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End date: 2023 × End date: 2022 × Start date: 2022 × WGL Institute: DWI ×

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Now showing 1 - 6 of 6
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    Optical and chemical control of the wettability of nanoporous photoswitchable films
    (Cambridge : Royal Society of Chemistry, 2022) Zhang, Zejun; Chen, Donghui; Mutruc, Dragos; Hecht, Stefan; Heinke, Lars
    Wettability is a central surface property of functional thin films. Here, we present a nanoporous film made of an azobenzene-containing metal-organic framework material where the wettability is controlled by photoswitching of the fluorinated azobenzene moieties and by reversible incorporation of guest molecules with different polarities in the pores. Using both, the optical and the chemical stimuli, the water contact angle was modified over a wide range, from 23° to 97°.
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    Mechanoresponsive diselenide-crosslinked microgels with programmed ultrasound-triggered degradation and radical scavenging ability for protein protection
    (Cambridge : RSC Publishing, 2022) Kharandiuk, Tetiana; Tan, Kok Hui; Xu, Wenjing; Weitenhagen, Fabian; Braun, Susanne; Göstl, Robert; Pich, Andrij
    In the context of controlled delivery and release, proteins constitute a delicate class of cargo requiring advanced delivery platforms and protection. We here show that mechanoresponsive diselenide-crosslinked microgels undergo controlled ultrasound-triggered degradation in aqueous solution for the release of proteins. Simultaneously, the proteins are protected from chemical and conformational damage by the microgels, which disintegrate to water-soluble polymer chains upon sonication. The degradation process is controlled by the amount of diselenide crosslinks, the temperature, and the sonication amplitude. We demonstrate that the ultrasound-mediated cleavage of diselenide bonds in these microgels facilitates the release and activates latent functionality preventing the oxidation and denaturation of the encapsulated proteins (cytochrome C and myoglobin) opening new application possibilities in the targeted delivery of biomacromolecules.
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    Nanomedicine‐boosting icaritin-based immunotherapy of advanced hepatocellular carcinoma
    (London : BioMed Central, 2022) Lu, Yi; Gao, Yue; Yang, Huan; Hu, Yong; Li, Xin
    Traditional treatments for advanced hepatocellular carcinoma (HCC), such as surgical resection, transplantation, radiofrequency ablation, and chemotherapy are unsatisfactory, and therefore the exploration of powerful therapeutic strategies is urgently needed. Immunotherapy has emerged as a promising strategy for advanced HCC treatment due to its minimal side effects and long-lasting therapeutic memory effects. Recent studies have demonstrated that icaritin could serve as an immunomodulator for effective immunotherapy of advanced HCC. Encouragingly, in 2022, icaritin soft capsules were approved by the National Medical Products Administration (NMPA) of China for the immunotherapy of advanced HCC. However, the therapeutic efficacy of icaritin in clinical practice is impaired by its poor bioavailability and unfavorable in vivo delivery efficiency. Recently, functionalized drug delivery systems including stimuli-responsive nanocarriers, cell membrane-coated nanocarriers, and living cell-nanocarrier systems have been designed to overcome the shortcomings of drugs, including the low bioavailability and limited delivery efficiency as well as side effects. Taken together, the development of icaritin-based nanomedicines is expected to further improve the immunotherapy of advanced HCC. Herein, we compared the different preparation methods for icaritin, interpreted the HCC immune microenvironment and the mechanisms underlying icaritin for treatment of advanced HCC, and discussed both the design of icaritin-based nanomedicines with high icaritin loading and the latest progress in icaritin-based nanomedicines for advanced HCC immunotherapy. Finally, the prospects to promote further clinical translation of icaritin-based nanomedicines for the immunotherapy of advanced HCC were proposed.
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    Solvent effects on catalytic activity and selectivity in amine-catalyzed D-fructose isomerization
    (Amsterdam [u.a.] : Elsevier, 2022) Drabo, Peter; Fischer, Matthias; Emondts, Meike; Hamm, Jegor; Engelke, Mats; Simonis, Marc; Qi, Long; Scott, Susannah L.; Palkovits, Regina; Delidovich, Irina
    Rational catalyst design and optimal solvent selection are key to advancing biorefining. Here, we explored the organocatalytic isomerization of D-fructose to a valuable rare monosaccharide, D-allulose, as a function of solvent. The isomerization of D-fructose to D-allulose competes with its isomerization to D-glucose and sugar degradation. In both water and DMF, the catalytic activity of amines towards D-fructose is correlated with their basicity. Solvents impact the selectivity significantly by altering the tautomeric distribution of D-fructose. Our results suggest that the furanose tautomer of D-fructose is isomerized to D-allulose, and the fractional abundance of this tautomer increases as follows: water < MeOH < DMF ≈ DMSO. Reaction rates are also higher in aprotic than in protic solvents. The best D-allulose yield, 14 %, was obtained in DMF with 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as the catalyst. The reaction kinetics and mechanism were explored using operando NMR spectroscopy.
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    Engineered living hydrogels for robust biocatalysis in pure organic solvents
    (Maryland Heights, MO : Cell Press, 2022) Gao, Liang; Feng, Lilin; Sauer, Daniel F.; Wittwer, Malte; Hu, Yong; Schiffels, Johannes; Li, Xin
    Engineered living hydrogels that can protect cells from harsh environments have achieved preliminary successes in biomedicine and environmental remediation. However, their biocatalytic applications in pure organic solvents have not been explored. Here, living hydrogels were engineered by integrating genetically modified Escherichia coli cells into alginate hydrogels for robust biocatalysis in pure organic solvents. The biocompatible hydrogels could not only support cell growth and diminish cell escape but could also act as protective matrices to improve organic solvent tolerance, thereby prolonging catalytic activity of whole-cell biocatalysts. Moreover, the influence of hydrogel microenvironments on biocatalytic efficiency was thoroughly investigated. Importantly, the versatility of engineered living hydrogels paves the way to achieve robust biocatalytic efficiency in a variety of pure organic co-solvents. Overall, we are able to engineer living hydrogels for regio-selective synthesis in pure organic solvents, which may be particularly useful for the innovation of living hydrogels in biocatalysis.
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    From In Vitro to Perioperative Vascular Tissue Engineering: Shortening Production Time by Traceable Textile-Reinforcement
    (Heidelberg : Springer, 2022) Mohapatra, Saurav Ranjan; Rama, Elena; Melcher, Christoph; Call, Tobias; Al Enezy-Ulbrich, Miriam Aischa; Pich, Andrij; Apel, Christian; Kiessling, Fabian; Jockenhoevel, Stefan
    Background: The production of tissue-engineered vascular graft (TEVG) usually involves a prolonged bioreactor cultivation period of up to several weeks to achieve maturation of extracellular matrix and sufficient mechanical strength. Therefore, we aimed to substantially shorten this conditioning time by combining a TEVG textile scaffold with a recently developed copolymer reinforced fibrin gel as a cell carrier. We further implemented our grafts with magnetic resonance imaging (MRI) contrast agents to allow the in-vitro monitoring of the TEVG’s remodeling process. Methods: Biodegradable polylactic-co-glycolic acid (PLGA) was electrospun onto a non-degradable polyvinylidene fluoride scaffold and molded along with copolymer-reinforced fibrin hydrogel and human arterial cells. Mechanical tests on the TEVGs were performed both instantly after molding and 4 days of bioreactor conditioning. The non-invasive in vitro monitoring of the PLGA degradation and the novel imaging of fluorinated thermoplastic polyurethane (19F-TPU) were performed using 7T MRI. Results: After 4 days of close loop bioreactor conditioning, 617 ± 85 mmHg of burst pressure was achieved, and advanced maturation of extracellular matrix (ECM) was observed by immunohistology, especially in regards to collagen and smooth muscle actin. The suture retention strength (2.24 ± 0.3 N) and axial tensile strength (2.45 ± 0.58 MPa) of the TEVGs achieved higher values than the native arteries used as control. The contrast agents labeling of the TEVGs allowed the monitorability of the PLGA degradation and enabled the visibility of the non-degradable textile component. Conclusion: Here, we present a concept for a novel textile-reinforced TEVG, which is successfully produced in 4 days of bioreactor conditioning, characterized by increased ECM maturation and sufficient mechanical strength. Additionally, the combination of our approach with non-invasive imaging provides further insights into TEVG’s clinical application.