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Århus, Denmark

Larsen E.K.U.,University of Aarhus | Nielsen T.,INANO | Wittenborn T.,INANO | Rydtoft L.M.,Aarhus University Hospital | And 8 more authors.

Iron oxide nanoparticles have found widespread applications in different areas including cell separation, drug delivery and as contrast agents. Due to water insolubility and stability issues, nanoparticles utilized for biological applications require coatings such as the commonly employed polyethylene glycol (PEG). Despite its frequent use, the influence of PEG coatings on the physicochemical and biological properties of iron nanoparticles has hitherto not been studied in detail. To address this, we studied the effect of 333-20000 Da PEG coatings that resulted in larger hydrodynamic size, lower surface charge, longer circulation half-life, and lower uptake in macrophage cells when the particles were coated with high molecular weight (M w) PEG molecules. By use of magnetic resonance imaging, we show coating-dependent in vivo uptake in murine tumors with an optimal coating M w of 10000 Da. © 2012 The Royal Society of Chemistry. Source

Krogsgaard M.,INANO | Andersen A.,INANO | Birkedal H.,INANO
Chemical Communications

An inexpensive one-pot route to self-healing hydrogels with pH-tunable modulus is presented. Hydrogels were formed by reacting tannic acid, trivalent metal ions and polyallylamine. Below pH 8 the hydrogels were supramolecular while above, covalent cross-linking strengthened the hydrogels. From concentrated mixtures, threads were spun, acting as water sensitive mechanical locks. This journal is © the Partner Organisations 2014. Source

Krogsgaard M.,INANO | Nue V.,INANO | Birkedal H.,INANO
Chemistry - A European Journal

Improved understanding of the underwater attachment strategy of the blue mussels and other marine organisms has inspired researchers to find new routes to advanced materials. Mussels use polyphenols, such as the catechol-containing amino acid 3,4-dihydroxyphenylalanine (DOPA), to attach to surfaces. Catechols and their analogues can undergo both oxidative covalent cross-linking under alkaline conditions and take part in coordination chemistry. The former has resulted in the widespread use of polydopamine and related materials. The latter is emerging as a tool to make self-healing materials due to the reversible nature of coordination bonds. We review how mussel-inspired materials have been made with a focus on the less developed use of metal coordination and illustrate how this chemistry can be widely to make self-healing materials. Inspired by nature: The ability of blue mussels and other marine creatures to attach to surfaces underwater and to make advanced materials has gained increasing awareness and interest amongst chemists. The combination of catechols and coordination chemistry to yield self-healing materials is the most recent sprout on this growing tree and is the focus of this Minireview. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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