Materials Science

The immense application potential of amphiphilic protein-polymer conjugates remains largely unexplored, as established “grafting from” synthetic protocols involve time-consuming, harsh and disruptive deoxygenation methods, while “grafting to” approaches result in low yields. Here we report an oxygen tolerant, photoinduced CRP approach which readily affords quantitative yields of protein-polymer conjugates within 2 h, avoiding damage to the secondary structure of the protein and providing easily accessible means to produce biomacromolecular assemblies. Importantly, our methodology is compatible with multiple proteins (e.g. BSA, HSA, GOx, beta-galactosidase) and monomer classes including acrylates, methacrylates, styrenics and acrylamides. The polymerizations are conveniently conducted in plastic syringes and in the absence of any additives or external deoxygenation procedures using low-organic content media and ppm levels of copper. The robustness of the protocol is further exemplifi...

The authors acknowledge the Swiss National Science Foundation (200020-113804/1) for financial support. We thank D. Gerard for the synthesis of the initiator, Dr. C. Bauer and J. Bosset at the Bioimaging Platform of the University of Geneva for their assistance with microscopy, and D.-H. Tran and the SVSMS Mass Spectrometry Core Facility of the University of Geneva for the MALDI-TOF MS measurements. Supporting information (including full descriptions of all experiments conducted in this study) for this article is available on the WWW under http://dx.

Enzyme in Vesikeln kˆnnen die Umsetzung von Substraten katalysieren, die die Vesikelmembran durchdringen. Das Titelbild zeigt eine Vesikel, die aus einem Stab-Kn‰uel-Diblockcopolymer gebildet wird und Lipase B enth‰lt. Die Thiophen-Einheiten am Polymer lassen sich durch Zugabe eines Metallkomplexes polymerisieren. Dies kˆnnte den Weg zu leitf‰higen Vesikelmembranen weisen und neue Mˆglichkeiten auf dem Gebiet der Nanoreaktoren erˆffnen. Lesen Sie mehr hier¸ber in der Zuschrift von A. E. Rowan und R. J. M. Nolte et al. auf S. 796 ff.

During the last decades, numerous studies have focused on combining the unique catalytic/functional properties and structural characteristics of proteins and enzymes with those of synthetic molecules and macromolecules. The aim of such multidisciplinary studies is to improve the properties of the natural component, combine them with those of the synthetic, and create novel biomaterials in the nanometer scale. The specific coupling of polymers onto the protein structures has proved to be one of the most straightforward and applicable approaches in that sense. In this article, we focus on the synthetic pathways that have or can be utilized to specifically couple proteins to polymers. The different categories of welldefined protein-polymer conjugates and the effect of the polymer on the protein function are discussed. Studies have shown that the specific conjugation of a synthetic polymer to a protein conveys its physico-chemical properties and, therefore, modifies the biodistribution and solubility of the protein, making it in certain cases soluble and active in organic solvents. An overview of the applications derived from such bioconjugates in the pharmaceutical industry, biocatalysis, and supramolecular nanobiotechnology is presented at the final part of the article.

Investigation of the stereochemistry of the hydride transfer in reactions catalyzed by the recently isolated NAD +-linked alcohol dehydrogenase from the Antarctic psychrophile Moraxella sp. TAE123 was accomplished by using 1H NMR spectroscopy of the deuterated coenzyme. It was found that this new psychrophilic enzyme is a type A dehydrogenase. MoraxeIla sp. ADH reduces stereospecifically 2butanone to produce (S)-2-butanol.

By incorporating an ester-containing substrate in a selfassembled alignment layer for liquid crystal cells, the presence of a lipase (CALB) can be directly detected through its enzymatic action on the alignment layer, without the need for fluorescent labelling or enzyme assays.

fax: +31 (0)24 365 29 29. off φ from the trajectory is obtained even when the bin size used to define the trajectory, dt, is much larger than the parameter τ. This holds true as long as the first moment of the WT-PDF is much larger than dt. Our results validate the results in an earlier study of the activity of single Lipase B molecules and disprove recent related critique.

A novel, generic method for the synthesis of families of tri-block protein-polymer giant amphiphiles was designed and developed. We have synthesized a hydrophilic a-maleimido poly-1alkyne with M n = 9.5 kDa (1 H-NMR) and narrow PDi (1.15 as measured by SEC) via ATRP (Atom Transfer Radical Polymerization). This polymer was succesfully coupled to BSA to afford a hydrophilic multifunctional bioconjugate which was isolated using protein purification techniques and fully characterized. Following the post-functionalization approach, we introduced hydrophobicity to the resulting hydrophilic biohybrid by a straightforward, high yield ''click''-chemistry cycloaddition step. The resulting tri-block protein-polymer amphiphiles were isolated and showed interesting aggregation patterns (TEM, confocal microscopy).

is currently a Ph.D.-student at the University of Geneva, studying in the field of amphiphilic polymer-protein conjugates toward the formation of well-defined functional nanoassemblies. After studying chemistry and obtaining a master degree in molecular chemistry at the Université de Rennes (France), he joined the group of Dr. Velonia in 2005 for a Ph.D. position. Kelly Velonia joined the faculty of the Department of Materials Science and Technology of the University of Crete in 2008, after 4 years in the Department of Organic Chemistry of the University of Geneva. She has been involved in the past in mechanistic studies of enzymatic reactions, the development of protein-polymer conjugates and nanoreactors and single molecule photophysics and is now focusing in the development of well-defined, multifunctional biohybrid nanomaterials for application in polymer, material and life sciences and nanotechnology. In 2002, she received the Europa Medal and Prize Award. Scheme 1. General scheme of ''click'' chemistry cycloaddition reactions.

Single-molecule techniques offer a unique tool for studying the dynamical behavior of individual molecules and provide the possibility to construct distributions from individual events rather than from a signal stemming from an ensemble of molecules. In biological systems, known for their complexity, these techniques make it possible to gain insights into the detailed spectrum of molecular conformational changes and activities. Here, we report on the direct observation of a single lipase-catalyzed reaction for extended periods of time (hours), by using confocal fluorescence microscopy. When adding a profluorescent substrate, the monitored enzymatic activity appears as a trajectory of ''on-state'' and ''off-state'' events. The waiting time probability density function of the off state and the state-correlation function fit stretched exponentials, independent of the substrate concentration in a certain range. The data analysis unravels oscillations in the logarithmic derivative of the off-state waiting time probability density function and correlations between off-state events. These findings imply that the fluctuating enzyme model, which involves a spectrum of enzymatic conformations that interconvert on the time scale of the catalytic activity, best describes the observed enzymatic activity. Based on this model, values for the coupling and reaction rates are extracted.

Racemic trans-4,5-dimethylhydrofuran-2(3H)-one was synthesised from 5-methyl-furan-2(3H)-one, (a-angelica lactone). The key reaction in the synthesis was the 1,4-conjugate addition of an organocuprate to 5-methylfuran-2(5H)-one (b-angelica lactone). Different types of organocuprates were tested with the highest anti:syn ratio of 99.4:0.6 being obtained by the use of a Gilman organocuprate reagent. The enantioselective acylation of racemic 3-methyl-pentan-1,4-diol, catalysed by a variety of lipases in organic media, was investigated. The highest enantioselectivity (E >400) was obtained when Novozyme 435 was used as the catalyst at a water activity of a w $ 0. Thus, both enantiomers, (3S,4R)-and (3R,4S)-3-methyl-pentan-1,4-diol, were obtained in very high diastereomeric (>99% de) and enantiomeric purities (>99.8% and >97.4% ee, respectively).

The aim of this study was to address one of the major challenges of the actual era of nanomedicine namely, the bioavailability of poorly water soluble drugs such as Silymarin. We developed new, biodegradable, and biocompatible nanosized shuttles for Silymarin targeted delivery in colon-cancer cells. The design of these 100 nm sized carrier nanoparticles was based on natural polymers and their biological properties such as cellular uptake potential, cytotoxicity and 3D penetrability were tested using a colon cancer cell line (HT-29) as the in vitro culture model. Comparative scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements demonstrated that the Silymarin loaded Poly(3-HydroxyButyrate-co-3-HydroxyValerate) (PHBHV) nanocarriers significantly decreased HT-29 cells viability after 6 and 24 h of treatment. Moreover, in vivo-like toxicity studies on multicellular tumor spheroids showed that the Silymarin loaded PHBHV nanocarriers are able to penetrate 3D mi...

Ability to deliver drugs into the cell nuclei can significantly increase the efficacy of cancer therapies, in particular in the case of multidrug-resistant cancer Results: Polymer nanocarriers based on amphiphilic thiooctadecyl-terminated poly-N-vinyl-2-pyrrolidone were produced and loaded with a model hydrophobic drug, curcumin. Two commonly used loading approaches - emulsification and ultrasonic dispersion - were found to lead to two different size distributions with distinctively different biological effect. While nanocarriers produced via the emulsion method penetrated cells by dynamin-dependent endocytic mechanisms, sub-100 nm dispersion-produced nanocarriers were capable of crossing the membranes via biologically independent mechanisms. This finding opens an intriguing possibility of intranuclear delivery by merely tailoring the size of polymeric carriers, thus promising a new approach for cancer therapies.

As am ethod for overcoming the challenge of rigorous deoxygenation in copper-mediated controlled radical polymerization processes [e.g., atom-transfer radical polymerization (ATRP)],r eported here is as imple Cu 0-RDRP (RDRP = reversible deactivation radical polymerization) system in the absence of external additives (e.g.,r educing agents,enzymes etc.). By simply adjusting the headspace of the reaction vessel, aw ide range of monomers,n amely acrylates, methacrylates,acrylamides,and styrene,can be polymerizedin ac ontrolled manner to yield polymers with low dispersities, near-quantitative conversions,a nd high end-group fidelity. Significantly,t his approach is scalable (ca. 125 g), tolerant to elevated temperatures,c ompatible with both organic and aqueous media, and does not rely on external stimuli which may limit the monomer pool. The robustness and versatility of this methodology is further demonstrated by the applicability to other copper-mediated techniques,i ncluding conventional ATRP and light-mediated approaches. Figure 1. Oxygen-tolerant approaches for RDRP. [

The degree of purity of materials recovered from municipal solid waste (MSW) depends mainly on the objective: the intended use of the recovered material and the cost to recover this material in its pure form, determined by the intensity of the effort and the technology involved. The Bio-waste to Bio-plastic (B2B) Project aims to develop an integrated separation process at the bio-waste source, focusing on Hospitality Units. The quality of the collected bio-waste will be upgraded by removing foreign bodies or even specific categories of food waste, or by adding bio-waste from other, more specialized, sources (e.g. bakery residues) to produce compostable bio-plastics through an optimal synthesis process. Compostable bio-plastics are high added value products, which justify an increase in the cost of the preceding processes. After examining the possibility of further source separation and its results, B2B will study the optimal collection and transport system which decisively affects m...

Food waste is a stream with multiple social, economic, and environmental implications, generated throughout all the life cycle stages of food. Among these stages, in developed and top touristic destination countries such as Greece, the role of the hospitality sector (i.e., restaurants, hotels, catering, etc.) in food waste generation is particularly significant. Against this background, the A2UFood project introduces a holistic management scheme in the municipality of Heraklion (Crete, Greece), in which all aspects of reduction, reuse, and recycling of food waste are included. The project seeks to implement the circular economy concept into daily practice, through a series of actions which preserve natural resources, support local communities, and create new value chains. More specifically, the holistic management scheme of the A2UFood project progresses towards three innovative directions: (i) Surplus food of high quality, from hotels and restaurants, will be redirected to people i...