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Applications of hydrogels served as drug carriers are severely limited by several main drawbacks of instable network structure, weak mechanical strength, shortage of tissue-adhesive ability, as well as poor anti-frozen performance, especially for some anti-cancer drugs (e.g., lomustine) those should be stored at subzero temperature to maintain their bioactivity. In the present work, a kind of hybrid polyacrylamide/alginate-CaCl2 (PAAm/Alg-Ca) based double-network (DN) hydrogel presented high tensile strength of 61.81 ​± ​5.14 ​kPa, a low water contact angle of 22.5° ​± ​0.8°, and sufficient adhesion on various wet substrates (234.56 ​± ​8.55 ​Pa). More interestingly, pH-responsive swelling behavior, excellent cold-resistance, as well as efficient recoverability at a low temperature of −20 ​°C was shown in such hydrogel. On the basis of biocompatibility result and a sustained drug release behavior using lomustine as a testing model, our proposed PAAm/Alg-Ca based DN hydrogel paves the way for development of anti-cancer drugs cryopreservation and delivery vehicle.

Developing a self‐reporting bioadhesive patch that has strong adhesion to the wet tissues and meanwhile can avoid adhering to the adjacent tissues is a current research difficulty and challenge. In this paper, inspired by the wet adhesion of spider web, slippery surface of Nepenthes, and structural color phenomena of chameleons, a novel structural color medical patch with surface dual‐properties of wet bioadhesion and slipperiness for internal tissue repair based on inverse opal scaffold is presented. The adhesive surface made by poly(acrylic acid)–polyethylene glycol–N‐hydroxysuccinimide ester and gelatin hydrogel can attain tough adhesion to internal wet tissues by absorbing tissue interfacial water and the covalent cross‐linking between the hydrogel and tissue. Besides, the slippery surface made by liquid paraffin infused inverse opal scaffold can avoid adhesion to the adjacent tissues. It is demonstrated that the designed patch can adhere tightly to the defect tissue and improve the tissue repair without adjacent adhesion when applied in a rat model with full‐thickness perforation of the stomach wall. In addition, the responsive structural color can supply a color‐sensing monitoring to evaluate the adhesive and repair process. These features impart the bioinspired patch with great scientific significance and broad clinical application prospects. [ABSTRACT FROM AUTHOR]

Non-compressible hemorrhage control is a big challenge in both civilian life and the battlefield, causing a majority of deaths among all traumatic injury mortalities. Unexpected non-compressible bleeding not only happens in pre-hospital situations but also leads to a high risk of death during surgical processes throughout in-hospital treatment. Hemostatic materials for pre-hospital treatment or surgical procedures for non-compressible hemorrhage control have drawn more and more attention in recent years and several commercialized products have been developed. However, these products have all shown non-negligible limitations and researchers are focusing on developing more effective hemostatic materials for non-compressible hemorrhage control. Different hemostatic strategies (physical, chemical and biological) have been proposed and different forms (sponges/foams, sealants/adhesives, microparticles/powders and platelet mimics) of hemostatic materials have been developed based on these strategies. A summary of the requirements, state-of-the-art studies and commercial products of non-compressible hemorrhage-control materials is provided in this review with particular attention on the advantages and limitations of their emerging forms, to give a clear understanding of the progress that has been made in this area and the promising directions for future generations. [ABSTRACT FROM AUTHOR]