journal article

Journal Article

Text

Analytical Chemistry. 2019, 91(15), p. 9398-9402

Ultrahigh-frequency, wireless mems qcm biosensor for direct, label-free detection of biomarkers in a large amount of contaminants

American Chemical Society

English

Text

2019-08-06

https://doi.org/10.1021/acs.analchem.9b01414

Kentaro Noi, Arihiro Iwata, Fumihito Kato, and Hirotsugu Ogi. Ultrahigh-frequency, wireless mems qcm biosensor for direct, label-free detection of biomarkers in a large amount of contaminants. Analytical Chemistry, 2019, 91(15), 9398-9402. ©2019 American Chemical Society. https://doi.org/10.1021/acs.analchem.9b01414.

Label-free biosensors, including conventional quartz-crystal-microbalance (QCM) biosensors, 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 when the quartz resonator is thinned, which also makes the resonance frequency higher, causing high-speed surface movement. Contaminants weakly (nonspecifically) interact with the quartz surface, but they fail to follow the fast surface movement and cannot be detected as the loaded mass. The targets are, however, 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 have developed a MEMS QCM biosensor in which an AT-cut quartz resonator, 26 μm thick, is packaged without fixing, and we demonstrate this phenomenon by comparing the frequency changes of the 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 to the label-free and sandwich-free, direct detection of C-reactive protein (CRP) in serum and confirmed its applicability.

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Analytical Chemistry, © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.analchem.9b01414.

84141

Ultrahigh-frequency, wireless mems qcm biosensor for direct, label-free detection of biomarkers in a large amount of contaminants

American Chemical Society

English

2019-08-06

Analytical Chemistry

91

15

9398

9402

https://doi.org/10.1021/acs.analchem.9b01414

31264405

https://hdl.handle.net/11094/84141