Flexible pressure sensors have attracted increasing interest because of their potential applications on wearable sensing devices for human−machine interface connections, but challenges regarding material cost, fabrication robustness, signal transduction, sensitivity improvement, detection range, and operation convenience still need to be overcome. Herein, with a simple, low-cost, and scalable approach, a flexible and wearable pressure-sensing device fabricated by utilizing filter paper as the solid support, poly(3,4-ethylenedioxythiophene) to enhance conductivity, and silver nanoparticles to provide a rougher surface is introduced. Sandwiching and laminating composite material layers with two thermoplastic polypropylene films lead to robust integration of sensing devices, where assembling four layers of composite materials results in the best sensitivity toward applied pressure. This practical pressure-sensing device possessing properties such as high sensitivity of 0.119 kPa −1 , high durability of 2000 operation cycles, and an ultralow energy consumption level of 10 −5 W is a promising candidate for contriving point-of-care wearable electronic devices and applying it to human−machine interface connections.

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An Au@Hcys-C60 nanocomposite for l-histidine sensing.

Selective antioxidant recognition plays a critical role in various scientific and clinical fields, however, development of straightforward detection mechanisms and reduction of technique operation are still barriers nowadays. For example, convenient detection of epigallocatechin gallate (EGCG), the most effective antioxidant among all tea catechins, is highly sought but is severely limited due to the lack of appropriate indicators. To overcome the aforementioned obstacles and to provide more adequate processes that can be employed in antioxidant detection, specific analyte targeting and efficient signal reporting are necessary for the platform design. In this work, a fluorescence "turn on" strategy based on gold nanocluster (AuNC) interface-mediated radical scavenging for selective antioxidant detection is reported. This approach utilizes Lcysteine capped AuNCs with great fluorescence stability as the reporter, where the presence of reactive oxygen species (ROS) generated from the Fenton reaction results in obvious fluorescence quenching. The introduction of antioxidants, that is, EGCG molecules, interestingly, neutralizes the ROS by initiating direct electron and hydrogen atom transfer to eliminate the unpaired free radicals. Besides, the phenolic OH groups and the gallate ring of EGCG also provide a selective and efficient complexation orientation toward Fenton reaction metal ions, where ROS generation is consequently prohibited. This dual-effect phenomenon recovers the originally ROS quenched AuNC fluorescence, which is dependent upon the introduced EGCG quantity. Relying on this fluorescence turn on strategy, the current platform delivers a low detection limit of 1.20 μM with excellent selectivity toward EGCG under the presence of other interfering species. Meanwhile, this approach also provides great accuracy on detecting total antioxidant capacity in commercial green tea samples. This antioxidant fluorometric turn on design therefore gives a more straightforward route on EGCG detection, and its specific recognition capability is very suitable for practical real sample analysis.