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Wang X.,CNRS Charles Coulomb Laboratory | In M.,CNRS Charles Coulomb Laboratory | Blanc C.,CNRS Charles Coulomb Laboratory | Nobili M.,CNRS Charles Coulomb Laboratory | And 2 more authors.
Soft Matter | Year: 2015

We have investigated the active motion of self-propelled colloids confined at the air-water interface and explored the possibility of enhancing the directional motion of self-propelled Janus colloids by slowing down their rotational diffusion. The two dimensional motion of micron-sized silica-platinum Janus colloids has been experimentally measured by particle tracking video-microscopy at increasing concentrations of the catalytic fuel, i.e. H2O2. Compared to the motion in the bulk, a dramatic enhancement of both the persistence length of trajectories and the speed has been observed. The interplay of colloid self-propulsion, due to an asymmetric catalytic reaction occurring on the colloid, surface properties and interfacial frictions controls the enhancement of the directional movement. The slowing down of the rotational diffusion at the interface, also measured experimentally, plays a pivotal role in the control and enhancement of active motion. © The Royal Society of Chemistry.


Lulsdorf N.,Dwi Leibniz Institute For Interaktive Materialien | Pitzler C.,RWTH Aachen | Biggel M.,RWTH Aachen | Martinez R.,EW Nutrition GmbH | And 3 more authors.
Chemical Communications | Year: 2015

A high throughput whole cell flow cytometer screening toolbox was developed and validated by identifying improved variants (1.3-7-fold) for three hydrolases (esterase, lipase, cellulase). The screening principle is based on coupled enzymatic reaction using glucose derivatives which yield upon hydrolysis a fluorescent-hydrogel-layer on the surface of E. coli cells. © The Royal Society of Chemistry 2015.


Pitzler C.,RWTH Aachen | Wirtz G.,RWTH Aachen | Vojcic L.,RWTH Aachen | Hiltl S.,Dwi Leibniz Institute For Interaktive Materialien | And 4 more authors.
Chemistry and Biology | Year: 2014

Screening throughput is a key in directed evolution experiments and enzyme discovery. Here, we describe a high-throughput screening platform based on a coupled reaction of glucose oxidase and a hydrolase (Yersinia mollaretii phytase [YmPh]). The coupled reaction produces hydroxyl radicals through Fenton's reaction, acting as initiator of poly(ethyleneglycol)-acrylate-based polymerization incorporating a fluorescent monomer. As a consequence, a fluorescent hydrogel is formed around Escherichia coli cells expressing active YmPh. We achieve five times enrichment of active cell population through flow cytometry analysis and sorting of mixed populations. Finally, we validate the performance of the fluorescent polymer shell (fur-shell) technology by directed phytase evolution that yielded improved variants starting from a library containing 107 phytase variants. Thus, fur-shell technology represents a rapid and nonlaborious way of identifying the most active variants from vast populations, as well as a platform for generation of polymer-hybrid cells for biobased interactive materials. © 2014 Elsevier Ltd.


Dhoke G.V.,RWTH Aachen | Ensari Y.,RWTH Aachen | Davari M.D.,RWTH Aachen | Ruff A.J.,RWTH Aachen | And 3 more authors.
Journal of Chemical Information and Modeling | Year: 2016

Zinc-dependent medium chain reductase from Candida parapsilosis can be used in the reduction of carbonyl compounds to pharmacologically important chiral secondary alcohols. To date, the nomenclature of cpADH5 is differing (CPCR2/RCR/SADH) in the literature, and its natural substrate is not known. In this study, we utilized a substrate docking based virtual screening method combined with KEGG, MetaCyc pathway, and Candida genome databases search for the discovery of natural substrates of cpADH5. The virtual screening of 7834 carbonyl compounds from the ZINC database provided 94 aldehydes or methyl/ethyl ketones as putative carbonyl substrates. Out of which, 52 carbonyl substrates of cpADH5 with catalytically active docking pose were identified by employing mechanism based substrate docking protocol. Comparison of the virtual screening results with KEGG, MetaCyc database search, and Candida genome pathway analysis suggest that cpADH5 might be involved in the Ehrlich pathway (reduction of fusel aldehydes in leucine, isoleucine, and valine degradation). Our QM/MM calculations and experimental activity measurements affirmed that butyraldehyde substrates are the potential natural substrates of cpADH5, suggesting a carbonyl reductase role for this enzyme in butyraldehyde reduction in aliphatic amino acid degradation pathways. Phylogenetic tree analysis of known ADHs from Candida albicans shows that cpADH5 is close to caADH5. We therefore propose, according to the experimental substrate identification and sequence similarity, the common name butyraldehyde dehydrogenase cpADH5 for Candida parapsilosis CPCR2/RCR/SADH. © 2016 American Chemical Society.


Artz J.,RWTH Aachen | Mallmann S.,Dwi Leibniz Institute For Interaktive Materialien | Palkovits R.,RWTH Aachen
ChemSusChem | Year: 2015

The selective aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran has been performed under mild conditions at 80 8C and 20 bar of synthetic air in methyl t-butyl ether. Ru clusters supported on covalent triazine frameworks (CTFs) allowed excellent selectivity and superior catalytic activity compared to other support materials such as activated carbon, γ-Al2O3, hydrotalcite, or MgO. CTFs with varying pore size, specific surface area, and N content could be prepared from different monomers. The structural properties of the CTF materials influence the catalytic activity of Ru/CTF significantly in the aerobic oxidation of HMF, which emphasizes the superior activity of mesoporous CTFs. Recycling of the catalysts is challenging, but promising methods to maintain high catalytic activity were developed that facilitate only minor deactivation in five consecutive recycling experiments. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Tigges T.,Dwi Leibniz Institute For Interaktive Materialien | Hoenders D.,Dwi Leibniz Institute For Interaktive Materialien | Walther A.,Dwi Leibniz Institute For Interaktive Materialien
Small | Year: 2015

Patchy particles are next generation colloidal building blocks for self-assembly and find further use as (bio) sensors. Progress in this direction crucially depends on developing straightforward preparation pathways able to provide patchy particles with highest uniformity and integrating precise, orthogonal, and spatially localized functionalizations to mediate interaction patterns. This continues to be one of the great challenges in colloid science. Herein, a method is shown utilizing functionalized random and block copolymers as microcontact printing inks to prepare patchy particles with outstanding control over patch size and quality. The polymeric nature and tight covalent attachment of the ink prevents flow of the ink over the particle during printing. This minimizes patch broadening and yields very small and extremely uniform patches, which is especially challenging for particle sizes below 10 μm. Click-type (amine/active ester, alkyne/azide, biotin/avidin) reactions can be performed selectively on the patch or on the particle body, rendering the particles interesting for application in imaging, biomolecular detection, and as advanced precision colloid-based building blocks. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Fajzulin I.,Dwi Leibniz Institute For Interaktive Materialien | Zhu X.,Dwi Leibniz Institute For Interaktive Materialien | Moller M.,Dwi Leibniz Institute For Interaktive Materialien
Journal of Coatings Technology Research | Year: 2015

Inorganic nanoparticles with UV-absorbing properties are an important class of UV filters. They can be used in various applications and in a variety of forms, including suspensions, nanocomposites, and solid thin films. In this review, an overview of the synthetic methods and their respective products is given for the most popular UV-absorbing nanomaterials, including zinc oxide, titanium dioxide, cerium dioxide and ferrous oxides, and oxyhydroxides. © 2015, American Coatings Association.


PubMed | Dwi Leibniz Institute For Interaktive Materialien
Type: Published Erratum | Journal: Chemical communications (Cambridge, England) | Year: 2015

Correction for A flow cytometer-based whole cell screening toolbox for directed hydrolase evolution through fluorescent hydrogels by Nina Llsdorf et al., Chem. Commun., 2015, 51, 8679-8682.


PubMed | Dwi Leibniz Institute For Interaktive Materialien
Type: Journal Article | Journal: Small (Weinheim an der Bergstrasse, Germany) | Year: 2015

Patchy particles are next generation colloidal building blocks for self-assembly and find further use as (bio) sensors. Progress in this direction crucially depends on developing straightforward preparation pathways able to provide patchy particles with highest uniformity and integrating precise, orthogonal, and spatially localized functionalizations to mediate interaction patterns. This continues to be one of the great challenges in colloid science. Herein, a method is shown utilizing functionalized random and block copolymers as microcontact printing inks to prepare patchy particles with outstanding control over patch size and quality. The polymeric nature and tight covalent attachment of the ink prevents flow of the ink over the particle during printing. This minimizes patch broadening and yields very small and extremely uniform patches, which is especially challenging for particle sizes below 10 m. Click-type (amine/active ester, alkyne/azide, biotin/avidin) reactions can be performed selectively on the patch or on the particle body, rendering the particles interesting for application in imaging, biomolecular detection, and as advanced precision colloid-based building blocks.


PubMed | Dwi Leibniz Institute For Interaktive Materialien
Type: Journal Article | Journal: Chemical communications (Cambridge, England) | Year: 2015

A high throughput whole cell flow cytometer screening toolbox was developed and validated by identifying improved variants (1.3-7-fold) for three hydrolases (esterase, lipase, cellulase). The screening principle is based on coupled enzymatic reaction using glucose derivatives which yield upon hydrolysis a fluorescent-hydrogel-layer on the surface of E. coli cells.

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