Nanomechanical Cantilever Array Sensors

Lang, Hans Peter; Hegner, Martin; Gerber, Christoph

doi:10.1007/978-3-662-54357-3_15

Cited by 18 publications

(12 citation statements)

References 209 publications

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“…Early application of silicon cantilevers as sensors began when researchers focused on the fact that silicon cantilevers used in atomic force microscopy (AFM) deflect due to changes in relative humidity (RH) [ 1 ]. Micro and nano cantilever-based sensors continue to draw attention, and it has been demonstrated that they are able to detect a variety of biological [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ], physical [ 10 , 11 , 12 ], and chemical analytes [ 13 , 14 , 15 , 16 ]. The microcantilever-based sensing platform is a label-free detection technique that has been proved as a viable alternative solution to conventional sensing systems, such as the assaying procedures [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Cantilever-Based Sensor Utilizing a Diffractive Optical Element with High Sensitivity to Relative Humidity

Grogan

McGovern

Staines

et al. 2021

Sensors

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High-sensitivity and simple, low-cost readout are desirable features for sensors independent of the application area. Micro-cantilever sensors use the deflection induced by the analyte presence to achieve high-sensitivity but possess complex electronic readouts. Current holographic sensors probe the analyte presence by measuring changes in their optical properties, have a simpler low-cost readout, but their sensitivity can be further improved. Here, the two working principles were combined to obtain a new hybrid sensor with enhanced sensitivity. The diffractive element, a holographically patterned thin photopolymer layer, was placed on a polymer (polydimethylsiloxane) layer forming a bi-layer macro-cantilever. The different responses of the layers to analyte presence lead to cantilever deflection. The sensitivity and detection limits were evaluated by measuring the variation in cantilever deflection and diffraction efficiency with relative humidity. It was observed that the sensitivity is tunable by controlling the spatial frequency of the photopolymer gratings and the cantilever thickness. The sensor deflection was also visible to the naked eye, making it a simple, user-friendly device. The hybrid sensor diffraction efficiency response to the target analyte had an increased sensitivity (10-fold when compared with the cantilever or holographic modes operating independently), requiring a minimum upturn in the readout complexity.

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Section: Introductionmentioning

confidence: 99%

Cantilever-Based Sensor Utilizing a Diffractive Optical Element with High Sensitivity to Relative Humidity

Grogan

McGovern

Staines

et al. 2021

Sensors

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show abstract

“…Silicon microcantilever-based sensors have generated great interest in the last decades due to their high sensitivity and their ability to work as label-free sensors capable of detecting numerous target analytes [1][2][3][4][5]. Early work into microcantilever-based sensors began with the investigations of silicon microcantilevers, typically used with atomic force microscopes, as sensor transducers in their own right [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Silicon Microcantilever Sensors to Detect the Reversible Conformational Change of a Molecular Switch, Spiropyan

Grogan

Amarandei

Lawless

et al. 2020

Sensors

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The high sensitivity of silicon microcantilever sensors has expanded their use in areas ranging from gas sensing to bio-medical applications. Photochromic molecules also represent promising candidates for a large variety of sensing applications. In this work, the operating principles of these two sensing methods are combined in order to detect the reversible conformational change of a molecular switch, spiropyran. Thus, arrays of silicon microcantilever sensors were functionalized with spiropyran on the gold covered side and used as test microcantilevers. The microcantilever deflection response was observed, in five sequential cycles, as the transition from the spiropyran (SP) (CLOSED) to the merocyanine (MC) (OPEN) state and vice-versa when induced by UV and white light LED sources, respectively, proving the reversibility capabilities of this type of sensor. The microcantilever deflection direction was observed to be in one direction when changing to the MC state and in the opposite direction when changing back to the SP state. A tensile stress was induced in the microcantilever when the SP to MC transition took place, while a compressive stress was observed for the reverse transition. These different type of stresses are believed to be related to the spatial conformational changes induced in the photochromic molecule upon photo-isomerisation.Sensors 2020, 20, 854 2 of 12 areas ranging from gas, humidity and thermal sensing to novel applications in microbiology, genomics and cancer detection [9][10][11][12][13][14][15]. Innovative microcantilever coatings include polymer brushes-based on phenylboronic acid which have been used to detect glucose binding events [15] and graphene oxide (GO) thin films for high-sensitivity humidity sensing [16]. Other examples involve the use of microcantilever sensors for detection of various diseases through, for example, antibody-antigen interactions for the detection of disease-related C-reactive proteins or for the screening of heart-related diseases by using cardiomyocytes functionalized microcantilevers [17][18][19]. Different fabrication methods for microcantilevers as well as the range of available modification methods in the substrate and sensing layer allow for the realization of different types of cantilever-based sensors [20,21]. An improvement in microcantilevers sensor efficiency of the n-type over p-type silicon cantilevers was demonstrated, and this effect was explained by their greater piezoresistive coefficient [20]. Examples include micromachined silicon cantilever paddle sensors which can be used in high flow rate gas sensing [20,21], and resonant cantilevers for pressure sensing [22].Spiropyrans (SP) are one of the most popular families of photochromic molecules [23,24]. Upon irradiation with UV light, the orthogonal SP isomer converts to the planar merocyanine (MC) form due to the photo-cleavage of the C spiro -O bond. The MC isomer shows a strong absorption band in the visible region due to its conjugation. When the MC is exposed to visible light, the structu...

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“…The availability of silicon in a wide variety of designs and its high Young's modulus make it highly favored among other materials. 36,37 Silicon or silicon nitride are often used to fabricate microcantilevers sensors. Furthermore, there are a number of fabrications processes for producing microcantilevers including photolithography, 36,38 etching, 36,38 and doping.…”

Section: Microcantileversmentioning

confidence: 99%

Review—Measurements of Ionizing Radiations Using Micromechanical Sensors

Alanazi¹,

Almutairi²,

Muthuramamoorthy³

et al. 2022

ECS J. Solid State Sci. Technol.

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We discuss several micromechanical sensor methods for utilizing technologies to detect gamma and beta radiation. The bending and resonance-frequency shifts of microcantilever sensors exhibit high sensitivity to ionizing radiation. Quartz oscillators, as well as microcantilevers coated with different materials, can aid in increasing the sensor sensitivity. Introducing MEMS technology to hydrogen-pressure sensors increased the ability of the sensors to detect low doses of radiation. Quartz tuning forks show excellent sensitivity to radiation and prove to be good candidates for radiation detection. It has been reported as will be discussed in this review that a limit of detection of as low as 0.3 μGy has been possible using micromechanical sensors.

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Nanomechanical Cantilever Array Sensors

Cited by 18 publications

References 209 publications

Cantilever-Based Sensor Utilizing a Diffractive Optical Element with High Sensitivity to Relative Humidity

Cantilever-Based Sensor Utilizing a Diffractive Optical Element with High Sensitivity to Relative Humidity

Silicon Microcantilever Sensors to Detect the Reversible Conformational Change of a Molecular Switch, Spiropyan

Review—Measurements of Ionizing Radiations Using Micromechanical Sensors

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