Nanotechnology and Precision Engineering
·
2023
·Vol. 6
·期 1
·
IF 3.7
Wu Chen,Li Jiuyan
Being cheap, nondestructive, and easy to use, gas sensors play important roles in the food industry. However, most gas sensors are suitable more for laboratory-quality fast testing rather than for cold-chain continuous and cumulative testing. Also, an ideal electronic nose (E-nose) in a cold chain should be stable to its surroundings and remain highly accurate and portable. In this work, a portable film bulk acoustic resonator (FBAR)-based E-nose was built for real-time measurement of banana shelf time. The sensor chamber to contain the portable circuit of the E-nose is as small as a smartphone, and by introducing an air-tight FBAR as a reference, the E-nose can avoid most of the drift caused by surroundings. With the help of porous layer by layer (LBL) coating of the FBAR, the sensitivity of the E-nose is 5 ppm to ethylene and 0.5 ppm to isoamyl acetate and isoamyl butyrate, while the detection range is large enough to cover a relative humidity of 0.8. In this regard, the E-nose can easily discriminate between yellow bananas with green necks and entirely yellow bananas while allowing the bananas to maintain their biological activities in their normal storage state, thereby showing the possibility of real-time shelf time detection. This portable FBAR-based E-nose has a large testing scale, high sensitivity, good humidity tolerance, and low frequency drift to its surroundings, thereby meeting the needs of cold-chain usage. A compact FBAR-based E-nose was built for gas sensing. A portable field-programmable gate array (FPGA) circuit was used for FBAR frequency testing instead of a traditional PC-sized vector network analyzer (VNA). The sensitivity is 5 ppm to ethylene and 0.5 ppm to isoamyl acetate and isoamyl butyrate, while the detection range is large enough to cover a relative humidity of 0.8. With the help of a reference FBAR and the low FBAR temperature drift, the E-nose reduces the drift caused by its surroundings. Also, the LBL coating method was used to increase the FBAR sensitivity. As a result, the E-nose can realize real-time banana shelf-time detection and can easily discriminate between yellow bananas with green necks and entirely yellow bananas.
研究领域:
食品科学
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传感技术
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农业工程
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产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2025
·
IF 7.7
Zhenyu Wei,Jian-Qiu Huang,Qing-An Huang
Variations in surface-adsorbed mass linearly shift the frequency of piezoelectric sensors, thereby enabling precise measurement of target molecules and facilitating applications in biological and gas sensing. The growing demand for high-precision piezoelectric sensors has spurred research into enhancing sensitivity, including the optimization of sensing materials and resonant modes. This study introduces an approach to enhancing the sensitivity of piezoelectric sensors by utilizing the Exceptional Point (EP) in Parity-Time (PT)-symmetric systems. By capacitively coupling an external LC circuit with a nonlinear negative resistance to the piezoelectric sensor, we transform the sensor into a PT-symmetric system with linear loss and nonlinear gain. Both theoretical and experimental results reveal that when an asymmetric perturbation is applied to the loss resonator, the eigenfrequency of the nonlinear PT-symmetric system biased at the EP exhibits a cube-root singularity. The nonlinearly saturated gain can eliminate the imaginary part of the eigenfrequency and suppress noise. A Film Bulk Acoustic Resonator (FBAR) sensor coated with a cellulose acetate (CA)/graphene oxide (GO) composite was fabricated and characterized. An experimental PT-symmetric system was constructed using the CA/GO-FBAR sensor. The humidity perturbation experiments demonstrate that the PT-symmetric FBAR sensor system achieves a significant sensitivity enhancement under small perturbations. This novel approach overcomes the traditional limitations related to materials and structures for sensitivity enhancement. Furthermore, the concept of PT symmetry could be extended to other piezoelectric sensors for biological and gas sensing, thereby enabling high-sensitivity detection of trace target molecules via the integration of diverse sensitive materials.
研究领域:
传感器与传感技术
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声学谐振器
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光力学与压电电子学
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非厄米物理
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微机电系统（MEMS）
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气体与湿度传感
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纳米材料传感器
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产品关联
DOI
高影响因子
Micromachines
·
2017
·Vol. 8
·期 4
·116
·
IF 1.833
Wenpeng Liu,Hemi Qu,Jizhou Hu,Wei Pang,Hao Zhang,Xuexin Duan
We developed a highly sensitive humidity sensor based on the combination of ultrahigh-frequency film bulk acoustic resonator (FBAR) and nano-assembled polyelectrolyte (PET) thin films. The water molecule absorption efficiency was optimized by forming loosely-packed PET nanostructures. Then, the humidity sensing characteristics were analyzed in terms of sensitivity, linearity, reversibility, stability and detection limit. As a result, PET-coated FBAR exhibits excellent humidity sensitivity of 2202.20 Hz/ppm, which is five orders of magnitude higher than quartz crystal microbalance (QCM). Additionally, temperature dependence was investigated with the result that PET-coated FBAR possessed a higher sensitivity at low temperature. Furthermore, we realized the selective detection of water vapor from volatile organic compounds (VOCs) with respect to the polarity property. Owing to the high sensitivity, miniaturized size and ultrahigh operating frequency, PET-coated FBAR is uniquely favorable as a wireless humidity sensor node to integrate into wireless sensor networks (WSNs).Keywords:humidity sensor;film bulk acoustic resonator (FBAR);ultrahigh frequency;microelectromechanical resonator;nano-assembled polyelectrolyte (PET) thin films;wireless sensor networks (WSNs)
研究领域:
传感器技术
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材料科学
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微机电系统
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产品关联
DOI
高影响因子
BIOSENSORS & BIOELECTRONICS
·
2015
·
IF 6.409
Menglun Zhang,Jingze Huang,Weiwei Cui,Wei Pang,Hao Zhang,Daihua Zhang,Xuexin Duan
Micro/nano scale biosensors integrated with the local adsorption mask have been demonstrated to have a better limit of detection ( LOD ) and less sample consumptions. However, the molecular diffusions and binding kinetics in such confined droplet have been less studied which limited further development and application of the local adsorption method and imposed restrictions on discovery of new signal amplification strategies. In this work, we studied the kinetic issues via experimental investigations and theoretical analysis on microfabricated biosensors. Mass sensitive film bulk acoustic resonator (FBAR) sensors with hydrophobic Teflon film covering the non-sensing area as the mask were introduced. The fabricated masking sensors were characterized with physical adsorption of bovine serum albumin (BSA) and specific binding of antibody and antigen. Over an order of magnitude improvement on LOD was experimentally monitored. An analytical model was introduced to discuss the target molecule diffusion and binding kinetics in droplet environment, especially the crucial effects of incubation time, which has been less covered in previous local adsorption related literatures. An incubation time accumulated signal amplification effect was theoretically predicted, experimentally monitored and carefully explained. In addition, device optimization was explored based on the analytical model to fully utilize the merits of local adsorption. The discussions on the kinetic issues are believed to have wide implications for other types of micro/nano fabricated biosensors with potentially improved LOD .
研究领域:
生物传感器
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分析化学
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纳米技术
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生物物理
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）