Institut für Chemie und Bioanalytik
Dauerhafte URI für die Sammlunghttps://irf.fhnw.ch/handle/11654/24
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Ergebnisse nach Hochschule und Institut
Publikation Dynamics of early skin formation of tiling mortars investigated by microscopy and diffuse reflectance infrared Fourier transformed spectroscopy(Elsevier, 03/2013) Bühler, Theodor; Zurbriggen, Roger; Pieles, Uwe; Huwiler, L.; Raso, RenzoA freshly applied mortar layer is exposed to the environment and forms a skin in the following minutes. Skinning changes significantly the surface properties and therefore limits application procedures. In the case of a tile adhesive, the skin that is formed before the tile is embedded can reduce resulting adhesion properties. Reflected light microscopy reveals that surface “lakes” disappear between 5 and 10 min after mortar application and DRIFTS (diffuse reflectance infrared Fourier transformed spectroscopy) indicates that films of organics and carbonates form simultaneously at the surface.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Stabilizing enzymes within polymersomes by coencapsulation of trehalose(American Chemical Society, 22.06.2020) Saxer, Sina; Pieles, Uwe; Dinu, Maria Valentina; Dinu, Ionel Adrian; Meier, Wolfgang; Bruns, Nico; Bruns, NicoEnzymes are essential biocatalysts and very attractive as therapeutics. However, their functionality is strictly related to their stability, which is significantly affected by the environmental changes occurring during their usage or long-term storage. Therefore, maintaining the activity of enzymes is essential when they are exposed to high temperature during usage or when they are stored for extended periods of time. Here, we stabilize and protect enzymes by coencapsulating them with trehalose into polymersomes. The anhydrobiotic disaccharide preserved up to about 81% of the enzyme’s original activity when laccase/trehalose-loaded nanoreactors were kept desiccated for 2 months at room temperature and 75% of its activity when heated at 50 °C for 3 weeks. Moreover, the applicability of laccase/trehalose-loaded nanoreactors as catalysts for bleaching of the textile dyes orange G, toluidine blue O, and indigo was proven. Our results demonstrate the advantages of coencapsulating trehalose within polymersomes to stabilize enzymes in dehydrated state for extended periods of time, preserving their activity even when heated to elevated temperature.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Mechanical characteristics of beta sheet-forming peptide hydrogels are dependent on peptide sequence, concentration and buffer composition(Royal Society, 03/2018) Koch, Franziska; König, Finja; Meyer, Nina; Gattlen, Jasmin; Pieles, Uwe; Peters, Kirsten; Kreikemeyer, Bernd; Mathes, Stephanie; Saxer, Sina; Müller, MichaelSelf-assembling peptide hydrogels can be modified regarding their biodegradability, their chemical and mechanical properties and their nanofibrillar structure. Thus, self-assembling peptide hydrogels might be suitable scaffolds for regenerative therapies and tissue engineering. Owing to the use of various peptide concentrations and buffer compositions, the self-assembling peptide hydrogels might be influenced regarding their mechanical characteristics. Therefore, the mechanical properties and stability of a set of self-assembling peptide hydrogels, consisting of 11 amino acids, made from four beta sheet self-assembling peptides in various peptide concentrations and buffer compositions were studied. The formed self-assembling peptide hydrogels exhibited stiffnesses ranging from 0.6 to 205 kPa. The hydrogel stiffness was mostly affected by peptide sequence followed by peptide concentration and buffer composition. All self-assembling peptide hydrogels examined provided a nanofibrillar network formation. A maximum self-assembling peptide hydrogel dissolution of 20% was observed for different buffer solutions after 7 days. The stability regarding enzymatic and bacterial digestion showed less degradation in comparison to the self-assembling peptide hydrogel dissolution rate in buffer. The tested set of self-assembling peptide hydrogels were able to form stable scaffolds and provided a broad spectrum of tissue-specific stiffnesses that are suitable for a regenerative therapy.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Amino acid composition of nanofibrillar self-assembling peptide hydrogels affects responses of periodontal tissue cells in vitro(Dove Medical Press, 10/2018) Koch, Franziska; Wolff, Anne; Mathes, Stephanie; Pieles, Uwe; Saxer, Sina; Kreikemeyer, Bernd; Peters, KirstenThe regeneration of tissue defects at the interface between soft and hard tissue, eg, in the periodontium, poses a challenge due to the divergent tissue requirements. A class of biomaterials that may support the regeneration at the soft-to-hard tissue interface are self-assembling peptides (SAPs), as their physicochemical and mechanical properties can be rationally designed to meet tissue requirements.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Biomimetic Remineralization of Carious Lesions by Self-Assembling Peptide(SAGE, 27.03.2017) Kind, Lucy; Stevanovic, Sabrina; Wuttig, Sina; Wimberger, Sandra; Hofer, Joëlle; Müller, Bert; Pieles, UweSelf-assembling β-sheet forming peptide P11-4 has shown potential in the treatment and prevention of dental caries by supporting tissue regeneration. It has previously been shown that application of monomeric P11-4 solution to early carious lesions can increase net mineral gain by forming de novo hydroxyapatite crystals. The hypothesis for the mode of action was that monomeric self-assembling peptide P11-4 diffuses into the subsurface lesion body and assembles therein into higher order fibrils, facilitating mineralization of the subsurface volume by mimicking the natural biomineralization of the tooth enamel.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Stimulus Dependent Flow through Polymer Modified Filtration Membranes(2016) Köser, Joachim; Pieles, Uwe06 - PräsentationPublikation Antibacterial Active Glass(25.02.2016) Köser, Joachim; Pieles, Uwe; Meier, Pascal; Widmer, A.06 - PräsentationPublikation Plasma-Etched Nanostructured Polycarbonate Surfaces for Reduced Adhesion of E.coli bacteria(30.06.2016) Grether, Yasmin; Waser, Marcus; Pieles, Uwe; Köser, JoachimPlasma-etching represents a facile approach to nanostructure polymer surfaces. Here we report on the antibacterial properties of plasma-structured polycarbonate (PC)surfaces. PC foils were structured with O2 plasma and incubated with E.coli. Metabolic activity of adhered live bacteria was quantified with resazurin metabolic indicator. Different incubation times under shaking/resting conditions diminished metabolic activity on structured versus unstructured PC, indicating reduced bacterial adhesion on structured surfaces. Furthermore chemical surface modifications increased metabolic activity on structured compared to unstructured surfaces. Further research on other polymers will be done to analyse the generality of these observations.06 - Präsentation