Currently, there is growing interest in wearable and biocompatible smart computing and information processing systems that are safe for the human body. Memristive devices are promising for solving such problems due to a number of their attractive properties, such as low power consumption, scalability, and the multilevel nature of resistive switching (plasticity). The multilevel plasticity allows memristors to emulate synapses in hardware neuromorphic computing systems (NCSs). The aim of this work was to study Cu/poly-p-xylylene(PPX)/Au memristive elements fabricated in the crossbar geometry. In developing the technology for manufacturing such samples, we took into account their characteristics, in particular stable and multilevel resistive switching (at least 10 different states) and low operating voltage (<2 V), suitable for NCSs. Experiments on cycle to cycle (C2C) switching of a single memristor and device to device (D2D) switching of several memristors have shown high reproducibility of resistive switching (RS) voltages. Based on the obtained memristors, a formal hardware neuromorphic network was created that can be trained to classify simple patterns.

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Rapidly growing 3D printing of hydrogels requires network materials which combine enhanced mechanical properties and printability. One of the most promising approaches to strengthen the hydrogels consists of the incorporation of inorganic fillers. In this paper, the rheological properties important for 3D printability were studied for nanocomposite hydrogels based on a rigid network of percolating halloysite nanotubes embedded in a soft alginate network cross-linked by calcium ions. Particular attention was paid to the effect of polymer cross-linking on these properties. It was revealed that the system possessed a pronounced shear-thinning behavior accompanied by a viscosity drop of 4–5 orders of magnitude. The polymer cross-links enhanced the shear-thinning properties and accelerated the viscosity recovery at rest so that the system could regain 96% of viscosity in only 18 s. Increasing the cross-linking of the soft network also enhanced the storage modulus of the nanocomposite system by up to 2 kPa. Through SAXS data, it was shown that at cross-linking, the junction zones consisting of fragments of two laterally aligned polymer chains were formed, which should have provided additional strength to the hydrogel. At the same time, the cross-linking of the soft network only slightly affected the yield stress, which seemed to be mainly determined by the rigid percolation network of nanotubes and reached 327 Pa. These properties make the alginate/halloysite hydrogels very promising for 3D printing, in particular, for biomedical purposes taking into account the natural origin, low toxicity, and good biocompatibility of both components.

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Wound healing is a complex set of body responses to damaged tissues, which manifests itself through local destructive-inflammatory changes and general reactions. There are numerous coatings used currently in clinical practice to treat wounds. These coatings serve to develop a wet anti-bacterial environment, which is essential to facilitate the healing process. This work focuses on studying multifunctional coatings, which are based on chitosan, a biocompatible polymer featuring wound-healing properties. The distinctive feature to be found in chitosan fibers is their density and the orientation of pores. The coatings within this study were tested on scalped full-layer skin wounds of male Wistar-Kyoto rats and male rabbits. The sample with a dense structure and low biological resorption was found to be effective in performing the function of a framework, as well as in ensuring proper drainage at the affected area. This is important when treating purulent wounds. The experimental sample with a high degree of adhesion and a shorter biodegradation life can be recommended for treating wounds with no purulent-inflammatory issues, for granulating wounds, as well as a drug carrier-matrix. The studied wound coatings have revealed their medical efficiency at the preclinical stage (in vivo). Using wound coatings with specified structural and functional features would allow making a reasonable choice when selecting a coating depending on the stage of wound healing course.

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