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Atherosclerosis is a leading cause of death worldwide. Antioxidant therapy has been considered a promising treatment modality for atherosclerosis, since reactive oxygen species (ROS) play a major role in the pathogenesis of atherosclerosis. We developed ROS-scavenging antioxidant nanoparticles (NPs) that can serve as an effective therapy for atherosclerosis. The newly developed novel antioxidant ROS-eliminating NPs were synthesized via reversible addition–fragmentation chain-transfer (RAFT) polymerization and act as a superoxide dismutase (SOD) mimetic agent. SOD is an anti-ROS enzyme which is difficult to use for passive delivery due to its low half-life and stability. Copolymers were synthesized using different feed ratios of 2,2,6,6-tetramethyl-4-piperidyl methacrylate (PMA) and glycidyl methacrylate (GMA) monomers and an anti-ROS nitroxyl radical polymer was prepared via oxidation. The copolymer was further conjugated with a 6-aminofluorescein via a oxirane ring opening reaction for intracellular delivery in RAW 264.7 cells. The synthesized copolymers were blended to create NPs (∼150 nm size) in aqueous medium and highly stable up to three weeks. The NPs were shown to be taken up by macrophages and to be cytocompatible even at high dose levels (500 μg mL−1). Finally, the nitroxide NPs has been shown to inhibit foam cell formation in macrophages by decreasing internalization of oxidized low-density lipoproteins.

Resonant microstrings show promise as a new analytical tool for thermal characterization of polymers with only few nanograms of sample. The detection of the glass transition temperature (Tg) of an amorphous poly(d,l-lactide) (PDLLA) and a semicrystalline poly(l-lactide) (PLLA) is investigated. The polymers are spray coated on one side of the resonating microstrings. The resonance frequency and quality factor (Q) are measured simultaneously as a function of temperature. Change in the resonance frequency reflects a change in static tensile stress, which yields information about the Young’s modulus of the polymer, and a change in Q reflects the change in damping of the polymer-coated string. The frequency response of the microstring is validated with an analytical model. From the frequency independent tensile stress change, static Tg values of 40.6 and 57.6 °C were measured for PDLLA and PLLA, respectively. The frequency-dependent damping from Q indicates higher Tg values of 62.6 and 88.8 °C for PDLLA and PL...

Today's consumer electronics are made from nonrenewable and toxic components. They are also rigid, bulky, and manufactured in an energy-inefficient manner via CO2-generating routes. Though petroleum-based polymers such as polyethylene terephthalate and polyethylene naphthalate can address the rigidity issue, they have a large carbon footprint and generate harmful waste. Scalable routes for manufacturing electronics that are both flexible and ecofriendly (Fleco) could address the challenges in the field. Ideally, such substrates must incorporate into electronics without compromising device performance. In this work, we demonstrate that a new type of wood-based [nanocellulose (NC)] material made via nanosilicate (NS) reinforcement can yield flexible electronics that can bend and roll without loss of electrical function. Specifically, the NSs interact electrostatically with NC to reinforce thermal and mechanical properties. For instance, films containing 34 wt % of NS displayed an increased young's modulus (1.5 times), thermal stability (290 → 310 °C), and a low coefficient of thermal expansion (40 ppm/K). These films can also easily be separated and renewed into new devices through simple and low-energy processes. Moreover, we used very cheap and environmentally friendly NC from American Value Added Pulping (AVAP) technology, American Process, and therefore, the manufacturing cost of our NS-reinforced NC paper is much cheaper ($0.016 per dm-2) than that of conventional NC-based substrates. Looking forward, the methodology highlighted herein is highly attractive as it can unlock the secrets of Fleco electronics and transform otherwise bulky, rigid, and "difficult-to-process" rigid circuits into more aesthetic and flexible ones while simultaneously bringing relief to an already-overburdened ecosystem.

Functional 3D components such as perfusion channels and mechanical actuation elements at cellular length scales can support cell survival and tissue maturation in tissue modeling devices. These advanced requirements call for increasingly complex materials and 3D fabrication methods. Here, a high-resolution dual-material 3D printing concept is developed, where distinct materials are produced locally by orthogonal chemical reactions depending on the illumination wavelength. A tough, stiff epoxy network results from cationic polymerization in UV light, while a soft and diffusion-open hydrogel forms by free-radical polymerization initiated by blue light. Thus, dual-exposure allows for selection of material properties in every voxel, while retaining the 3D design flexibility associated with stereolithography. This enables single-process fabrication of devices integrating mechanically stable chip-to-world interconnects and compliant, diffusion-open perfusable channel components of 150 µm in width and height, while also allowing structural and mechanical feature dimensions down to 60 µm. A perfusion chip capable of creating a stable uniaxial chemical gradient by passive dye diffusion through hydrogel sections, and a negative Poisson ratio structure based on the interplay between stiff rotators and compliant hinges, are manufactured as proof-of-concept microdevices. Lastly, week-long culture of hydrogel-encapsulated human liver cells demonstrates the cytocompatibility of both materials.

We present structural relaxation studies of a polystyrene star polymer after cessation of high-rate extensional flow. During the steady-state flow, the scattering pattern shows two sets of independent correlations peaks, reflecting the structure of a polymer confined in a fully oriented three-armed tube. Upon cessation of flow, the relaxation constitutes three distinct regimes. In a first regime, the perpendicular correlation peaks disappear, signifying disruption of the virtual tube. In a second regime, broad scattering arcs emerge, reflecting relaxation from highly aligned chains to more relaxed, still anisotropic form. New entanglements dominate the last relaxation regime where the scattering pattern evolves to a successively elliptical and circular pattern, reflecting relaxation via reptation.

Reanalysis of an asymmetric poly(ethylene

Alginates, serving as hydrocolloids in the food and pharma industries, form particles at pH < 4.5 with positively charged proteins, such as β-lactoglobulin (β-Lg). Alginates are linear anionic polysaccharides composed of 1,4-linked β-d-mannuronate (M) and α-l-guluronate (G) residues. The impact of M and G contents and pH is investigated to correlate with the formation and size of β-Lg alginate complexes under relevant ionic strength. It is concluded, using three alginates of M/G ratios 0.6, 1.1, and 1.8 and similar molecular mass, that β-Lg binding capacity is higher at pH 4.0 than at pH 2.65 and for high M content. By contrast, the largest particles are obtained at pH 2.65 and with high G content. At pH 4.0 and 2.65, the stoichiometry was 28-48 and 3-10 β-Lg molecules bound per alginate, respectively, increasing with higher M content. The findings will contribute to the design of formation of the desired alginate-protein particles in the acidic pH range.

Reanalysis of an asymmetric poly(ethylene-alt-propylene)-block-polydimethylsiloxane (PEP-PDMS) diblock copolymer first investigated in 1999 has revealed a rich phase behavior including a dodecagonal quasicrystal (DDQC), a Frank-Kasper σ phase, and a body-centered cubic (BCC) packing at high temperature adjacent to the disordered state. On subjecting the sample to large amplitude oscillatory shear well below the σ-BCC order-order transition temperature (TOOT), small-angle X-ray scattering evidenced the emergence of a twinned BCC phase that, on heating, underwent a phase transition to an unusually anisotropic DDQC state. Surprisingly, we observe no evidence of this apparent epitaxy on heating or cooling through the equilibrium σ-BCC transition. We rationalize these results in terms of a shear-induced order-order transition and an apparent BCC-DDQC epitaxy favored by micelle translation-mediated ordering dynamics far below TOOT.

A key initiating step in atherosclerosis is the accumulation and retention of apolipoprotein B complexing lipoproteins within the artery walls. In this work, we address this exact initiating mechanism of atherosclerosis, which results from the oxidation of low-density lipoproteins (oxLDL) using therapeutic nanogels. We present the development of biocompatible polyethylene glycol (PEG) cross-linked nanogels formed from a single simultaneous cross-linking and co-polymerization step in water without the requirement for an organic solvent, high temperature, or shear stress. The nanogel synthesis also incorporates in situ noncovalent electrostatically driven template polymerization around an innate anti- inflammatory and anti-oxidizing paraoxonase-1 (PON-1) enzyme payload-the release of which is triggered because of matrix metalloproteinase responsive elements instilled in the PEG cross-linker monomer. The results obtained demonstrate the potential of triggered release of the PON-1 enzyme and its efficacy against the production of ox-LDL, and therefore a reduction in macrophage foam cell and reactive oxygen species formation.

The intravaginal route of administration can be exploited to treat local diseases and for systemic delivery. In this work, we developed an alginate/chitosan membrane sufficiently stable in a simulated vaginal fluid and able to dissolve over time at a very slow and linear rate. The membrane demonstrated good mechanical properties both in its swollen and dry form. As a study case, we evaluated the viability of this potential drug delivery system for the treatment of bacterial vaginosis, a common disease affecting women in their reproductive age. Metronidazole was effectively included in the alginate/chitosan membrane and its bactericide effect was demonstrated against Staphylococcus aureus and Gardnerella vaginalis, simultaneously showing good biocompatibility with a cervix epithelial cell line. Since this alginate/chitosan membrane is stable in a simulated vaginal environment, is easy to fabricate and can be used for the controlled release of a model drug, it represents a promising drug delivery system for local intravaginal applications.

Nanoporous zirconia with high surface area and crystallinity has a wide range of industrial applications, such as in inorganic exchangers for ion exchange columns, catalyst substrates, and packing material for HPLC. Spherical particles of crystalline nanoporous zirconia are highly desired in various industries due to easy handling of the materials in a fluidized bed. Here, spray drying was adopted to produce spherical nanoporous zirconia powders in both laboratory scale and pilot plant scale. Effect of salts on spray-dried ZrO2 powders and their crystallization behavior was studied. It was found that addition of salts to the zirconia precursors has a huge effect on the crystallization of nanoporous zirconia powders. These results have a great impact on the development of microspheres of nanocrystalline ZrO2 and potentially open up a new opportunity to the low-cost production of porous ceramic microspheres with the salt templating method, in general.

Fundamental understanding of microphase separation in ABC miktoarm copolymers is vital to access a plethora of nonconventional morphologies. Miktoarm stars based on poly(cis 1,4-isoprene) (I), poly(styrene) (S), and poly(2-vinylpyridine) (V) are model systems, which allow systematic studies of the effects of composition, chemical microstructure, and temperature on the thermodynamics of microphase separation. Eleven ISV-x (I:S:V = 1:1:x, v:v:v) miktoarm copolymers were synthesized by anionic polymerization affording well-defined copolymers with a variable V arm. Equilibrium bulk morphologies of all samples, as evidenced by smallangle X-ray scattering, transmission electron microscopy (TEM), and self-consistent field theory, showed a systematic transition from lamellae (x ≈ 0–0.2) to [8.8.4] tiling (x ≈ 0.6–0.9) to cylinders inundulating lamellae (x ≈ 2–4) and, finally, to hexagonally packed core–shell cylinders (x ≈ 5–8). Chemical microstructure of the I arm [poly(cis 1,4-isoprene)] versus poly(3,4-isoprene) is shown to play important role in affecting morphological behavior. To reconcile differences between ISV-x star morphologies reported in the literature and those reported herein, even for the same composition, effects of the microstructure of I arm on the Flory–Huggins parameter between I and V arms were taken into account in a qualitative manner.

The interfacial shear strength (IFSS) is commonly used for evaluating the adhesion at the interface between fibre and matrix. A glass fibre/epoxy matrix system was investigated. The surface coatings applied to glass fibres may result in a discrepancy in the amine:epoxide group ratio between the interface and the bulk matrix, consequently moving the ratio away from the optimum stoichiometric ratio most often used. The amine:epoxide group ratio in the matrix was varied to obtain the optimum ratio at the interface. The study found that the amine:epoxide ratio influenced the IFSS with an optimum just below the stoichiometric ratio. The microbond test was conducted in a thermal mechanical analyser (TMA) to determine the IFSS thus revealing an inverse dependency on the testing temperature: an increased testing temperature yields a decrease of IFSS. IFSS determined at temperatures below the glass transition temperature displays a decreasing trend at high amine:epoxide ratio whereas IFSS measured at testing temperatures above the glass transition temperature steadily increases as the amine:epoxide ratio increases. The microbond test was conducted using both a tensile tester and a TMA setup. The two microbond test setups yielded results with same behaviour of the IFSS as a function of the amine:epoxide ratio.

Alginate is an anionic polysaccharide capable of forming insoluble particles with proteins. Hence, alginate has potential as a protein carrier. However, the role of physical properties of the polysaccharide, such as degree of polymerization (DPn) and mannuronic/guluronic acid ratio, remains to be fully explored. Particle formation of a high and a low molar mass alginate (ALG) with β-lactoglobulin (BLG) at pH 2-8 depends on the average DPn (HMW-ALG: 1.59·103; LMW-ALG: 0.23·103) and the mannuronic/guluronic acid ratio (1.0; 0.6) as supported by using ManA6 and GulA6 as models. Dynamic light scattering (DLS) showed that particles of BLG with either of the two ALGs have essentially the same hydrodynamic diameter (D H) at pH 3 and 2, while at pH 4 particles of LMW-ALG/BLG have larger D H than of HMW-ALG/BLG. At pH 5-8 no significant particle formation was observed. ManA6 did not form insoluble particles at pH 2-8, while GulA6 formed insoluble particles, albeit only at pH 4. K d was approximately 10-fold higher for LMW-ALG/BLG than HMW-ALG/BLG and 3 orders of magnitude higher for an alginate trisaccharide/BLG complexation as determined by isothermal titration calorimetry (ITC). The alginate trisaccharide did not form insoluble particles with BLG at pH 3 and 4, though interaction still occurred. δH app and molar stoichiometry of BLG in the complexes with the two ALGs differed by a factor of 7, as did their DPn, which thus affected the interaction strength, but not the BLG content. At pH 4 the BLG content doubled in the particle due to BLG dimerization. The findings emphasize the importance of DPn, mannuronic/guluronic acid ratio and pH in formulations containing alginate/whey protein particles.

Transglutaminase (TG) catalyzes formation of covalent bonds between lysine and glutamine side chains and has applications in manipulation of food structure. Physical properties of a whey protein mixture (SPC) denatured either at elevated pH or by heat-treatment and followed by TG catalyzed crosslinking, have been characterised using dynamic light scattering, size exclusion chromatography, flourescence spectroscopy and atomic force microscopy. The degree of enzymatic crosslinking appeared higher for pH- than for heat-denatured SPC. The hydrophobic surface properties depended on the treatment, thus heating caused the largest exposure of the hydrophobic core of SPC proteins, which was decreased by crosslinking. The particle size of the treated SPC samples increased upon crosslinking by TG. Moreover, the particle morphology depended on the type of denaturing treatment, thus heat-treated SPC contained fibrillar structures, while pH-denatured SPC remained globular as documented by using atomic force microscopy. Finally, the in vitro digestability of the different SPC samples was assessed under simulated gastric and intestinal conditions. Notably heat-treatment was found to lower the gastric digestion rate and enzymatic crosslinking reduced both the gastric and the intestinal rate of digestion. These characteristics of the various SPC samples provide a useful basis for design of isoenergic model foods applicable in animal and human studies on how food structure affects satiety.

Interactions of exopolysaccharides and proteins are of great importance in food science, but complicated to analyze and quantify at the molecular level. A surface plasmon resonance procedure was established to characterize binding of seven structure-determined, branched hetero-exopolysaccharides (HePSs) of 0.14–4.9 MDa from lactic acid bacteria to different milk proteins (β-casein, κ-casein, native and heat-treated β-lactoglobulin) at pH 4.0–5.0. Maximum binding capacity (RUmax) and apparent affinity (KA,app) were HePS- and protein-dependent and varied for example 10- and 600-fold, respectively, in the complexation with native β-lactoglobulin at pH 4.0. Highest RUmax and KA,app were obtained with heat-treated β-lactoglobulin and β-casein, respectively. Overall, RUmax and KA,app decreased 6- and 20-fold, respectively, with increasing pH from 4.0 to 5.0. KA,app was influenced by ionic strength and temperature, indicating that polar interactions stabilize HePS–protein complexes. HePS size as well as oligosaccharide repeat structure, conferring chain flexibility and hydrogen bonding potential, influence the KA,app.

By combining poly(1,4-isoprene) (PI) with poly(ferrocenylmethyl methacrylate) (PFMMA) in a diblock copolymer structure by means of anionic polymerization we obtained narrowly dispersed PI-b-PFMMA copolymers with molecular weight ranging from 13000 to 62000 g/mol. The products were stable up to 228 °C, according to thermal gravimetry, which allowed us to further investigate their viscoelastic and X-ray scattering properties at elevated temperature by rheology and SAXS, respectively. For PI-b-PFMMA with total molecular weight 13400 g/mol a phase transition at 105 °C was identified leading to the segmental mixing at T > 105 °C and microphase separation at T

Cell or tissue stretching and strain are present in any in vivo environment, but is difficult to reproduce in vitro. Here, we describe a simple method for casting a thin (about 500 μm) and soft (about 0.3 kPa) hydrogel of gelatin and a method for characterizing the mechanical properties of the hydrogel simply by changing pressure with a water column. The gelatin is crosslinked with mTransglutaminase and the area of the resulting hydrogel can be increased up 13-fold by increasing the radial water pressure. This is far beyond physiological stretches observed in vivo. Actuating the hydrogel with a radial force achieves both information about stiffness, stretchability, and contractability, which are relevant properties for tissue engineering purposes. Cells could be stretched and contracted using the gelatin membrane. Gelatin is a commonly used polymer for hydrogels in tissue engineering, and the discovered reversible stretching is particularly interesting for organ modeling applications.

In a quest for renewable and highly efficient energy storage devices, carbonaceous hydrogels obtained from biopolymers have received much attention owing to their multifunctional properties [1]. The ability to fine-tune the structures of these hydrogels and the prospects of fabricating 3D hydrogels-based carbon electrodes with highly porous and interconnected nanostructure is believed to provide efficient migration of electrolyte ions and electrons. Even though additive manufacturing (AM) of hydrogels with 3D structures could simplify the fabrication, the printability of each material varies greatly. Furthermore, the mechanical properties of hydrogels are often too weak to withstand the printing of structures with a certain height [2]. Herein, we demonstrate a facile and versatile method for the fabrication of novel and highly porous 3D carbon aerogel electrodes from bio-hydrogels based on additive manufacturing assisted solvent casting process followed by freeze drying and pyrolysis. Firstly, the negative templates with the required resolution and geometry were 3D printed using high-resolution stereolithography (SLA) based AM technology to be used as master molds and the pattern were transferred to the biopolymeric hydrogels during ionic crosslinking induced self-assembly, leading to gelation. After completion of the gelling process, the casted hydrogel was removed from the master mold, washed with deionized water, frozen using solid carbon dioxide (dry ice) and lyophilized (freeze-dried) to preserve the structure. The lyophilized free-standing aerogels were then converted to free-standing 3D pyrolytic carbon aerogels in a high-temperature tubular furnace at 900°C under a nitrogen environment. Different characterization techniques such as FTIR, BET, SEM, Raman, XRD and XPS were employed to access the influence of the process parameters on the final microstructure of the 3D carbon aerogels. The as-prepared 3D free-standing carbon aerogel when used as a binder-free electrode showed outstanding charge storage capability and kinetics arising from interconnected 3D porous channels. The versatility of this approach was further verified by the successful preparation of novel multifunctional 3D free-standing carbon aerogel hybrids using GO, CNT and/or metal oxides and its application as a structured binder-free supercapacitor electrode with improved electrochemical performance. With the advantageous features of synergistically regulating the structure and composition, the proposed method combining AM and casting could be used as a versatile tool to develop structured bio-hydrogels, to be used as precursor material for constructing novel architectured free-standing carbon electrode materials with well-defined geometry and controlled pore size distribution. The final shape of carbon electrode depends on the 3D geometry of the additive manufactured negative template used for the replication during solvent casting. This technique would broaden the library of hydrogels materials that could be constructed freely in three-dimensions for the fabrication of structured and free-standing porous bio-carbon based electrodes for high-performance supercapacitor application. References [1] Wu, Xi-Lin, and An-Wu Xu. "Carbonaceous hydrogels and aerogels for supercapacitors." Journal of Materials Chemistry A 2, no. 14 (2014): 4852-4864. [2] Li, Huijun, Cavin Tan, and Lin Li. "Review of 3D printable hydrogels and constructs." Materials & Design 159 (2018): 20-38. Acknowledgements The authors greatly acknowledge the funding provided by the European Research Council under the Horizon 2020 framework programme grant no. 772370-PHOENEEX. Figure 1

Narrowly dispersed diblock copolymers containing poly(methyl methacrylate) [PMMA] or poly(nonafluorohexyl methacrylate) [PF9MA] as the first block and poly(ferrocenylmethyl methacrylate) [PFMMA] as the second block, were prepared by anionic polymerization for the first time. Disordered bulk morphologies in the case of PMMA-b-PFMMA were observed and explained in terms of low Flory–Huggins interaction parameter (χ ≤ 0.04). In the case of PF9MA-b-PFMMA hexagonally packed cylinder morphology (HEX) was substantiated from TEM and SAXS observations. Furthermore, high incompatibility between PF9MA and PFMMA blocks allowed for the formation of well-ordered ferrocene containing cylinders on silica substrate upon exposure of the thin films to a saturated solvent vapor. It was shown that the cylinder orientation, parallel or perpendicular to the surface, could easily be controlled by appropriate choice of the solvent and without the need for preliminary surface modification, for example by means of grafted brush layer. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016

The effect of formation and modification methods on the physical properties of polymersomes is critical for their use in applications relying on their ability to mimic functional properties of biological membranes. In this study, we compared two formation methods for polymersomes made from polybutadiene-polyethylene oxide diblock copolymers: detergent-mediated film rehydration (DFR) and solvent evaporation (SE). DFR-prepared polymersomes showed a three times higher permeability compared to SE-prepared polymersomes as revealed by stopped-flow light scattering. SE-prepared polymersomes broke down faster to structures

Nanostructured graphene exhibits many intriguing properties. For example, precisely controlled graphene nanomeshes can be applied in electronic, photonic, or sensing devices. However, fabrication of nanopatterned graphene with periodic supperlattice remains a challenge. In this work, periodic graphene nanomesh was fabricated by photocatalysis of single-layer graphene suspended on top of TiO2-covered nanopillars, which were produced by combining block copolymer nanolithography with atomic layer deposition. Graphene nanoribbons were also prepared by the same method applied to a line-forming block copolymer template. This mask-free and nonchemical/nonplasma route offers an exciting platform for nanopatterning of graphene and other UV-transparent materials for device engineering.

We present a method to make continuous multi-material structures from a monomer solution that becomes a soft hydrogel when exposed to blue light and a hard solid when exposed to UV light. We show that the material can be varied between a hard epoxy material to a several hundred times softer poly(ethylene glycol)-diacrylate material. Moreover, the elastic properties of the material depend on both the wavelength of and exposure time of the light, which is used to produce a material with an elasticity gradient. We expect our material to find use in a range of fields, with immediate applications as 2D sheets with tunable mechanical properties for cell durotaxis studies, and 3D stereolithographically printed tissue mimicks, for example, for disease models and tissue engineering. Spatially resolved photo-polymerization of a mixture of epoxy and acrylate monomers can be used to make multi-material structure, with unique freedom to polymerize each monomer individually. The elastic compressive properties of the material are shown to be fully tunable from 20 MPa depending on the light exposure time. This is used to make a functionally graded continuous material with a large variation in elastic properties. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1195–1201

Biomacromolecules 19(7), 2905 - 2912 (2018). doi:10.1021/acs.biomac.8b00471, The dimeric structure of bovine β-lactoglobulin A (BLGA) at pH 4.0 was solved to 2.0 Å resolution. Fitting the BLGA pH 4.0 structure to SAXS data at low ionic strength (goodness of fit R-factor = 3.6%) verified the dimeric state in solution. Analysis of the monomer–dimer equilibrium at varying pH and ionic strength by SAXS and scattering modeling showed that BLGA is dimeric at pH 3.0 and 4.0, shifting toward a monomer at pH 2.2, 2.6, and 7.0 yielding monomer/dimer ratios of 80/20%, 50/50%, and 25/75%, respectively. BLGA remained a dimer at pH 3.0 and 4.0 in 50–150 mM NaCl, whereas the electrostatic shielding raised the dimer content at pH 2.2, 2.6, and 7.0, i.e., below and above the pI. Overall, the findings provide new insights into the molecular characteristics of BLGA relevant for dairy product formulations and for various biotechnological and pharmaceutical applications., Published by American Chemical Soc., Columbus, Ohio

Despite a very large number of bacterial exopolysaccharides have been reported, detailed knowledge on their molecular structures and associative interactions with proteins is lacking. Small-angle X-ray scattering, dynamic light scattering and analytical ultracentrifugation (AUC) were used to characterize the interactions of six lactic acid bacterial heteroexopolysaccharides (HePS-1–HePS-6) with β-lactoglobulin (BLG). Compared to free HePSs, a large increase in the X-ray radius of gyration RG, maximum length L and hydrodynamic diameter dH of HePS-1–HePS-4 mixed with BLG revealed strong aggregation, the extent of which depended on the compact conformation and degree of branching of these HePSs. No significant effects were observed with HePS-5 and HePS-6. Turbidity and AUC analyses showed that both soluble and insoluble BLG–HePS complexes were formed. The findings provide new insights into the role of molecular structures in associative interactions between HePSs and BLG which has relevance for various industrial applications.

We present structural small-angle neutron scattering studies of a three-armed polystyrene star polymer with short deuterated segments at the end of each arm. We show that the form factor of the three-armed star molecules in the relaxed state agrees with that of the random phase approximation of Gaussian chains. Upon exposure to large extensional flow conditions, the star polymers change conformation resulting in a highly stretched structure that mimics a fully extended three-armed tube model. All three arms are parallel to the flow, one arm being either in positive or negative stretching direction, while the two other arms are oriented parallel, right next to each other in the direction opposite to the first arm.

In this work we have performed a detailed analysis of enzymatic degradation of amorphous poly (d, l-lactide) (PDLLA) by measuring the resonance frequencies of polymer coated microcantilevers before and after degradation. The miniaturized cantilever system provides a fast analysis of the biodegradation rate of PDLLA with a minute amount of sample and without the need of thermal and chemical acceleration. The degradation rate of the polymer has been estimated by multilayer cantilever theory and model simulation. A bulk degradation rate of 0.24 μg mm-2 hour-1 is estimated which agrees well with values reported in literature. The role of enzyme concentrations, pre-hydration in buffer, surface morphologies of PDLLA films and adsorption time of enzymes on the rate of degradation has been investigated. An increase in degradation rate is observed with an increase in enzyme concentration and after pre-hydration in buffer. A polymer film with a non-uniform surface degrades faster than the uniform one due to the preference of enzyme attack at film defects. A threshold time of around 3 h is estimated for irreversible enzyme adsorption on the polymer surface after which degradation can proceed even in buffer solution in the absence of enzyme.

The present invention relates to compositions where a substrate is liable to catch fire such as bituminous products, paints, carpets or the like. The invention relates to a composition comprising 40-95 weight % of a substrate to be rendered fire resistant such as bituminous material or paint, carpets which substrate is mixed with 5-60 weight % of a fire retardant component. The invention relates to a fire retardant component comprising or being constituted of attapulgite, and a salt being a source of a blowing or expanding agent, where the attapulgite and the salt are electrostatically connected by mixing and subjecting the mixture of the two components to agitation. Also, the invention relates to compositions comprising 40-95 weight % of a substrate to be rendered fire resistant mixed with 5-60 weight % of a fire retardant according to claim 1 or 2, which fire retardant component is mixed with the substrate or coated onto the substrate or applied as a separate layer to the substrate. The composition might additionally comprise between 0 -60 weight % of 20 other materials functioning as filler, plasticizer or the like.

Poly(ethylene carbonate) (PEC) is a unique biomaterial showing significant potential for controlled drug delivery applications. The current study investigated the impact of the molecular weight on the biological performance of drug-loaded PEC films.Following the preparation and thorough physicochemical characterization of diverse PEC (molecular weights: 85, 110, 133, 174 and 196 kDa), the degradation and drug release behavior of rifampicin- and bovine serum albumin-loaded PEC films was investigated in vitro (in the presence and absence of cholesterol esterase), in cell culture (RAW264.7 macrophages) and in vivo (subcutaneous implantation in rats). All investigated samples degraded by means of surface erosion (mass loss, but constant molecular weight), which was accompanied by a predictable, erosion-controlled drug release pattern. Accordingly, the obtained in vitro degradation half-lives correlated well with the observed in vitro halftimes of drug delivery (R2 = 0.96). Here, the PEC of the highest molecular weight resulted in the fastest degradation/drug release. When incubated with macrophages or implanted in animals, the degradation rate of PEC films superimposed the results of in vitro incubations with cholesterol esterase. Interestingly, SEM analysis indicated a distinct surface erosion process for enzyme-, macrophage- and in vivo-treated polymer films in a molecular weight-dependent manner. Overall, the molecular weight of surface-eroding PEC was identified as an essential parameter to control the spatial and temporal on-demand degradation and drug release from the employed delivery system.

Knowledge on molecular structure of exopolysaccharides (EPSs) and their roles in the associative interactions with proteins is essential to understand the relationship between their structure, physical and rheological properties. Despite their importance, no detailed molecular characterization of bacterial EPSs and their associative interactions with proteins have been reported up to now. By combining X-ray solutionscattering (SAXS), dynamic light scattering (DLS) and analytical ultracentrifugation (AUC) in conjunction with scattering modeling, we have characterized four different heteroexopolysaccharides (HePS-1–HePS-4) from lactic acid bacteria (LAB) and their interactions with β-lactoglobulin. We have previously shown that these HePSs exhibited a compact conformation in solution. Here, SAXS data for HePSs (HePS-1–HePS-4) complexes with β-lactoglobulin showed that β-lactoglobulin aggregated strongly with these HePSs. β-lactoglobulin exists as a dimer at pH 4 in the absence of HePSs. When mixed with HePSs, SAXS analysis showed that β-lactoglobulin formed large aggregates. DLS also showed formation of large aggregates of β-lactoglobulin with HePSs, thus validating SAXS data. Turbidity and AUC data indicated that both soluble and insoluble BLG–HePSs complexes were formed. This study provides new insights into the role of molecular structures in associative interactions between HePSs and BLG which has relevance for various industrial applications.

Molecular structures of exopolysaccharides are required to understand their functions and the relationships between the structure and physical and rheological properties. Small-angle X-ray scattering and dynamic light scattering were used in conjunction with molecular modeling to characterize solution structures of three lactic acid bacterial heteroexopolysaccharides (HePS-1, HePS-2, and HePS-3). Values of radius of gyration RG, cross-sectional radius of gyration Rxs, approximate length L, and hydrodynamic diameter were not directly proportional to the molar mass and indicated the HePSs adopted a compact coil-like rather than an extended conformation. Constrained molecular modeling of 15000 randomized HePS-1 conformers resulted in five best-fit structures with R factor of 3.9-4.6% revealing random coil-like structure. φ and ψ angle analysis of glycosidic linkages in HePS-1 structures suggests Galf residues significantly influence the conformation. Ab initio scattering modeling of HePS-2 and HePS-3 gave excellent curve fittings with χ2 of 0.43 and 0.34 for best-fit models, respectively, compatible with coil-like conformation. The findings disclose solution behavior of HePS relevant for their interactions with biomacromolecules, for example, milk proteins.

Due to strong mode-confinement, long propagation-distance, and unique tunability, graphene plasmons have been widely explored in the mid-infrared and terahertz windows. However, it remains a big challenge to push graphene plasmons to shorter wavelengths in order to integrate graphene plasmon concepts with existingmature technologies in the near-infrared region. We investigate localized graphene plasmons supported by graphene nanodisks and experimentally demonstratedgraphene plasmon working at 2 μm with the aid of a fully scalable block copolymer selfassembly method. Our results show a promising way to promote grapheneplasmons for both fundamental studies and potential applications in the near-infrared window.

A micelle based nanosensor was synthesized and investigated as a ratiometric pH sensor for use in measurements in living cells by fluorescent microscopy. The nanosensor synthesis was based on self-assembly of an amphiphilic triblock copolymer, which was chemically cross-linked after micelle formation. The copolymer, poly(ethylene glycol)-b-poly(2-aminoethyl methacrylate)-b-poly(styrene) (PEG-b-PAEMA-b-PS), was synthesized by isolated macroinitiator atom transfer radical polymerization that forms micelles spontaneously in water. The PAEMA shell of the micelle was hereafter cross-linked by an amidation reaction using 3,6,9-trioxaundecandioic acid cross-linker. The cross-linked micelle was functionalized with two pH sensitive fluorophores and one reference fluorophore, which resulted in a highly uniform ratiometric pH nanosensor with a diameter of 29 nm. The use of two sensor fluorophores provided a sensor with a very broad measurement range that seems to be influenced by the chemical design of the sensor. Cell experiments show that the sensor is capable of monitoring the pH distributions in HeLa cells.

Based on a parent diblock copolymer of poly(styrene)-b-poly(methacrylic acid), PS-b-PMAA, linear-b-amphiphilic comb (L-b-AC) ionic supramolecules [Soft Matter 2013, 9, 1540-1555] are synthesized in which the poly(methacrylate) backbone of the ionic supramolecular AC-block is neutralized by alkyl (Cn; n = 8, 12, and 16) trimethylammonium counterions (i.e., side chains) at various ion (pair) fractions X [i.e., counterion/side-chain grafting density; X = number of alkyl counterions (i.e., side chains) per acidic group of the parent PMAA block] these L-b-AC ionic supramolecules exhibit a spherical-in-lamellar hierarchical self-assembly. For these systems, (1) the effective Flory-Huggins interaction parameter between L- and AC-blocks chi'(Cn/x) was extracted, and (2) analysis of the lamellar microdomains showed that when there is an increase in X, alkyl counterion (i.e., side chain) length l(sc), or both, there is an increase in both the average interfacial area per block junction Sigma and the thickness of the microlayer of the AC-block d(Ac).

Chemical vapor deposited graphene is nanopatterned by a spherical block-copolymer etch mask. The use of spherical rather than cylindrical block copolymers allows homogeneous patterning of cm-scale areas without any substrate surface treatment. Raman spectroscopy was used to study the controlled generation of point defects in the graphene lattice with increasing etching time, confirming that alongside the nanomesh patterning, the nanopatterned CVD graphene presents a high defect density between the mesh holes. The nanopatterned samples showed sensitivities for NO2 of more than one order of magnitude higher than for non-patterned graphene. NO2 concentrations as low as 300 ppt were detected with an ultimate detection limit of tens of ppt. This is so far the smallest value reported for not UV illuminated graphene chemiresistive NO2 gas sensors. The drastic improvement in the gas sensitivity is believed to be due to the high adsorption site density, thanks to the combination of edge sites and point defect sites. This work opens the possibility of large area fabrication of nanopatterned graphene with extreme density of adsorption sites for sensing applications., Comment: The final publication will be aviable http://www.springer.com/materials/nanotechnology/journal/12274

Metaphase chromosome spreading is the most crucial step required for successful karyotyping and FISH analysis. These two techniques are routinely used in cytogenetics to assess the chromosome abnormalities. The spreading process has been studied for years but it is still considered an art more than a science. The chromosome spreading greatly depends on the environmental conditions such as humidity and temperature, which govern the evaporation of fixative, in which the cells are suspended. The spreading is normally performed manually in ambient conditions on glass slides, which are hydrophilic, and thus allow for better quality spreads. Further cytogenetic analysis depends on the quality of the spreads, which is dependent on the skills of the personnel and is thus limited to laboratory settings. Here, we present a semi-closed microfluidic chip for preparation of the metaphase spreads on a glass and a Topasr substrate rendered more hydrophilic by oxygen plasma treatment coupled with photografting. The device consists of a microfluidic chamber with perfusion holes that facilitate the evaporation of fixative and reliable formation of the spreads. The usability of the chromosome spreads formed on the glass and the Topasr slide is tested by performing FISH analysis.

A modified and improved photografting procedure of Topas® surface hydrophilization is investigated in order to obtain stable modification of the polymer for long term storage. The achieved hydrophilicity and monitoring of the wettability during one month of storage are presented as well as a description of the optimal cleaning procedure and storage conditions to maintain the modified surface. Three minutes of oxygen plasma activation followed by 4 min of acrylic acid UV-photografting at 50 °C leads to the most stable hydrophilicity that was characterized by an initial water contact angle of 53.5° ± 1.2°. Storage of the modified material in cold water at 4 °C and refraining from ultrasonic cleaning limit water contact angle increase to 5° over 30 days. In comparison with pristine hydrophobic Topas, the proposed treatment improves chromosome spreading ability significantly.

We report on the systematic investigation of the optical properties of a selectively grown quantum dot gain material assisted by block-copolymer lithography for potential applications in active optical devices operating in the wavelength range around 1.55 um and above. We investigated a new type of diblock copolymer PS-b-PDMS (polystyrene-block-polydimethylsiloxane) for the fabrication of silicon oxycarbide hard mask for selective area epitaxy of InAs/InP quantum dots. An array of InAs/InP quantum dots was selectively grown via droplet epitaxy. Our detailed investigation of the quantum dot carrier dynamics in the 10-300 K temperature range indicates the presence of a density of states located within the InP bandgap in the vicinity of quantum dots. Those defects have a substantial impact on the optical properties of quantum dots., Comment: 11 pages, 5 figures, 1 table

We compare viscoelastic properties of several polystyrene solutions and melts with the same number of entanglements. It is demonstrated that the modulus and time can be shifted such that the linear viscoelastic properties are identical provided the number of entanglements are identical. However the nonlinear properties in strong extensional flow are different with polymer solutions showing markedly stronger extensional hardening than the corresponding melts. While increased chain extensibility for solutions may provide part of the explanation, it is demonstrated that other mechanisms are needed for a full explanation for the differences between solutions and melts.

In this work we have performed a detailed study of the influence of various parameters on spray coating of polymer films. Our aim is to produce polymer films of uniform thickness (500 nm to 1 μm) and low roughness compared to the film thickness. The coatings are characterized with respect to thickness, roughness (profilometer), and morphology (optical microscopy). Polyvinylpyrrolidone (PVP) is used to do a full factorial design of experiments with selected process parameters such as temperature, distance between spray nozzle and substrate, and speed of the spray nozzle. A mathematical model is developed for statistical analysis which identifies the distance between nozzle and substrate as the most significant parameter. Depending on the drying of the sprayed droplets on the substrate, we define two broad regimes, "dry" and "wet". The optimum condition of spraying lies in a narrow window between these two regimes, where we obtain a film of desired quality. Both with increasing nozzle-substrate distance and temperature, the deposition moves from a wet state to a dry regime. Similar results are also achieved for solvents with low boiling points. Finally, we study film formation during spray coating with poly (D,L-lactide) (PDLLA). The results confirm the processing knowledge obtained with PVP and indicate that the observed trends are identical for spraying of other polymer films.

A new cross-linked micelle pH nanosensor design was investigated. The nanosensor synthesis was based on self-assembly of an amphiphilic triblock copolymer, poly(ethylene glycol)-b-poly(2-amino ethyl methacrylate)-b-poly(coumarin methacrylate) (PEG-b-PAEMA-b-PCMA), which was synthesized by isolated macroinitiator atom transfer radical polymerization. Micelles were formed by PEG-b-PAEMA-b-PCMA self-assembly in water, giving micelles with an average diameter of 45 nm. The PCMA core was employed to utilize coumarin-based photoinduced cross-linking in the core of the micelles, which was performed by UV irradiation (320 nm < λ < 500 nm), and the progress of the cross-linking was monitored by UV spectroscopy. The formed cross-linked core–shell–corona micelle was converted into ratiometric pH nanosensors by binding the pH-sensitive fluorophores oregon green 488 and 2′,7′-bis-(2-carboxyethyl)-5-(and-6) carboxyfluorescein and a reference fluorophore Alexa 633 to the PAEMA shell region of the micelles. Fluorescence ...