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α-Synuclein (α-Syn) is a major biomarker of Parkinson's disease (PD). Concentration detection of α-Syn in cerebrospinal fluid and plasma of patients are used as a clue for early PD detection. Herein, we propose a thin-film transistor (TFT) biosensor based on an indium gallium zinc oxide (IGZO) thin film fabricated by the sol-gel method. The IGZO TFT biosensor is used for the early detection of PD after surface functionalization for α-Syn. The surface functionalization worked on the surface of the extended gate indium tin oxide sensing platform instead of the channel layer of TFT. Depending on concentrations of α-Syn in human cerebrospinal fluid and plasma, we diluted six different concentrations of α-Syn for detection, ranging from 1 pg ml−1 to 100 ng ml−1. The result shows that the biosensor exhibits high sensitivity and selectivity for α-Syn, a reliable sensing performance with a sensitivity of 189.9 mV dec−1, and a coefficient of determination R2 of 99.7% between 10 pg ml−1 and 100 ng ml−1. [ABSTRACT FROM AUTHOR]

Mental stress, a human's common emotion that is difficult to recognize and describe, can give rise to serious psychological disorders. Skin and sweat are easily accessible sources of biomarkers and bio-signals that contain information about mental stress. It is challenging for current wearable devices to monitor psychological stress in real-time with a non-invasive manner. Therefore, we have developed a smartwatch integrated with a sweat cortisol sensor and a heart rate variation (HRV) sensor. This smartwatch can simultaneously record the cortisol levels in sweat and HRV index in real time over a long period. The cortisol sensors based on organic electrochemical transistor (OECT) are fabricated by utilizing the Prussian-blue (PB) doped molecular imprinting polymer (MIP) modified gate electrode. The sensor signal current will decrease following the combination of sweat cortisol, due to the blocking of the PBMIP conductive path, demonstrating good sensitivity, selectivity, and stability. The HRV sensor is manufactured by a photoplethysmography method. We have integrated the two sensors into a wearable smartwatch that can match well with the mobile phone APP and the upper computer software. Through the use of this smartwatch, we have observed a negative correlation between cortisol levels in sweat and the HRV index in short-term stressful environments. Our research presents a great progress in real-time and non-invasive monitoring human's stress levels, which promotes not only the stress management, but also better psychological research. [ABSTRACT FROM AUTHOR]

Emulating synaptic behavior using the three-terminal and ion-coupled transistors is considered as a promising strategy for the realization of neuromorphic devices. Meanwhile, one-dimensional (1-D) nanostructures show great potential for the fabrication of flexible electronic devices. In this work, 1-D indium oxide (In2O3) nanofibers were fabricated by the electrospinning (ES), and the flexible and compatible synaptic transistor based on In2O3 nanofibers was integrated on polyimide (PI) substrate. The synaptic behaviors, such as the short-term plasticity (STP) and long-term plasticity (LTP), are simulated by the synaptic transistor with chitosan solution as the gate dielectric. The fabricated synaptic transistor exhibits good biocompatibility and environmental compatibility, and the pattern recognition rate of the simulated device array by the Mixed National Institute of Standards and Technology (MNIST) database of the handwritten digits is confirmed to be as high as 92%. [ABSTRACT FROM AUTHOR]

In this letter, high-performance thin-film transistors (TFTs), with indium oxide (In2O3) as front channel layer, high permittivity ZrO2 as dielectric layer, and aluminum oxide (Al2O3) as passivation layers were integrated by a fully solution process. It is found that the incorporation of Al2O3 passivation layer gives rise to a sharp decrease in the off current (Ioff) and a corresponding increase in the on/off current ratio ($\text{I}_{\text {on}}$ /Ioff) of the TFTs, compared to that without Al2O3 passivation. Furthermore, the thickness effect of the passivation layer on the performance of In2O3 /ZrO2 TFTs has been investigated systematically. The In2O3 /ZrO2 TFTs with optimized Al2O3 passivation layers can be operated at 3 V with high performance, including a high field-effect mobility of 21.22 cm2 /V s, a large $\text{I}_{\text {on}}$ /I off of 107 and a negligible hysteresis (~0V). This work demonstrates an effective strategy for the construction of high performance TFTs by incorporating the passivation layer. [ABSTRACT FROM AUTHOR]

Wearable and Recyclable Epinephrine Biosensors. [Display omitted] • A user-friendly wearable epinephrine sensor system was constructed. • Epinephrine sensor with low detection limit is based on organic transistors. • The detection range covers the concentration of human humoral metabolites. • Recyclability of sensor is suitable for wearable detection in non-invasive way. Tracking fluctuations of epinephrine level is essential for doctors or patients to evaluate the body's condition, but traditional epinephrine detection completely relies on the laboratory instrument. Herein, a wearable and recyclable epinephrine sensor based on the organic electrochemical transistor (OECT) has been developed for rapid, simple, and continuous detection. The molecular imprinting polymer (MIP) is modified on the gate electrode which can recognize the epinephrine molecules, and the voltage drop caused by redox of epinephrine will generate sensing signal. For epinephrine molecules, the boronate affinity binding in MIP and oxidation on electrodes make the sensor have great recyclability. The detection limit of this sensor is 10 pM, which is suitable for humoral metabolites. The sensor can be used for detection at least 20 cycles and recovered by the simple positive voltage cleaning, which is economical for wearable device. The flexible sensors units based on the polydimethylsiloxane (PDMS) are constructed with a matching portable circuit system connecting to the computer and mobile phone APPs. The whole wearable sensor puts up a user-friendly detection method with good recyclability, stability, selectivity and low detection limit for doctors or patients. [ABSTRACT FROM AUTHOR]