Acoustic wave liquid-phase-based microsensors

Josse, Fabien

doi:10.1016/0924-4247(94)00805-1

Cited by 36 publications

(9 citation statements)

References 37 publications

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“…For example, there have been reports that when one side of the crystal is facing a liquid f p , but not f s , is affected by the conductivity of the liquid. 9,10 It should be noted that the majority of the equations used to relate the frequency and dissipation factor responses of a QCM to a mass or liquid loading have been derived assuming ͑often implicitly͒ that the crystal is oscillating under short-circuit ͑series mode͒ conditions. In this work, we describe a simple setup that allows the simultaneous measurement of the series resonant frequency and the series dissipation factor.…”

Section: Introductionmentioning

confidence: 99%

A simple setup to simultaneously measure the resonant frequency and the absolute dissipation factor of a quartz crystal microbalance

Rodahl

Kasemo

1996

Review of Scientific Instruments

314

272

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An experimental setup is described that can simultaneously measure the absolute dissipation factor and the resonant frequency of a short-circuited quartz crystal microbalance. The crystal is driven at approximately its resonant frequency by a signal generator which is intermittently disconnected by a relay, causing the crystal oscillation amplitude to decay exponentially. The decay is measured using a ferrite toroid transformer. One of the crystal leads is fed through the center of the ferrite toroid and thereby acts as the primary winding of the transformer. The secondary winding of the transformer is connected to a digitizing oscilloscope which records the decay of the crystal oscillation. From the recorded decay curve, the absolute dissipation factor ͑calculated from the decay time constant͒ and the series resonant frequency of the freely oscillating crystal are obtained. Alternatively, the dissipation factor and resonant frequency can be measured for the crystal oscillating under open-circuit conditions, i.e., in the parallel mode. The measurements are automated.

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Section: Introductionmentioning

confidence: 99%

A simple setup to simultaneously measure the resonant frequency and the absolute dissipation factor of a quartz crystal microbalance

Rodahl

Kasemo

1996

Review of Scientific Instruments

314

272

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show abstract

“…The frequency response of the MARS device to the viscous loading of added liquids is a key comparator to the behavior of other acoustic sensors. − 5657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914915916917918919920921922923924925926927928929930931932933934935936937938939940941942943944945946947948949950951952953954955956957958959960961962963964965966967968969970971972973974975976977978979980981982983984985986987988989990991992993994995996997998999100010011002100310041005100610071008100910101011101210131014101510161017101810191020102110221023102410251026102710281029103010311032103310341035...…”

Section: Resultsunclassified

“…However, these waves are generated by magnetic direct generation in MARS and by piezoelectric effects in QCM and are of different horizontal geometries, being radial in MARS and unidirectional in QCM. Compared to the QCM, the MARS device has at least twice the mass loading sensitivity (Hz/ng·mm -2 ), a 100-fold higher sensitivity to viscosity changes, a broader bandwidth (MHz) and range of operating frequencies, and zero effect of solution conductivity . A key feature distinguishing MARS is the ability to tune the frequency of operation by selecting higher harmonics.…”

Section: Discussionmentioning

confidence: 99%

A Strategy for Chemical Sensing Based on Frequency Tunable Acoustic Devices

2001

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A new acoustic sensor geometry, the magnetic acoustic resonant sensor (MARS), is described. The device comprises a circular 0.5-mm-thick resonant plate fabricated from a wide variety of nonpiezoelectric materials and coated on the underside with a 2.5-microm-thick aluminum film. Harmonic radial shear waves over at least a 2 orders of magnitude frequency range can be induced in the resonant plate by enhanced magnetic direct generation using a noncontacting rf coil and NdFeB magnet. Mass loading with adherent aluminum films produced frequency changes of 106 Hz/nm (40.8 Hz/ng-mm(-2)), while contact with viscous fluids resulted in maximum changes of 15 446 Hz/cP. At an operating frequency of 50 MHz, the device detected viscosity changes as low as 0.0006 cP. The adsorption of proteins such as human IgG and the binding of a complementary antigen, goat anti-human IgG, on the upper nonmetallized surface of the device has been monitored with a detection limit of approximately 75 ng/mL. The binding of substrates and allosteric effectors to glycogen phosphorylase b has provided evidence that the device is very sensitive to viscoelastic changes in adsorbed proteins. The MARS device generates radial shear acoustic waves over a broad bandwidth that are unaffected by the conductivity of the solution. These results suggest that simple metal, glass, crystalline, or polycrystalline plates can be used as a new type of tunable acoustic immunosensor.

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“…The results indicate that viscoelastic effects of the coating, known to oppose mass loading, may have been important for both the dextran and the the XP-5 films. The theoretical expression for the mass sensitivity factor S m for APMs on ZX-LiNbO 3 is , where ω is the angular frequency of the mode, V P is its unperturbed phase velocity, ρ f and C ij f are the mass density and viscoelastic constant of the film, respectively, and U i represents the unperturbed acoustic displacement amplitudes associated with the acoustic mode.…”

Section: Resultsmentioning

confidence: 99%

Multifrequency Evaluation of Different Immunosorbents on Acoustic Plate Mode Sensors

et al. 1996

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Previous studies of acoustic plate modes on ZX-LiNbO3 have indicated that practical mass-sensitive immunosensors can be implemented by using devices with higher frequencies of operation and/or by improving techniques for the immobilization of antibodies. However, it is also known from these studies that the viscoelastic properties of aminosilane films, used for the covalent immobilization of antibodies on the crystal surface, cannot be ignored in the sensor response. In the present work, in an attempt to study the effect of viscoelasticity of the binding film, three different films with different viscoelasticity and binding capacities, an aminosilane, a dextran, and a poly-(etherurethane)-based immunosorbent (XP-5), were prepared on the sensor surface for the immobilization of antibodies. Immunochemical reactions were monitored by the acoustic plate mode sensor at three different frequencies, thus allowing the direct observation of the frequency dependence of mass sensitivity with different films. Depending on the type of immunosorbent, the sensitivity at the third harmonic was enhanced by a factor of 2-5 with respect to the fundamental response. A third acoustic mode at a closely spaced frequency to the third harmonic yielded lower sensitivity values, which indicates that sensitivity depends not only on the frequency of device operation but also on particle displacement amplitude and components of the selected wave. Since antigen binding capacities of the different immunosorbents were determined independently by a modified ELISA test, sensor responses can also be correlated to the immunosorbent structure, and hence the viscoelastic properties. A dual delay line configuration was used which compensates for second-order effects such as temperature variations and nonspecific adsorption.

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Acoustic wave liquid-phase-based microsensors

Cited by 36 publications

References 37 publications

A simple setup to simultaneously measure the resonant frequency and the absolute dissipation factor of a quartz crystal microbalance

A simple setup to simultaneously measure the resonant frequency and the absolute dissipation factor of a quartz crystal microbalance

A Strategy for Chemical Sensing Based on Frequency Tunable Acoustic Devices

Multifrequency Evaluation of Different Immunosorbents on Acoustic Plate Mode Sensors

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