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End date: 2024 × Start date: 2020 × End date: 2019 × Start date: 2011 × Has files: Yes × Version: publishedVersion × Subject: Polyethylene Glycols × WGL Institute: DWI ×

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    Polymer Brush-Functionalized Chitosan Hydrogels as Antifouling Implant Coatings
    (Columbus, Ohio : American Chemical Society, 2017) Buzzacchera, Irene; Vorobii, Mariia; Kostina, Nina Yu; de Los Santos Pereira, Andres; Riedel, Tomáš; Bruns, Michael; Ogieglo, Wojciech; Möller, Martin; Wilson, Christopher J.; Rodriguez-Emmenegger, Cesar
    Implantable sensor devices require coatings that efficiently interface with the tissue environment to mediate biochemical analysis. In this regard, bioinspired polymer hydrogels offer an attractive and abundant source of coating materials. However, upon implantation these materials generally elicit inflammation and the foreign body reaction as a consequence of protein fouling on their surface and concomitant poor hemocompatibility. In this report we investigate a strategy to endow chitosan hydrogel coatings with antifouling properties by the grafting of polymer brushes in a "grafting-from" approach. Chitosan coatings were functionalized with polymer brushes of oligo(ethylene glycol) methyl ether methacrylate and 2-hydroxyethyl methacrylate using photoinduced single electron transfer living radical polymerization and the surfaces were thoroughly characterized by XPS, AFM, water contact angle goniometry, and in situ ellipsometry. The antifouling properties of these new bioinspired hydrogel-brush coatings were investigated by surface plasmon resonance. The influence of the modifications to the chitosan on hemocompatibility was assessed by contacting the surfaces with platelets and leukocytes. The coatings were hydrophilic and reached a thickness of up to 180 nm within 30 min of polymerization. The functionalization of the surface with polymer brushes significantly reduced the protein fouling and eliminated platelet activation and leukocyte adhesion. This methodology offers a facile route to functionalizing implantable sensor systems with antifouling coatings that improve hemocompatibility and pave the way for enhanced device integration in tissue.
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    Microfluidic fabrication of polyethylene glycol microgel capsules with tailored properties for the delivery of biomolecules
    (Cambridge : RSC, 2017) Guerzoni, Luis P. B.; Bohl, Jan; Jans, Alexander; Rose, Jonas C.; Koehler, Jens; Kuehne, Alexander J. C.; De Laporte, Laura
    Microfluidic encapsulation platforms have great potential not only in pharmaceutical applications but also in the consumer products industry. Droplet-based microfluidics is increasingly used for the production of monodisperse polymer microcapsules for biomedical applications. In this work, a microfluidic technique is developed for the fabrication of monodisperse double emulsion droplets, where the shell is crosslinked into microgel capsules. A six-armed acrylated star-shaped poly(ethylene oxide-stat-propylene oxide) pre-polymer is used to form the microgel shell after a photo-initiated crosslinking reaction. The synthesized microgel capsules are hollow, enabling direct encapsulation of large amounts of multiple biomolecules with the inner aqueous phase completely engulfed inside the double emulsion droplets. The shell thickness and overall microgel sizes can be controlled via the flow rates. The morphology and size of the shells are characterized by cryo-SEM. The encapsulation and retention of 10 kDa FITC-dextran and its microgel degradation mediated release are monitored by fluorescence microscopy. © 2017 The Royal Society of Chemistry.
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    Synthetic 3D PEG-Anisogel Tailored with Fibronectin Fragments Induce Aligned Nerve Extension
    (Columbus, Ohio : American Chemical Society, 2019) Licht, Christopher; Rose, Jonas C.; Anarkoli, Abdolrahman Omidinia; Blondel, Delphine; Roccio, Marta; Haraszti, Tamás; Gehlen, David B.; Hubbell, Jeffrey A.; Lutolf, Matthias P.; De Laporte, Laura
    An enzymatically cross-linked polyethylene glycol (PEG)-based hydrogel was engineered to promote and align nerve cells in a three-dimensional manner. To render the injectable, otherwise bioinert, PEG-based material supportive for cell growth, its mechanical and biochemical properties were optimized. A recombinant fibronectin fragment (FNIII9*-10/12-14) was coupled to the PEG backbone during gelation to provide cell adhesive and growth factor binding domains in close vicinity. Compared to full-length fibronectin, FNIII9*-10/12-14 supports nerve growth at similar concentrations. In a 3D environment, only the ultrasoft 1 w/v% PEG hydrogels with a storage modulus of ∼10 Pa promoted neuronal growth. This gel was used to establish the first fully synthetic, injectable Anisogel by the addition of magnetically aligned microelements, such as rod-shaped microgels or short fibers. The Anisogel led to linear neurite extension and represents a large step in the direction of clinical translation with the opportunity to treat acute spinal cord injuries.