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标题：Portable biosensor for monitoring cortisol in low-volume perspired human sweat
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作者：David Kinnamon ; Ramesh Ghanta ; Kai-Chun Lin 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2017
卷号：7
期号：1
DOI：10.1038/s41598-017-13684-7
语种：English
出版社：Springer Nature
摘要：A non-faradaic label-free cortisol biosensor was demonstrated using MoS2 nanosheets integrated into a nanoporous flexible electrode system. Low volume (1-5 μL) sensing was achieved through use of a novel sensor stack design comprised of vertically aligned metal electrodes confining semi-conductive MoS2 nanosheets. The MoS2 nanosheets were surface functionalized with cortisol antibodies towards developing an affinity biosensor specific to the physiological relevant range of cortisol (8.16 to 141.7 ng/mL) in perspired human sweat. Sensing was achieved by measuring impedance changes associated with cortisol binding along the MoS2 nanosheet interface using electrochemical impedance spectroscopy. The sensor demonstrated a dynamic range from 1-500 ng/mL with a limit of detection of 1 ng/mL. A specificity study was conducted using a metabolite expressed in human sweat, Ethyl Glucuronide. Continuous dosing studies were performed during which the sensor was able to discriminate between four cortisol concentration ranges (0.5, 5, 50, 500 ng/mL) for a 3+ hour duration. Translatability of the sensor was shown with a portable form factor device, demonstrating a comparable dynamic range and limit of detection for the sensor. The device demonstrated a R2 correlation value of 0.998 when comparing measurements to the reported impedance values of the benchtop instrumentation.