Bacterial cellulose (BC) is a nanocellulose form produced by some nonpathogenic bacteria. BC presents unique physical, chemical, and biological properties that make it a very versatile material and has found application in several fields, namely in food industry, cosmetics, and biomedicine. This review overviews the latest state‐of‐the‐art usage of BC on three important areas of the biomedical field, namely delivery systems, wound dressing and healing materials, and tissue engineering for regenerative medicine. BC will be reviewed as a promising biopolymer for the design and development of innovative materials for the mentioned applications. Overall, BC is shown to be an effective and versatile carrier for delivery systems, a safe and multicustomizable patch or graft for wound dressing and healing applications, and a material that can be further tuned to better adjust for each tissue engineering application, by using different methods.
Polyoxometalates are an emerging class of molecular clusters, with well‐defined structures and chemical compositions that are produced through simple, low‐cost, and highly reproducible methods. In particular, the wheel‐shaped cluster {Mo154} is a promising photothermal agent due to its intervalence charge transfer transitions. However, its toxicity hinders its systemic administration, being the development of a localized delivery system still incipient. Herein, an injectable and self‐healing hydrogel of easy preparation and administration is developed, incorporating both {Mo154} and doxorubicin for synergistic photothermal and chemotherapy applications. The hydrogel is composed of benzylaldehyde functionalized polyethylene glycol, poly(N‐isopropylacrylamide) functionalized chitosan and {Mo154}. The gelation occurs within 60 s at room temperature, and the dual crosslinking by Schiff base and electrostatic interactions generates a dynamic network, which enables self‐healing after injection. Moreover, the hydrogel delivers chemotherapeutic drugs, with a release triggered by dual near infra‐red (NIR) radiation and pH changes. This stimuli‐responsive release system along with the photothermal conversion ability of the hydrogel allows the simultaneous combination of photothermal and chemotherapy. This synergic system efficiently ablates the cancer tumor in vivo with no systemic toxicity. Overall, this work paves the way for the development of novel {Mo154}‐based systems, incorporated in self‐healing and injectable hydrogels for dual chemo‐photothermal therapy.
Many applications involving ionic liquids (ILs) require the knowledge of their interfacial behaviour, such as wettability and adhesion. In this context, herein, two approaches were combined aiming at understanding the impact of the IL chemical structures on their wettability on both polar and non-polar surfaces, namely: (i) the experimental determination of the contact angles of a broad range of ILs (covering a wide number of anions of variable polarity, cations, and cation alkyl side chain lengths) on polar and non-polar solid substrates (glass, Al-plate, and poly-(tetrafluoroethylene) (PTFE)); and (ii) the correlation of the experimental contact angles with the cation-anion pair interaction energies generated by the Conductor-like Screening Model for Real Solvents (COSMO-RS). The combined results reveal that the hydrogen-bond basicity of ILs, and thus the IL anion, plays a major role through their wettability on both polar and non-polar surfaces. The increase of the IL hydrogen-bond accepting ability leads to an improved wettability of more polar surfaces (lower contact angles) while the opposite trend is observed on non-polar surfaces. The cation nature and alkyl side chain lengths have however a smaller impact on the wetting ability of ILs. Linear correlations were found between the experimental contact angles and the cation-anion hydrogen-bonding and cation ring energies, estimated using COSMO-RS, suggesting that these features primarily control the wetting ability of ILs. Furthermore, twodescriptor correlations are proposed here to predict the contact angles of a wide variety of ILs on glass, Al-plate, and PTFE surfaces. A new extended list is provided for the contact angles of ILs on three surfaces, which can be used as a priori information to choose appropriate ILs before a given application.
The electrons go in two by two: Scanning tunneling microscopy (STM)/spectroscopy (STS), shows the Mo154 giant wheel cluster to have a unique localization of states within each of the 14 identical compartments forming its necklace‐type structure (see picture). Each compartment contains two delocalized electrons. These states make the system different from conventional quantum dots that have completely free electrons or excitonic states.
Reaction of the cyclic {P(8)W(48)} polyoxotungstate host with sodium molybdate in solution in the presence of a reducing agent leads to the formation and stabilization of unprecedented neutral {Mo(V)(4)O(10)(H(2)O)(3)} aggregates with handle function, thereby proving the potential of the present host for performing future interesting studies related to mixed-valence type chemistry under confined conditions.
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