Resonance acoustic microbalance with naked-embedded quartz (RAMNE-Q) biosensor fabricated by microelectromechanical-system process

Recent advances in functionalized bio-nanocapsules (BNCs) allow significant sensitivity enhancement in label-free biosensors. It is suggested that the sensitivity amplification is caused by higher binding affinity of BNC to target antibody. We here study the high-affinity interaction mechanism between BNC and antibody with wireless high-frequency QCM biosensors. We first confirm higher affinity between BNC and human immunoglobulin G. We then reveal that the number of the binding sites for the target antibody highly increases by immobilizing BNC molecules on the sensor surface. We finally study the change in the viscoelasticity near the sensor surface using the MEMS wireless QCM biosensor using up to 9th overtone (522 MHz). The inversely determined effective shear modulus on BNC is found to be significantly lower than the standard surface on which the receptor molecules are immobilized. We thus clarify that this surface flexibility will achieve the high affinity with the target antibody.

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“…5-nm Cr and 15-nm Au thin films on both surfaces. (Details of the microchannel and its fabrication procedure are given in Ref 21…”

mentioning

confidence: 99%

Mechanism of affinity-enhanced protein adsorption on bio-nanocapsules studied by viscoelasticity measurement with wireless QCM biosensor

Noi

Iijima

Kuroda

et al. 2020

Jpn. J. Appl. Phys.

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“…Figure 1 shows the components of the hydrogen-gas sensor fabricated using a MEMS process similar to that we developed before [30,31]. The bottom glass substrate was pre-bonded to a silicon layer.…”

Section: Fabrication Of Mems Hydrogen-gas Sensormentioning

confidence: 99%

MEMS hydrogen gas sensor with wireless quartz crystal resonator

Zhou¹,

Kato²,

Nakamura³

et al. 2021

Sensors and Actuators B: Chemical

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A highly sensitive hydrogen-gas sensor fabricated using MEMS technology is presented. The sensor chip consists of glass substrates, silicon substrate, and an AT-cut quartz crystal resonator, which is embedded in the microchannel constructed on the substrates. The quartz resonator has a fundamental resonant frequency of 165 MHz and a 200 nm palladium film deposited on its single surface as the hydrogen-gas sensing material. The MEMS hydrogen-gas sensor operates in a wireless manner by exciting and detecting the resonator vibration using the non-contacting antennas. The curvature induced resonant frequency change of the resonator plate caused by the expansion of the palladium film is used for the detection of the hydrogen gas. We succeeded in improving the hydrogen absorption rate and then the sensitivity for the hydrogen-gas detection by applying the air-plasma treatment method, and clarified the role of palladium oxide in lowering the energy barrier for the hydrogen-atom migration from surface to subsurface with the X-ray photoelectron spectroscopy. Thus sensitivity enhanced MEMS hydrogen-gas sensor exhibits a detection limit of 10 ppm or less at room temperature.

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“…The details of the MEMS process appear in our previous studies. 19,20 The number of micropillars is increased to 59 from 4 of the previous design. 20 Excitation and detection of the shear vibrations of the resonator were performed by the UHF heterodyne spectrometer developed in this study.…”

Section: Wireless Mems Qcm Systemmentioning

confidence: 99%

“…The anodic bonding technique was used to tightly bond glass and Si. The details of the MEMS process appear in our previous studies [19,20]. The number of micropillars is increased to 59 from 4 of the previous design [20].…”

Section: A Wireless Mems Qcm Systemmentioning

confidence: 99%

Ultrahigh-Frequency, Wireless MEMS QCM Biosensor for Direct, Label-Free Detection of Biomarkers in a Large Amount of Contaminants

et al. 2019

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Label-free biosensors, including conventional quartz-crystal-microbalance (QCM) biosensor, are seriously affected by nonspecific adsorption of contaminants involved in analyte solution, and it is exceptionally difficult to extract the sensor responses caused only by the targets. In this study, we reveal that this difficulty can be overcome with an ultrahigh-frequency wireless QCM biosensor. The sensitivity of a QCM biosensor dramatically improves by thinning the quartz resonator, which also makes the resonance frequency higher, causing high-speed surface movement. Contaminants weakly (nonspecifically) interact with the quartz surface, and they fail to follow the fast surface movement and cannot be detected as the loaded mass. The targets are, however, 1 tightly captured by the receptor proteins immobilized on the surface, and they can move with the surface, contributing to the loaded mass and decreasing the resonant frequency. We develop a MEMS QCM biosensor, in which an AT-cut quartz resonator of 26 µm thick is packaged without fixing, and demonstrate this phenomenon by comparing the frequency changes of fundamental (∼64 MHz) and ninth (∼576 MHz) modes.At ultrahigh-frequency operation with the ninth mode, the sensor response is independent of the amount of impurity proteins, and the binding affinity is unchanged. We then applied this method for the label-free and sandwich-free direct detection of C-reactive protein (CRP) in serum, and confirmed its applicability.

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Resonance acoustic microbalance with naked-embedded quartz (RAMNE-Q) biosensor fabricated by microelectromechanical-system process

Cited by 19 publications

References 38 publications

Mechanism of affinity-enhanced protein adsorption on bio-nanocapsules studied by viscoelasticity measurement with wireless QCM biosensor

Mechanism of affinity-enhanced protein adsorption on bio-nanocapsules studied by viscoelasticity measurement with wireless QCM biosensor

MEMS hydrogen gas sensor with wireless quartz crystal resonator

Ultrahigh-Frequency, Wireless MEMS QCM Biosensor for Direct, Label-Free Detection of Biomarkers in a Large Amount of Contaminants

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