Tough hydrogels, polymeric network structures with excellent mechanical properties (such as high stretchability and toughness), are emerging soft materials. Despite their remarkably mechanical features, tough hydrogels exhibit two flaws (freezing around the icing temperatures of water and drying under arid conditions). Inspired by cryoprotectants (CPAs) used in the inhibition of the icing of water in biological samples, a versatile and straightforward method is reported to fabricate extreme anti-freezing, non-drying CPA-based organohydrogels with long-term stability by partially displacing water molecules within the pre-fabricated hydrogels. CPA-based Ca-alginate/polyacrylamide (PAAm) tough hydrogels were successfully fabricated with glycerol, glycol, and sorbitol. The CPA-based organohydrogels remain unfrozen and mechanically flexible even up to -70 °C and are stable under ambient conditions or even vacuum.

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Tough protein organohydrogels are fabricated by applying a solvent displacement-induced toughening (SDIT) strategy. By one-step SDIT, relatively weak and brittle protein hydrogels change to protein organohydrogels with remarkably high performance in anti-freezing, non-drying, topological healing, thermal plasticizing, mechanical toughness and stretchability.

temperature-resistant hydrogels, hydrogels which are freezing-and dehydration-resistant, have garnered considerable attention in the scientific community as they extend the rage of application of hydrogels to arid and/or cold environments. Besides, these hydrogels exhibit tunable conductivity and mechanical performance while offering excellent biocompatibility and flexibility, making them interesting candidates for flexible and wearable electronics and (bio)sensors. Several biomimetic strategies were developed to fabricate anti-freezing and anti-dehydration hydrogels with a diversity of merits, such as high strain resistance and conductivity, even at sub-zero temperatures, and employed as (bio)sensors, electrodes, and energy-storage devices. This review summarizes the recent advances in the preparation and application of temperatureresistant hydrogels, indicates issues of the state-of-the-art hydrogels, and offers potential future research directions.

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Dissolved reactive phosphorus (DRP) is the most available P form in sediments and often directly controls phytoplankton blooms in aquatic systems. In this study, a novel procedure was developed for two-dimensional (2D) measurement of DRP in sediments at a spatial resolution of 0.45 mm using the diffusive gradients in thin films (DGT) technique with a revised high-capacity binding phase (Zr oxide gel). This procedure involves DGT uptake of P in sediments, 2D slicing of the binding gel on a 0.45 × 0.45-mm grid system, elution of P from each gel square with 1 M NaOH, and microcolorimetric determination of DRP in each eluted solution using 384-microwell plates. Measurements of DRP via this procedure were tested in homogeneous solutions and sediments and produced an acceptable error (<20% relative standard deviation) for the analysis once the accumulated mass of P in each gel square reached 1.2 μg cm(-2). This method was successfully applied to produce 2D images of the DRP distribution in sediments with and without the influence of tubificid worm bioturbation, revealing a much more pronounced and localized impact from tubificid worms than that found using a one-dimensional measurement of pore water DRP concentrations at 1-cm resolution.

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