to make the connection between the array of resonators and the characterization instrument. To get the most out of the designed array, a robust and reliable measurement method has been developed that allows increasing the data acquisition rate to facilitate electrical parameters readout from a high number of resonators simultaneously, and even in several harmonics of the fundamental resonance mode. The great sensitivity of the HFF-QCMD technology to the biochemical events to be characterized also is extended to other types of external events, such as changes in temperature or pressure, which must be minimized in order to reduce the impact that these unwanted disturbances cause in the stability and reliability of the measurement. To this end, a signal processing algorithm based on the Discrete Transform Wavelet (DTW) is developed. Finally, all the technological developments carried out are validated through the implementation of an immunoassay for the simultaneous detection, in real honey samples, of chemical residues of very different chemical nature, namely, the fungicide thiabendazole and the antibiotic sulfathiazole.The authors would also like to thank Jorge Martínez from the Laboratory of High Frequency Circuits (LCAF) of the Universitat Politècnica de València (UPV) for assistance with profilometry, and Manuel Planes, José Luis Moya, Mercedes Tabernero, Alicia Nuez and Joaquin Fayos from the Electron Microscopy Services of the UPV for helping with the AFM, and SEM measurements. M.Calero is the recipient of the doctoral fellowship BES-2017-080246 from the Spanish Ministry of Economy, Industry and Competitiveness (Madrid, Spain). This research was funded by Spanish Ministry of Economy and Competitiveness with FEDER funds (AGL 2016-77702-R) and European Commission Horizon 2020 Programme (Grant Agreement number H2020-FETOPEN-2016-2017/737212-CATCH-U-DNA - Capturing non-Amplified Tumor Circulating DNA with Ultrasound Hydrodynamics) for which the authors are grateful. Román Fernández is with the Center for Research and Innovation in Bioengineering (Ci2B), Universitat Politècnica de València, València, Spain and with Advanced Wave Sensors S.L., Paterna, València, Spain. (e-mail: [email protected]); Yolanda Jiménez, Antonio Arnau and María Calero are with the Center for Research and Innovation in Bioengineering (Ci2B), Universitat Politècnica de València, València, Spain; Ilya Reiviakine is with Advanced Wave Sensors S.L., Paterna, Valencia, Spain and with the Department of Bioengineering, University of Washington, Seattle, WA, 98150 USA; María Isabel Rocha-Gaso and José Vicente García are with Advanced Wave Sensors S.L., Paterna, València, Spain.Calero Alcarria, MDS. (2022). Development of a novel high resolution and high throughput biosensing technology based on a Monolithic High Fundamental Frequency Quartz Crystal Microbalance (MHFF-QCM). Validation in food control [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/182652TESISCompendi

Development of an Electrical Interface for A Lateral Field Excited Sensor System

Sensor systems are utilized to provide critical information to an end user which may range from a physician in a heath care facility to a soldier in a battle field environment. The heart of the sensor system is the sensing platform, examples of which include semiconductor, piezoelectric and optical devices. The responses of these sensors must be converted into a format that the user can read and interpret. This conversion is achieved through integrating the sensing platform with an electrical interface. The focus of this thesis is the development of the first electrical interface for Quartz Crystal Microbalance (QCM) sensors in the Lateral Field Excitation (LFE) configuration. Common techniques used for interfacing with thickness field excitation (TFE) QCM devices include impedance-based systems, oscillator systems, and phase-mass based systems. Although oscillators have been successfully designed for TFE QCMs, attempts to develop an oscillator-based interface system for the LFE QCMs operating in air and vacuum media have been unsuccessful. A comparative study of LFE and TFE sensors operating in air and vacuum media was conducted to determine the reason why these interfaces do not work with LFE QCMs. It was concluded that compared to TFE sensors LFE sensors have higher motional resistance, Rm, and narrower separation between the series and parallel resonant frequencies, which inhibited oscillation. To identify an optimum configuration for the 6MHz LFE sensor based on the sensor\u27s impedance response, 45 different configurations for the LFE sensor were fabricated and tested. Based on the conclusions of the comparative study and further investigation into QCM electrical interfaces, two electrical interface systems were investigated for the chosen LFE: the Balanced Bridge Oscillator (BBO) and the Phase Shift Monitoring system. The BBO, a type of frequency tracking system, was selected as the parallel capacitance seen by the sensor can be compensated for, improving the bandwidth of the sensors impedance response. This circuit can be tuned to match the LFE response, and incorporate automatic gain control. However, The fabricated BBO was unable to achieve a stable oscillation with current LFE devices. The Phase-Shift Monitoring system, which is based on the Phase-Mass characterization method, utilizes an external signal to excite the sensor, and the change in the phase shift of the sensor is tracked as a load is applied to it. The system outputs two DC signals corresponding to the detected change in phase-shift and signal amplitude. The Phase-Mass Monitoring system was tested using both liquid and solid loading with the LFE sensor, and was able to consistently detect masses in the 10s of micrograms range. When the LFE was loaded with 52μg in air, the system output 7.45mV with a tolerance of ±0.6mV. The Phase-Shift Monitoring system is the first electrical interface to be successfully integrated with the LFE sensor platform in air and vacuum media, where oscillator-based systems have been unsuccessful. Further work and testing on the system are required to fully characterize the phase-mass relationship of the LFE, as well as developing the system for commercialization

Modeling and Experimental Study of Bulk Acoustic Wave Resonator Sensor

Bulk acoustic wave (BAW) resonator as one of the simplest acoustic device, has been proven a most powerful tool for sensor applications with the advantage of precise frequency counting in electronic measurement. Meanwhile, with the improvement of device fabrication and material growth techniques, the resonator can be made with very small size, especially thin film bulk acoustic wave resonators (FBARs) based on ZnO and AlN have been attracted much interest for sensor application due to their high sensitivity induced by high resonance frequency. In this thesis, research focus is on the modeling and experimental study of bulk acoustic wave resonator sensor.Quartz thickness shear mode (TSM) resonator is adopted to characterize the viscoelastic properties of polymer nanocomposite thin films deposited on the resonators surface. The input electric admittance of multilayer loaded TSM acoustic wave resonator is firstly derived using transfer matrix method by taking into account the acoustic wave impedance of the polymeric layer. Nanocomposite thin films of multi-wall carbon nanotubes (MWCNTs) in copolymers of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) are deposited on TSM resonators through spin-on coating processing. The electric impedance spectra of the unloaded and loaded acoustic wave resonators are measured experimentally, and a data fitting approach is applied to extract the properties of the polymer nanocomposites films. It has been found that the thickness of the polymer layer plays a very important role in the extraction of the viscoelastic properties of the films through data fitting, and the reinforcement of the elastic shear modulus of polymer nanocomposite films is not significant. Quartz TSM resonator is also investigated for in-situ and real time detection of liquid flow rate. A 5MHz TSM quartz resonator is edge-bonded to the sensor mounting port of a special flow chamber with one side exposed to the flowing liquid and other side exposed to air. The fundamental, 3rd, 5th, 7th, and 9th resonant frequency shift due to flow pressure is found to be around 920 (Hz), 3572 (Hz), 5947 (Hz), 8228 (Hz) and 10300 (Hz) for flow rate variation from 0 to 3000 ml/min, which has a corresponding Reynolds number change from 0 to 822. Both theoretical and experimental investigation shows the resonant frequency shifts of different modes are quadratic with flow rate. The results indicate that quartz TSM resonators can be used for flow sensors with characteristics of simplicity, fast response, and good repeatability.FBARs based on c-axis tilted ZnO and AlN thin films have been theoretically analyzed. Material properties including elastic, dielectric and piezoelectric coefficients, bulk wave properties including acoustic velocity and electromechanical coupling coefficient, and impedance of FBARs are calculated and show strong dependence on the tilt angle of c-axis(¦È).Besides ¦È=90¡ã pure thickness shear mode occurs at 43¡ãfor ZnO and 46.1¡ãfor AlN, besides ¦È=0¡ã pure thickness longitudinal mode occurs at 65.4¡ã for ZnO and 67.1¡ãfor AlN. The electromechanical coupling coefficient of shear mode has a maximum value 13.1% at ¦È=33.3¡ãfor ZnO, and 6.5% at ¦È=34.5¡ãfor AlN; the maximum electromechanical coupling coefficient of longitudinal mode occurs at ¦È=0¡ãwith a value of 8.5% for ZnO, and 6% for AlN. The simulation results show that c-axis tilted ZnO and AlN thin films can provide more options for filter design and sensor application