Superoleophobic/superhydrophilic surfaces have incomparable advantages for oil-water separation and oil droplet manipulation; however, such surfaces are difficult to obtain on the basis of surface tension theory, and existing attempts are either not fully functional or are nondurable. Here, a solution to achieve the combination of superoleophobicity and superhydrophilicity by emphasizing the polar component of surface tension is proposed. The developed surfaces can be flexibly applied to almost any solid substrate and exhibit superoleophobic and instantaneous superhydrophilic property. The surfaces applied to certain substrates can be used for controllable oil transport, oil-water separation, and emulsion demulsification. Furthermore, a novel ferroconcrete-like structure to substantially increase the durability of the developed surfaces without affecting the superwettability is developed. The coated steel meshes preserve the ability of the material to separate oilwater mixtures even after over 400 m abrasion, which can be a significant step toward its widespread application.

Wearable sensors that can conveniently detect cytokine levels in human biofluids are essential for assisting hospitals to maximize the benefits of anti‐inflammatory therapies and avoid cytokine storms. Measurement of cytokine levels in biofluids still remains challenging for existing sensors due to high interference from the background. Here, this challenge is overcome through developing a flexible and regenerative aptameric field‐effect transistor biosensor, consisting of a graphene–Nafion composite film, for detecting cytokine storm biomarkers in undiluted human biofluids. The composite film enables the minimization of nonspecific adsorption and empowers the renewability to the biosensor. With these capabilities, the device is capable of consistently and sensitively monitoring cytokines (e.g., IFN‐γ, an inflammatory and cancer biomarker) in undiluted human sweat with a detection range from 0.015 to 250 nm and limit of detection down to 740 fm. The biosensor is also shown to incur no visible mechanical damage and maintain a consistent sensing response throughout the regenerative (up to 80 cycles) and crumpling (up to 100 cycles) tests. Experimental results demonstrate that the biosensor is expected to offer opportunities for developing wearable biosensing systems for distinguishing acute infectious disease patients and monitoring of patients’ health conditions in daily life.

No abstract

In this article, we have studied the surface nanobubbles on polystyrene (PS)/water interfaces using tapping mode atomic force microscopy (TM-AFM). Detailed bubble coalescence phenomenon of differently sized surface nanobubbles (with lateral size up to about ∼10 μm) was obtained. The quantity of gas molecules, before and after coalescence, was calculated. It was found that after coalescence the quantity of gas molecules was increased by approximately 112.5%. The possible reasons for this phenomenon were analyzed and discussed. Our analysis shows that a reasonable explanation should be an influx of gas into the bubble caused by the depinning of the contact line and the decrease in the inner pressure during bubble coalescence. The factors affecting the coalescence speed of surface bubbles were also discussed. It was found that the coalescence speed of larger bubbles is usually slower than that of the smaller ones. We also noticed that it is uncertain whether a larger or smaller bubble will move first to merge into others. This is due to the combined effects of the contact line and the surface properties. Furthermore, the temporal evolution of surface bubbles was studied. The three-phase contact line of bubbles kept the pinning within the incubation time. This was consistent with the contact line pinning theory, based on which the theoretical lifetime of the surface bubbles in our experiments was calculated to be t(b) ≈ 6.9 h. This value is close to the experimental results. Meanwhile, the faster gas diffusion from the oversized bubbles after 12 h of incubation was observed and analyzed. Our results indicate that a viable stability mechanism for surface nanobubbles would be favored simultaneously by the contact line pinning, gas influx near the contact line from an interfacial gas enrichment (IGE), a thin "contaminant film" around the gas/liquid interface, and even the electrostatic effect.

We present an approach for the label-free detection of cytokine biomarkers using an aptamer-functionalized, graphene field effect transistor (GFET) nanosensor on a flexible, SiO2-coated polymer polyethylene naphthalate (PEN).