Ion-selective Janus membranes with one-way ionic transport in hypersaline solution approach efficient osmotic energy conversion.

Hydrogels, because of their water-rich nature and soft mechanical characteristics that resemble those of skin tissues, are promising materials for artificial skin. Existing piezoresistive hydrogels combine unique tissue-like and sensory properties, but these materials are often plagued by problems such as poor mechanical properties and the requirement of an external power supply or batteries. Here, a tough and self-powered hydrogel based on a tough polyacrylonitrile hydrogel incorporating ferroelectric poly(vinylidene fluoride) (PAN-PVDF) is reported. The dipolar interactions between the PVDF and PAN chains cause an increase in the best electroactive β-phase PVDF percentage in the composites from 0 to 91.3%; thus, a maximum piezoelectric coefficient d 33 , 30 pC N −1 , was achieved for the hydrogels. Skin-like Young's modulus values (1.33− 4.24 MPa), stretchability (90−175%), and high toughness (1.23 MJ/m 2 ) were achieved simultaneously for the hydrogels. This tough gel is capable of generating an electrical signal output (≈30 mV and ≈2.8 μA) with a rapid response (≈31 ms) due to the stress-induced poling effect. Moreover, the gel can also precisely detect physiological signals (e.g., gesture, pulse, and words). This study provides a simple and efficient method for artificial skin with high toughness, self-power generation capability, fast response, low cost, and tissue-like properties.

Pore me another one: Sub‐nanomolar sequence‐specific DNA detection and sub‐micromolar small‐molecule (ATP) detection was shown by way of self‐assembly and disassembly of DNA superstructures within solid‐state nanopores (see scheme). These DNA structures provide a built‐in amplification mechanism to increase the signal strength and sensitivity. This sensor was also shown to work within complex mixtures, such as mammalian serum.