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Many hydrogel patches are developed to solve the pervasive and severe challenge of complex wound healing, while most of them still lack satisfactory controllability and comprehensive functionality. Herein, inspired by multiple creatures, including octopuses and snails, a novel muti-functional hydrogel patch is presented with controlled adhesion, antibacterial, drug release features, and multiple monitoring functions for intelligent wound healing management. The patch with micro suction-cup actuator array and a tensile backing layer is composed of tannin grafted gelatin, Ag-tannin nanoparticles, polyacrylamide (PAAm) and poly(N-isopropylacrylamide) (PNIPAm). In virtue of the photothermal gel-sol transition of tannin grafted gelatin and Ag-tannin nanoparticles, the patches exert a dual anti-microbial effect and temperature-sensitive snail mucus-like features. In addition, as the "suction-cups" consisting of thermal responsive PNIPAm can undergo a contract-relax transformation, the medical patches can adhere to the objects reversibly and responsively, and release their loaded vascular endothelial growth factor (VEGF) controllably for wound healing. More attractively, benefiting from their fatigue resistance, self-healing ability of the tensile double network hydrogel, and electrical conductivity of Ag-tannin nanoparticles, the proposed patches can report multiple wound physiology parameters sensitively and continuously. Thus, it is believed that this multi-bioinspired patch has immense potential for future wound healing management., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Enclosing the pesticide in a carrier and releasing it based on environmental stimuli is proved to be a viable strategy for addressing pesticide losses and mitigating environmental contamination. Here, an interpenetrating network (IPN) composite hydrogels (OMt/Alg/PNIPAm) with light and temperature responses was prepared by the incorporation of clay material, organo-montmorillonite (OMt), via the free-radical polymerization of N-isopropyl acrylamide (PNIPAm) and its crosslinking as well as ionic crosslinking reaction of sodium alginate (SA) with FeCl 3. The structure of OMt/Alg/PNIPAm was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermos gravimetric analysis (TGA) and rheometer. The hydrophobic pesticide λ-cyhalothrin (LC) was encapsulated in OMt and subsequently incorporated into the IPN structure of the composite hydrogels, ensuring the desirable mechanical properties, encapsulation efficiency and sustained release performances of the composite hydrogels. In addition, with the rising of OMt content, the IPN composite hydrogels exhibited a decrease in their swelling capacity, transparency, and temperature sensitivity. The OMt/Alg/PNIPAm with 9.0% OMt content displayed the highest loading rate for pesticides at 82.06% and the lowest release rate of pesticides at 3.90%. Furthermore, the IPN composite hydrogels possessed the ability to regulate the amount of pesticide release based on the variations in temperature and ambient light conditions. The resultant IPN composite hydrogels took advantage of the temperature responsiveness of PNIPAm, the light sensitivity of Fe3+-alginate hydrogel, and the adsorption capability of OMt, possessing great potentials in enhancing the utilization efficiency of hydrophobic pesticides through the development of effective and eco-friendly pesticide formulations. [Display omitted] • The intelligent OMt/Alg/PNIPAm with light and temperature response were prepared via IPN method. • The chemical crosslinking of PNIPAm and ionic crosslinking of SA achieved IPN composite hydrogels. • OMt was used to improve the mechanical property and drug-loading rate of the OMt/Alg/PNIPAm. • The OMt/Alg/PNIPAm could regulate the pesticide release in response to environmental stimuli. • The OMt/Alg/PNIPAm could be preferably used as potential hydrophobic pesticide carriers. [ABSTRACT FROM AUTHOR]

Photo-induced multi-color fluorescent hydrogels based on CPMC, SPCOOH and DCF for optical information encryption and coding. [Display omitted] • We fabricate multi-color fluorescent hydrogels containing CPMC, SPCOOH and DCF. • Hydrogels prove various photo-response induced by light of different band. • Based on the effect of borax, hydrogels possess reversible cross-linking property. • We apply the hydrogels to optical information coding and encryption. In this study, we proposed a method to prepare multi-color fluorescent hydrogels with polyvinyl alcohol (PVA) as the cross-linking network and 7-(6-carboxylpentoxy)-4-methylcoumarin (CPMC), N-ethoxyhexanoate-3,3-dimethyl-6-nitro-indolinspiropyran (SPCOOH) and 2′,7′-dichlorofluorescein (DCF) were introduced to the system. Due to the hydroxyl group in PVA can form a reversible borate bond with borax, the hydrogel could be combined with each other through this chemical bond, thus hydrogels possess reversible cross-linking property and programmable property. The introduction of CPMC, SPCOOH and DCF into the hydrogel could give the hydrogel different photo-response properties. Under UV light irradiation, PVA-CPMC, PVA-CPMC/DCF, PVA-SPCOOH and PVA/DCF hydrogels could emit blue, cyan, pink purple and green fluorescence respectively. In addition, PVA/DCF and PVA-CPMC/DCF hydrogels could emit green fluorescence under 505 nm light irradiation. Based on the various properties of hydrogels, we respectively demonstrated the application of hydrogels in the fields of two-dimensional information encryption, three-dimensional information encryption, three-dimensional information coding and anti-counterfeiting, which can achieve the expected results. Therefore, multi-color fluorescent hydrogels may have potential applications in information encryption, information coding, flexible display and other fields. [ABSTRACT FROM AUTHOR]

[Display omitted] • A self-healing hydrogel consists of PAM, PAA, and PDMAEMA. • Mo 7 endows the hydrogel with photochromic property. • Coumarin derivative endows the hydrogel with fluorescence property. • The hydrogel can be used for optical information coding and encryption. In this study, we proposed programmable photo-responsive self-healing hydrogels containing polyacrylamide (PAM), polyacrylic acid (PAA), poly[2-(dimethylamino) ethyl methacrylate] (PDMAEMA), ammonium molybdate (Mo 7), and 7–2(acryloyl hydroxypropyl)-4-methyl-coumarin (AHPMC). Because of the electrostatic interaction of PAA and PDMAEMA, the hydrogel demonstrates good self-healing properties. Moreover, we introduced Mo 7 and coumarin derivative in the hydrogel, respectively, which endows the hydrogel photo-responsive properties. Under the control of UV light, PAM-AD/Mo 7 hydrogel with photochromic behavior could turn atrovirens, and PAM-AD/AC hydrogel with photoluminescent properties could emit blue fluorescence. In contrast, PAM-AD hydrogel possesses no photo-responsive behavior. Based on the self-healing and photo-responsive properties of the hydrogels, the three hydrogel blocks could be programmed and healed as a whole combination. In addition, we demonstrated the application of the hydrogel in optical information coding and encryption, which possesses good information coding and encryption effect. Therefore, the photo-responsive self-healing hydrogel may have potential applications in flexible information display and encryption fields. [ABSTRACT FROM AUTHOR]