UHF Field-Effect-Transistor Mixer of High Dynamic Range.

1969 ◽  
Author(s):  
David M. Hodsdon
Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 439 ◽  
Author(s):  
Kyung Ho Kim ◽  
Sang Hun Lee ◽  
Sung Eun Seo ◽  
Joonwon Bae ◽  
Seon Joo Park ◽  
...  

Stress biomarkers such as hormones and neurotransmitters in bodily fluids can indicate an individual’s physical and mental state, as well as influence their quality of life and health. Thus, sensitive and rapid detection of stress biomarkers (e.g., cortisol) is important for management of various diseases with harmful symptoms, including post-traumatic stress disorder and depression. Here, we describe rapid and sensitive cortisol detection based on a conducting polymer (CP) nanotube (NT) field-effect transistor (FET) platform. The synthesized polypyrrole (PPy) NT was functionalized with the cortisol antibody immunoglobulin G (IgG) for the sensitive and specific detection of cortisol hormone. The anti-cortisol IgG was covalently attached to a basal plane of PPy NT through an amide bond between the carboxyl group of PPy NT and the amino group of anti-cortisol IgG. The resulting field-effect transistor-type biosensor was utilized to evaluate various cortisol concentrations. Cortisol was sensitively measured to a detection limit of 2.7 × 10−10 M (100 pg/mL), with a dynamic range of 2.7 × 10−10 to 10−7 M; it exhibited rapid responses (<5 s). We believe that our approach can serve as an alternative to time-consuming and labor-intensive health questionnaires; it can also be used for diagnosis of underlying stress-related disorders.


2014 ◽  
Vol 1586 ◽  
Author(s):  
Masaki Hasegawa ◽  
Yuki Hirayama ◽  
Yasuhide Ohno ◽  
Kenzo Maehashi ◽  
Kazuhiko Matsumoto

ABSTRACTWe confirmed a specific detection of immunoglobulin E(IgE) by using an aptamer immobilized reduced graphene oxide(rGo) field effect transistor(FET). A detection limit and dynamic range were estimated 8.1 ng/ml and 10000 respectively. These characteristics are comparable with current fluorescent markers. Although a mobility of rGo FET was around 5 cm2/V.sec, and this is two to three orders lower than mechanically exfoliated pristine graphene FET, a sensitivity of it was only one order lower than using pristine graphene.


2019 ◽  
Vol 40 (7) ◽  
pp. 703-719 ◽  
Author(s):  
Przemyslaw Zagrajek ◽  
Sergey N. Danilov ◽  
Jacek Marczewski ◽  
Michal Zaborowski ◽  
Cezary Kolacinski ◽  
...  

2009 ◽  
Vol 94 (9) ◽  
pp. 093511 ◽  
Author(s):  
W. P. Wang ◽  
Y. Hou ◽  
N. Li ◽  
Z. F. Li ◽  
X. S. Chen ◽  
...  

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Shokoofeh Sheibani ◽  
Luca Capua ◽  
Sadegh Kamaei ◽  
Sayedeh Shirin Afyouni Akbari ◽  
Junrui Zhang ◽  
...  

AbstractCortisol is a hormone released in response to stress and is a major glucocorticoid produced by adrenal glands. Here, we report a wearable sensory electronic chip using label-free detection, based on a platinum/graphene aptamer extended gate field effect transistor (EG-FET) for the recognition of cortisol in biological buffers within the Debye screening length. The device shows promising experimental features for real-time monitoring of the circadian rhythm of cortisol in human sweat. We report a hysteresis-free EG-FET with a voltage sensitivity of the order of 14 mV/decade and current sensitivity up to 80% over the four decades of cortisol concentration. The detection limit is 0.2 nM over a wide range, between 1 nM and 10 µM, of cortisol concentrations in physiological fluid, with negligible drift over time and high selectivity. The dynamic range fully covers those in human sweat. We propose a comprehensive analysis and a unified, predictive analytical mapping of current sensitivity in all regimes of operation.


1986 ◽  
Vol 133 (1) ◽  
pp. 26
Author(s):  
J. Mellis ◽  
G.R. Adams ◽  
K.D. Ward

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