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This work describes the studies on the interaction of Midazolam (MDZ) with agar gel salt bridge supported bilayer lipid membrane (sb-BLM) using electrochemical impedance spectroscopy, cyclic voltammetry and potentiodynamic polarization methods The non-specific interaction of MDZ with sb-BLM was studied by following the dose-dependent changes in its electrical properties. MDZ was found to interact with the membrane surface at lower concentrations and impart a tightening effect which is indicated by the increase in capacitance of the membrane. At higher concentrations, MDZ molecules get partitioned into the BLM phase leading to fluidization of the membrane and in turn an increase in ionic conductance across BLM phase. Ionization of midazolam hydrochloride (MDZH + Cl − ) depends on the ionic strength of the medium supporting the membranes. The ionic form of the drug interacts preferentially with the polar region of the membrane while the unionized forms are found to interact strongly with its hydrocarbon core regions. Thus, the overall electrical properties of the sb-BLM, observed with MDZ doses, are a consequence of the competitive effects brought about by these drug species on both the regions of the sb-BLMs. [ABSTRACT FROM AUTHOR]

Near infrared absorber materials for organic solar cells are needed to cover larger parts of the solar spectrum and, therefore, achieve higher short circuit current densities. We present a push-pull chromophore with a quinoid merocyanine structure (QM1) as donor material in vacuum deposited organic solar cells with a thin film absorption up to 1100 nm. A blue shift of the main absorption peaks of the thin film as compared to the solution indicates H-aggregation of the material. Morphology investigations using scanning electron microscopy and electron diffraction reveal a crystalline growth in nanowires, with lengths of hundreds of nanometers to a few micrometers, and diameters of a few tens of nanometers. Organic solar cells incorporating a blend of QM1 with C 60 reach power conversion efficiencies up to 1.9% under 1 sun illumination with an external quantum efficiency of over 18% from 600 nm to 1000 nm. [ABSTRACT FROM AUTHOR]

In this study we demonstrate an easy solution-processed highly efficient deep-blue polymer light-emitting diode (PLED) via a simple one-step coating of self-assembly hole injection/transport nanocomposites to achieve both a finer hole ohmic contact and an increased light outcoupling, which is the first time report about both the optical and electrical optimization without necessitating changes in the design or structure of the wide bandgap deep-blue PLEDs themselves. The contact angle and surface energy measurement results demonstrate that triazine-based hole injection molecules can vertically migrate towards the bottom PEDOT:PSS layer to obtain a stable minimum of free energy, resulting in an optimal top-to-bottom HOMO energy level arrangement and an improved hole mobility in deep-blue PLEDs. The random surface nanostructure was formed on top of the hole bilayer, leading to the enhancement of light outcoupling verified by transmittance, transmittance haze and light extraction efficiency. Furthermore, in order to explore the reasons of the hole light scattering formation process, a transient drying monitoring technique is applied to track the drying process of the nanostructure films, revealing this approach effectiveness by easily modifying mixing ratios for obtaining different light outcoupling abilities. [ABSTRACT FROM AUTHOR]

A NiO-Fe 2 O 3 based graphene aerogel was employed as a novel catalyst material for the electrochemical oxidation of urea. The three-dimensional aerogels were synthesized by metal ions (Ni 2+ and Fe 3+ )-induced self-assembly using poly(vinyl alcohol) (PVA) as the structural scaffold. The NiO-Fe 2 O 3 /rGO/PVA aerogels were characterized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The catalytic performance of the aerogels for urea electrooxidation in an alkaline medium was investigated by cyclic voltammetry. The NiO-Fe 2 O 3 /rGO/PVA aerogel electrode exhibited significant reduction of the onset oxidation potential (∼90 mV) compared to that of NiO/rGO/PVA. The NiO-Fe 2 O 3 /rGO/PVA aerogel electrode showed a peak current density of 44.6 mA cm −2 at 0.33 M urea in 1.0 M KOH, which was 2.6-fold higher than that of NiO/rGO/PVA electrode. Moreover, the NiO-Fe 2 O 3 /rGO/PVA electrode showed only a 11% loss in the peak current after 200th cycles. [ABSTRACT FROM AUTHOR]

Evaporation induced assembly of colloidal particles in an aerosol droplet has been utilized to synthesize nano-structured porous silica microcapsules comprising of interlocked correlated nano-particles. Morphology of the microcapsules was tuned by controlling the rate of evaporation. In the present work, we demonstrate that such porous capsules can efficiently take up cationic dye from aqueous solution. In-situ UV–vis spectroscopy has been utilized to monitor the time dependence of sorption by these capsules. Small-angle X-ray scattering and scanning electron microscopy have been used to probe the multi-level structure of the powder granules. Thermal analysis was performed on the dye-sorbed granules to investigate the effect of confinement on the thermal degradation behaviour of the dye molecules within the granules. [ABSTRACT FROM AUTHOR]

Organogenesis and morphogenesis have informed our understanding of physiology, pathophysiology, and avenues to create new curative and regenerative therapies. Thus far, this understanding has been hindered by the lack of a physiologically relevant yet accessible model that affords biological control. Recently, three-dimensional ex vivo cellular cultures created through cellular self-assembly under natural extracellular matrix cues or through biomaterial-based directed assembly have been shown to physically resemble and recapture some functionality of target organs. These “organoids” have garnered momentum for their applications in modeling human development and disease, drug screening, and future therapy design or even organ replacement. This review first discusses the self-organizing organoids as materials with emergent properties and their advantages and limitations. We subsequently describe biomaterials-based strategies used to afford more control of the organoid’s microenvironment and ensuing cellular composition and organization. In this review, we also offer our perspective on how multifunctional biomaterials with precise spatial and temporal control could ultimately bridge the gap between in vitro organoid platforms and their in vivo counterparts. Statement of Significance Several notable reviews have highlighted PSC-derived organoids and 3D aggregates, including embryoid bodies, from a development and cellular assembly perspective. The focus of this review is to highlight the materials-based approaches that cells, including PSCs and others, adopt for self-assembly and the controlled development of complex tissues, such as that of the brain, gut, and immune system. [ABSTRACT FROM AUTHOR]

Pd and transition metal oxides functionalized ZSM-5 single crystals with b-axis aligned mesopores (ZSM-5-OM-PdO-MO) were prepared. ZSM-5-OM support was obtained from crystallization of aluminosilicate gels in the presence of cationic polymers. Characterizations indicate abundant nanopores and highly crystalline degree of ZSM-5-OM-PdO-MO, and active species of Pd and transition metals were homogeneously dispersed into ZSM-5-OM, which showed unique interactions and enhanced ability for activating oxygen. Catalytic tests showed that ZSM-5-OM-PdO-MO were highly active and reusable catalysts for selective oxidation of alcohols under aerobic and solvent free condition, which were much better than those of Pd/transition metal oxides functionalized ZSM-5, mesoporous silica of SBA-15, and activated carbon catalysts. [ABSTRACT FROM AUTHOR]

This paper presents an effective and efficient method to fabricate novel fiber optic sensing probes. The new, simple, and low cost approach is based on a 3-D photonic crystal dielectric structure directly deposited on the tip of a multimode optical fiber through the self-assembly of colloidal crystals (CCs) via a vertical deposition technique. Here, the CC is made of polystyrene nanospheres with 200 nm diameter, and the optical fiber is a UV–vis fiber with a core diameter of 200 μm. The obtained fiber probes exhibit a resonant peak at 480 nm and an amplitude enhancement of 3.7 with respect to the bare fiber; these results are highly repeatable. A numerical tool based on a finite element method analysis has been developed to study and analyze the 3-D subwavelength structures. Numerical results are in good agreement with the observed experimental spectra. Moreover, refractive index measurements have been carried out, revealing a sensitivity of up to 445 nm/RIU in the 1.33–1.36 values range. The achieved performances, which have been obtained by using very small active areas and an easy and reliable fabrication procedure, demonstrate the future perspectives of these fiber-optic probes for chemical and biological sensing applications. [ABSTRACT FROM PUBLISHER]

Photonic elastomers that can change colors like a chameleon have shown great promise in the fields of visual sensing, intelligent wearing equipment and others. However, how to improve the performances of photonic elastomers to avoid the inconsistency of color caused by different observation angles remains a major challenge in this field. Recently, Professor Zhu Jintao and Professor Zhang Lianbin at Huazhong University of Science and Technology have made significant contributions to the field of responsive photonic materials, especially in the field of self-healing photonic crystal elastomers. This paper briefly reviews their recent progress in the area of responsive photonic materials. [ABSTRACT FROM AUTHOR]

A rapid and cost-effective lithographic method, polymer blend lithography (PBL), is reported to produce patterned self-assembled monolayers (SAM) on solid substrates featuring two or three different chemical functionalities. For the pattern generation we use the phase separation of two immiscible polymers in a blend solution during a spin-coating process. By controlling the spin-coating parameters and conditions, including the ambient atmosphere (humidity), the molar mass of the polystyrene (PS) and poly(methyl methacrylate) (PMMA), and the mass ratio between the two polymers in the blend solution, the formation of a purely lateral morphology (PS islands standing on the substrate while isolated in the PMMA matrix) can be reproducibly induced. Either of the formed phases (PS or PMMA) can be selectively dissolved afterwards, and the remaining phase can be used as a lift-off mask for the formation of a nanopatterned functional silane monolayer. This “monolayer copy” of the polymer phase morphology has a topographic contrast of about 1.3 nm. A demonstration of tuning of the PS island diameter is given by changing the molar mass of PS. Moreover, polymer blend lithography can provide the possibility of fabricating a surface with three different chemical components: This is demonstrated by inducing breath figures (evaporated condensed entity) at higher humidity during the spin-coating process. Here we demonstrate the formation of a lateral pattern consisting of regions covered with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) and (3-aminopropyl)triethoxysilane (APTES), and at the same time featuring regions of bare SiOx. The patterning process could be applied even on meter-sized substrates with various functional SAM molecules, making this process suitable for the rapid preparation of quasi two-dimensional nanopatterned functional substrates, e.g., for the template-controlled growth of ZnO nanostructures .

The corrosion protection abilities of modified copper in 2-[((Z)-1-{6- [(2-sulfanylphenyl)ethanimidoyl]-2-pyridyl}ethylidene) amino]-1- benzenthiol solution containing TiO2 nanoparticles were evaluated by Tafel polarization and impedance spectroscopy in 3.5% sodium chloride solution. The samples were characterized by energy dispersive X-ray (EDX) and scanning electron microscopy (SEM). The electrochemical results indicated corrosion resistance of this coating depends on the concentration of TiO2 nanoparticles and assembling time at this solution. After immersing copper for 10 min in Schiff base solution containing 150 mg L-1 nanoparticles, the coating was able to protect the copper against corrosion about 97%. Results indicated high ability of coating at high temperature and immersing time in sodium chloride solution.

Self-assembled molecular films of two cobalt porphyrins with amine groups at different positions—(5,10,15,20-tetrakis-(2-aminophenyl) porphyrin-cobalt(II), [Co(II) (T(o-NH2)PP)] and (5,10,15,20-tetrakis-(4-aminophenyl) porphyrin-cobalt(II), [Co(II)(T(p-NH2)PP)]—were formed on a gold substrate. The functionalized surfaces were characterized using Raman spectroscopy, atomic force microscopy and electrochemical methods. Both modified gold surfaces completely mask the charge transfer of a [Fe(CN)6]3−/4− redox couple in solution, indicating the layer is highly resistive in behavior. Electrochemical impedance spectroscopy analyses revealed that the porphyrin film with amine groups at ortho positions shows a higher charge-transfer resistance with a better protective behavior compared to the para position modified surface. Raman, AFM and EIS data suggests that an ortho amine positioned molecule forms a more compact layer compared to the para-positioned molecule. This can be explained in terms of their orientation on the gold surface. [Co(II)(T(o-NH2)PP)] adopted a saddle shape orientation whereas [Co(II)(T(p-NH2)PP)] adopted a flat orientation on the gold surface. The porphyrin modified gold electrode catalyzes the oxygen reduction at lower potentials compared to the bare gold electrode. The shift in the overvoltage was higher in case of molecules with flat orientation compared to the saddle shaped oriented porphyrin molecules on the surface.

Self-assembly of 13 nm gold nanoparticles (AuNPs) engineered into 2D structures in solution using DNA tiles for their possible use for gene delivery and photothermal therapy is reported. The two different DNA tiles were constructed and the AuNPs coated with oligonucleotides possessing complementary sequence from the free ends were hybridized with the sticky ends of the tiles. The DNA tiles were bind to each other by mixing the tile structures without a heating and cooling step. The constructed nanostructures were 5 to 7 DNA tiles long since heat was not used to elongate them. When the DNA tiles were bound to the AuNPs, it was observed that AuNPs tend to stay in close proximity by filling the gaps between tiles. The stability of the constructed structures was tested against DNase, a DNA cleaving enzyme, for possible applications for gene delivery and photothermal therapy. It was found that the AuNP bound DNA tile structures resist the DNase cleavage up to eighty percent. Due to the presence of the AuNPs in the structure, the enzyme cannot bind to DNA sequences and this increases the DNA tile structures’ stability.

This study has examined the osteogenic and chondrogenic differentiation of human foetal femur-derived cells in 3-dimensional pellet cultures. After culture for 21-28 days in osteogenic media, the pellets acquired a unique configuration that consisted of an outer fibrous layer, an osteoid-like shell surrounding a cellular and cartilaginous region. This configuration is typical to the cross section of the foetal femurs at the same age and was not observed in pellets derived from adult human bone marrow stromal cells. Time course study showed that after 7-14 days, the cells of the inner cellular region were viable, proliferated rapidly, and were immuno-positive for c-myc, as well as for bone sialoprotein and type I collagen. After 21-28 days, the cells accumulated at the inner edge of the osteoid shell. The direction of osteoid formation thus differed from that of periosteal bone formation. Following micro-dissection of the human foetal femurs into epiphyses, bone cylinder and hypertrophic cartilage, epiphyseal chondrocytes and osteoblasts both gave rise to osteoid-shell forming cells. These studies demonstrate the developmental plasticity of human foetal skeletal and epiphyseal chondrocytes and suggest that the microenvironment modulates lineage commitment and matrix formation. Furthermore, this ex vivo model offers a new approach to delineate human bone development as well as a model with potential application for evaluation of therapeutic compounds for bone formation.

Remarkable progress has been made to date in the discovery of material binding peptides and their utilization in nanotechnology, which has brought new challenges and opportunities. Nowadays phage display is a versatile tool, important for the selection of ligands for proteins and peptides. This combinatorial approach has also been adapted over the past decade to select material-specific peptides. Screening and selection of such phage displayed material binding peptides has attracted great interest, in particular because of their use in nanotechnology. Phage display selected peptides are either synthesized independently or expressed on phage coat protein. Selected phage particles are subsequently utilized in the synthesis of nanoparticles, in the assembly of nanostructures on inorganic surfaces, and oriented protein immobilization as fusion partners of proteins. In this paper, we present an overview on the research conducted on this area. In this review we not only focus on the selection process, but also on molecular binding characterization and utilization of peptides as molecular linkers, molecular assemblers and material synthesizers.

The growth of molecular assemblies at room temperature on insulating surfaces is one of the main goals in the field of molecular electronics. Recently, the directed growth of porphyrin-based molecular wires on KBr(001) was presented. The molecule–surface interaction associated with a strong dipole moment of the molecules was sufficient to bind them to the surface; while a stabilization of the molecular assemblies was reached due to the intermolecular interaction by π–π binding. Here, we show that the atomic structure of the substrate can control the direction of the wires and consequently, complex molecular assemblies can be formed. The electronic decoupling of the molecules by one or two monolayers of KBr from the Cu(111) substrate is found to be insufficient to enable comparable growth conditions to bulk ionic materials.

Chitosan has been the subject of interest for its use as a polymeric drug carrier material in dosage form design due to its appealing properties such as biocompatibility, biodegradability, low toxicity and relatively low production cost from abundant natural sources. However, one drawback of using this natural polysaccharide in modified release dosage forms for oral administration is its fast dissolution rate in the stomach. Since chitosan is positively charged at low pH values (below its pKa value), it spontaneously associates with negatively charged polyions in solution to form polyelectrolyte complexes. These chitosan based polyelectrolyte complexes exhibit favourable physicochemical properties with preservation of chitosan’s biocompatible characteristics. These complexes are therefore good candidate excipient materials for the design of different types of dosage forms. It is the aim of this review to describe complexation of chitosan with selected natural and synthetic polyanions and to indicate some of the factors that influence the formation and stability of these polyelectrolyte complexes. Furthermore, recent investigations into the use of these complexes as excipients in drug delivery systems such as nano- and microparticles, beads, fibers, sponges and matrix type tablets are briefly described.

Inspired by nature, the synthesis of biohybrid nanocomposites containing inorganic nanoparticles (NPs) and biopolymers such as DNA and peptides as templates offers great potential for a wide range of applications. Using selective recognition schemes of 3D protein spaces for the assembly of magnetic nanocrystals is a challenge with great promise in the field of biomedicine and magnetic data storage. Here we apply the toroidal protein Hcp1 as an interparticle connector for the directed molecular assembly and ferrimagnetic coupling of biohybrid cobalt ferrite NP wires. The resulting biohybrid NP composites show bundles of nanofibers ranging from nano- to the microscale in length verified by TEM, EDX analysis and focused ion beam cut. Their magnetic characterization reveals an increase of the coercive field (+12%) reaching values of high-end Nd2Fe14B bulk magnets, enhanced saturation (+28%) and remanence magnetization (+38%) at 2 K compared to NPs lacking the protein connector. Thus, the combination of the nanoscale alignment of magnetic NPs with the molecular precision of the protein connectors leads to constructive addition of the magnetization reversal energy. This approach can be used to control magnetic properties for the design of materials with enhanced coercivity applicable for magnetic data storage, hyperthermia and theranostics. [ABSTRACT FROM AUTHOR]

Ternary complex system of amylose/whey protein/free fatty acid has attracted significant interest in food nutraceuticals or functional compounds in food delivery systems due to the well-known low toxicity, excellent biocompatibility, and solubility. Maize amylose, β-lactoglobulin, α-linoleic acid were self-assembled and characterized by the TEM. Then, in order to understand the mechanism of the self-assembling actions of such a ternary system (interaction among amylose, β-lactoglobulin and α-linoleic acid) deeply, all-atom molecular dynamics simulations were performed to analyze the self-assembling of the 3 components by the Gromacs software. An amylose segment of 55 glucose residues was used to form a 6-fold left-handed helix with 55 nm inner diameter and 135 nm outer diameter approximately and a length of 738 nm. A β-lactoglobulin peptide segment was used on the basis of the three-dimensional (3D) structure determined from an NMR (nuclear magnetic resonance) analysis. The PDB (protein data bank) file for α-linoleic acid was obtained from the Heterocompound Information Centre in Uppsala, Sweden. The glucose force field was chosen and all simulations for the amylose-like molecule were carried out using the glucose force field. The Gromacs 4.6.1 MD package (ScalaLife Competence Center, European Research Council) was used for the simulation. The MD simulations were performed using the leapfrog motion routine with a 2×10-15 s time step. A total of 250 000 000 simulation steps (for a total of 500 ns simulation time) were performed to assess the progression of the self-assembly process. The LINCS algorithm was used to constrain all bond lengths. In the simulation, the temperature was set at 100 °C, necessary for the initial formation of the nanoparticle. This was performed using the modified Berendsen thermocouple between the different groups with a relaxation time of 0.1 ps, and the pressure was maintained at 1.0×105 Pa using the Parrinello−Rahman coupling to a pressure bath via an isotropic coordinate scaling with a relaxation time of 2×10-12 s. Non-chemical bond interactions were handled using a neighboring grid cell cutoff scheme. Within a neighboring molecules list's cutoff distance of 0.9 nm in a short range, the interactions were evaluated at every time step based on a pair list. A short-range electrostatic cutoff radius of 0.9 nm and a long-range Van der Waals' cutoff radius of 1.4 nm were evaluated simultaneously with each list updating. The binding order of the 3 components could be obtained through the self-assembly snapshot diagram of ternary nanoparticles within 500 ns. The TEM images showed that ternary nanoparticles had a rod-like conformation, which could be confirmed by the snapshot at 500 ns of ternary system from molecular dynamic simulation. Further analyses of their gyration radius and solvent accessible surface area showed that the ternary nanoparticles were highly hydrosoluble, which indicated that the nanoparticles could significantly enhance the aqueous solubility of some hydrophobic nutraceuticals or functional compounds. It also indicated that the formation of the ternary nanoparticles was a thermodynamically spontaneous process among amylose, β-lactoglobulin and α-linoleic acid interaction through the free energy curved-surface map of the ternary nanoparticle. The present work provides insights into the mechanism of the atomic structures of aqueous soluble self-assembled nanoparticles and presents new perspective for the design of nutraceuticals delivery systems with desirable properties. [ABSTRACT FROM AUTHOR]

The underlying challenge of drug delivery is the safe, controlled transport of a supply of therapeutic agent to its intended location at its effective dose. New and expanding solutions to payload delivery are being discovered in the field of hydrogels. Hydrogels are highly hydrated polymer networks that vary greatly depending on the underlying molecular structure. The subgroup of hydrogels that will be the focus of this chapter is the β-hairpin peptide hydrogel. These peptide-based materials are formed through a molecular self-assembly mechanism that only occurs after desired triggering of intramolecular peptide folding. Once folded, the β-hairpins assemble intermolecularly into a nanofibrillar network. The physical properties of the hydrogel network and its peptide foundation result in advantageous material properties which can be used for multiple biomedical applications including drug delivery. As a shear thinning solid that is easily injectable, cytocompatible, customizable, and well characterized, β-hairpin hydrogels are an exciting candidate as a drug delivery vehicle. [ABSTRACT FROM AUTHOR]

ABSTRACT The structure and activity of proteins is the gold standard for functional polymeric materials. This highlight seeks to calibrate the reader with respect to recent attempts to mimic the various structural and functional traits of proteins using the techniques of modern polymer chemistry. From advances in sequence-controlled polymers (primary structure), to peptidomimetics, foldamers, single-chain nanoparticles (secondary and tertiary structure), accessing the various structural aspects of protein chemistry is a vibrant research area. Likewise, the properties and utility of proteins in applications such as catalysis and molecular recognition are being emulated in the laboratory to great effect. Rather than provide an exhaustive review on any one of these topics, this article seeks to highlight the common thread among them, encouraging discussion and collaboration that will result in the next generation of smart materials with advanced structure and function. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 191-206 [ABSTRACT FROM AUTHOR]

Poly(ethylene glycol) (PEG), a polymer with excellent biocompatibility, was widely used to form nanoparticles for drug delivery applications. In this paper, based on PEG, a series of pH-sensitive amphiphilic block star polymers of poly(ethylene glycol)-block-poly(ethoxy ethyl glycidyl ether) (PEG- b-PEEGE) with different hydrophobic length were synthesized by living anionic ring-opening polymerization method. The products were characterized using H NMR and gel permeation chromatography. These copolymers could self-assemble in aqueous solution to form micellar structure with controlled morphologies. Transmission electron microscopy showed that the nanoparticles are spherical or rodlike with different hydrophilic mass fractions. The pH response of polymeric aggregates from PEG- b-PEEGE was detected by fluorescence probe technique at different pH. A pH-dependent release behavior was observed and pH-responsiveness of PEG- b-PEEGE was affected by the hydrophobic block length. These results demonstrated that star-shaped polymers (PEG- b-PEEGE) are attractive candidates as anticancer drug delivery carriers. [ABSTRACT FROM AUTHOR]

Contaminant fate and transport studies and models include transport mechanisms for colloidal particles and dissolved ions which can be easily moved with water currents. However, mobilization of much larger contaminated granular particles (i.e., sand) in sediments have not been considered as a possible mechanism due to the relatively larger size of sand particles and their high bulk density. We conducted experiments to demonstrate that oil contaminated granular particles (which exhibit hydrophobic characteristics) can attach on gas bubbles to form granular shells and transfer from the sediment phase to the water column. The interactions and conditions necessary for the oil contaminated granular particles to self assemble as tightly packed granular shells on the gas bubbles which transfer from sediment phase to the water column were evaluated both experimentally and theoretically for South Louisiana crude oil and quartz sand particles. Analyses showed that buoyancy forces can be adequate to move the granular shell forming around the air bubbles if the bubble radius is above 0.001 mm for the sand particles with 0.28 mm diameter. Relatively high magnitude of the Hamaker constant for the oil film between sand and air (5.81 × 10 − 20 J for air-oil-sand) indicates that air bubbles have high affinity to attach on the oil film that is on the sand particles in comparison to attaching to the sand particles without the oil film in water (1.60 × 10 − 20 J for air-water-sand). The mobilization mechanism of the contaminated granular particles with gas bubbles can occur in natural environments resulting in transfer of granular particles from sediments to the water column. [ABSTRACT FROM AUTHOR]

Silk fibers spun by silkworms and spiders exhibit exceptional mechanical properties with a unique combination of strength, extensibility and toughness. In contrast, the mechanical properties of regenerated silk materials can be tuned through control of the fabrication process. Here we introduce a biomimetic, all-aqueous process, to obtain bulk regenerated silk-based materials for the fabrication of functionalized orthopedic devices. The silk materials generated in the process replicate the nano-scale structure of natural silk fibers and possess excellent mechanical properties. The biomimetic materials demonstrate excellent machinability, providing a path towards the fabrication of a new family of resorbable orthopedic devices where organic solvents are avoided, thus allowing functionalization with bioactive molecules to promote bone remodeling and integration. [ABSTRACT FROM AUTHOR]

Non-ionic poly( N -acryloylmorpholine) (PNAM)-decorated polystyrene (PS) particles were synthesized by polymerization-induced self-assembly (PISA) in emulsion, mediated by the reversible addition-fragmentation chain transfer (RAFT) technique, in a one-pot/two-step process. PNAM was first prepared by RAFT polymerization in water using 4-cyano-4-thiothiopropylsulfanyl pentanoic acid (CTPPA) as chain transfer agent. Chain extension of PNAM by a PS block was then accomplished by the polymerization of styrene in water. Spherical nanoparticles (number-average diameter < 60 nm) exclusively composed of well-defined PNAM- b -PS amphiphilic block copolymers (1.1 < Ð < 1.4) were successfully obtained under a broad range of conditions (PNAM number-average molar mass of 2000, 4000 and 8000 g mol −1 , and average polymerization degree of the PS block from 150 up to 1600). Mannuronan (ManA 17 )- and guluronan (GulA 20 )-decorated nanoparticles were further synthesized according to a similar PISA process. Glycuronan macromonomers carrying a methacrylate polymerizable group (ManA 17 MA or GulA 20 MA) were first copolymerized with N -acryloylmorpholine (NAM) under successful RAFT control using CTPPA. The resulting hydrophilic P(NAM- co -ManA 17 MA) and P(NAM- co -GulA 20 MA) macroRAFT agents were then used to polymerize styrene in water. Spherical glycuronan-decorated nanoparticles composed exclusively of amphiphilic block copolymers were successfully obtained for both glycuronan-based macroRAFT agents. [ABSTRACT FROM AUTHOR]

We review recent theoretical developments, which suggest that a set of shared principles underpin macroscopic quantum phenomena observed in high temperature superconducting materials, room temperature coherence in photosynthetic processes and the emergence of long-range order in biological structures. These systems are driven by dissipative systems, which lead to fractal assembly and a fractal network of charges (with associated quantum potentials) at the molecular scale. At critical levels of charge density and fractal dimension, individual quantum potentials merge to form a 'charged-induced' macroscopic quantum potential, which act as a structuring force dictating long-range order. Whilst the system is only partially coherent (i.e. only the bosonic fields are coherent), within these processes many of the phenomena associated with standard quantum theory are recovered, with macroscopic quantum potentials and associated forces having their equivalence in standard quantum mechanics. We establish a testable hypothesis that the development of structures analogous to those found in biological systems, which exhibit macroscopic quantum properties, should lead to increased critical temperatures in high temperature superconducting materials. If the theory is confirmed, it opens up a new, systematic, ab initio approach to the structural development of these types of materials. [ABSTRACT FROM AUTHOR]

In this study thin films of a rod-coil block copolymer (BCP) are deposited from different solvents and used as templates for atomic layer deposition (ALD) of ZnO. The BCP, P3HT-b-PEO, is known to self-organize into fiber-like phase-separated nanostructures, with central crystalline P3HT domains and outer amorphous PEO domains. The P3HT block in this study is short so that the size of the P3HT domains in the films is solvent insensitive. However, processing from poor PEO solvents results in thin PEO domains and good PEO solvents allow extended PEO chains and wide domains. The crystallinity of the P3HT-block and the affinity of the PEO-block to the ALD ZnO precursors lead to selective deposition of ZnO in the PEO domains. Therefore, the solvent-controlled morphology of the PEO domains in the BCP films can be translated to the size, distribution and morphology of the deposited ZnO. We show that films with swollen PEO domains have higher ZnO uptake compared to films with collapsed PEO chains. Furthermore, oriented PEO domains template oriented ZnO domains and wormlike morphologies direct wormlike ZnO nanostructures. Therefore, solvent selection is a toll to manipulate the BCP self-assembly and hence the ALD template and the morphology of the hybrid organic/inorganic film. [ABSTRACT FROM AUTHOR]

Transparent electrodes (TEs) have attracted significant scientific, technological, and commercial interest in recent years due to the broad and growing use of such devices in electro-optics, consumer products (touch-screens for example), solar cells, and others. Currently, almost all commercial TEs are fabricated through “top-down” approaches (primarily lithography-based techniques), with indium tin oxide (ITO) as the most common material employed. Several problems are encountered, however, in this field, including the cost and complexity of TE production using top-down technologies, the limited structural flexibility, high-cost of indium, and brittle nature and low transparency in the far-IR spectral region of ITO. Alternative routes based upon bottom-up processes, have recently emerged as viable alternatives for production of TEs. Bottom up technologies are based upon self-assembly of building blocks - atoms, molecules, or nanoparticles – generating thin patterned films that exhibit both electrical conductivity and optical transparency. In this Feature Article we discuss the recent progress in this active and exciting field, including bottom-up TE systems produced from carbon materials (carbon nanotubes, graphene, graphene-oxide), silver, gold, and other metals. The current hurdles encountered for broader use of bottom-up strategies along with their significant potential are analyzed. [ABSTRACT FROM AUTHOR]

The design and synthesis of model compounds that do not exist naturally is one of the important targets in modern coordination chemistry. Herein, an eighteen-membered honeycomb structure with equal numbers of MnII (s=5/2) and GdIII (s=7/2) metal centers has been prepared, for the first time, by using a hydrophobic force-directed self-assembling process. Due to the weakly coupled GdIII pairs, the magnetic properties are mainly determined by eight-membered chains in the experimentally considered temperature range. These [Mn4Gd4] 'finite-size' chains, albeit with large Hilbert space, can be fully resolved by the high-temperature series expansion and the powerful finite-temperature Lanczos method, which reveal that the exchange-couplings between the metal centers are antiferromagnetic and consistent with the magnetization measurement. Interestingly, from the surface-engineering point of view, the [Mn4Gd4] chains are 'precisely' assembled into a 2D honeycomb pattern, which is potentially desirable in the design of weakly coupled qubits. [ABSTRACT FROM AUTHOR]

Charge transport across novel DNA junctions has been studied for several decades. From early attempts to move charge across DNA double crossover junctions to recent studies on DNA three-way junctions and G4 motifs, it is becoming clear that efficient cross-junction charge migration requires strong base-to-base electronic coupling at the junction, facilitated by favorable pi-stacking. We review recent progress toward the goal of manipulating and controlling charge transport through DNA junctions. [ABSTRACT FROM AUTHOR]

The room-temperature solvent vapor annealing of polystyrene- b -polydimethylsiloxane (PS- b -PDMS) block copolymer films was studied in situ by grazing incidence small-angle X-ray scattering. Films of cylinder-forming PS- b -PDMS with molecular weight 16 kg/mol and 12.2 kg/mol, annealed under vapors of toluene:heptane with varying composition, exhibited swelling-ratio-dependent evolution of microdomain spacing and orientation. In a vapor made from a toluene:heptane 5:1 volumetric ratio liquid mixture, or from pure toluene, cylindrical microdomains reoriented from majority out-of-plane to in-plane during annealing, while drying led to shrinkage along the film normal and a large distortion of the hexagonal lattice of in-plane cylinders. Annealing under vapor from a toluene:heptane 1:5 volumetric ratio liquid produced a non-bulk lamellar structure in the 16 kg/mol PS- b -PDMS. [ABSTRACT FROM AUTHOR]

Self assembled hybrid polyelectrolyte complex (PEC) nanoparticles are prepared from cationically modified gelatin and sodium alginate (Alg) by electrostatic complexation between the polymers. Cationised gelatin (CG) is prepared by the reaction of gelatin with ethylenediamine. Structural changes in gelatin, after modification with ethylenediamine are investigated by XRD and 1 H NMR spectroscopy. Hybrid polyelectrolyte nanoparticles, labeled CG/Alg, are prepared by simple mixing of CG and Alg. CG/Alg complex shows spherical morphology as confirmed by scanning electron microscopy. These polyelectrolyte complex nanoparticles can be used for the encapsulation and delivery of natural antioxidant curcumin to carcinoma cells. CG/Alg nanoparticles show curcumin encapsulation efficiency of 69% and exhibit sustained release of curcumin in vitro . Anticancer activity of curcumin loaded CG/Alg nanoparticles towards MCF-7 cells is disclosed by MTT assay. Intracellular uptake of the drug encapsulated nanoparticles is confirmed by fluorescent imaging. [ABSTRACT FROM AUTHOR]

This study demonstrates the self-assembly of N- and C-terminal protected dipeptides Phe–Gly and Pro–Gly which were derived from amyloidogenic and elastomeric peptide sequences. These constituents afforded nanostructured supramolecular ensembles through various non-covalent interactions in the solid state which can be directly correlated with their fibrillation event in solution phase. Interestingly microscopic observations revealed that the amyloidogenic dipeptide constituents assembled into hollow tubular structures whereas the elastomeric dipeptide constituents assembled into the feather or sheet like structures. [ABSTRACT FROM AUTHOR]

Luminescent structures based on semiconductor quantum dots (QDs) are increasingly used in biomolecular assays, cell tracking systems, and in-vivo diagnostics devices. In this work we have carried out the functionalization of porous silicon (PSi) luminescent structures by a perfluorosilane (Perfluoro-octyltriethoxysilane, PFOS) self assembly. The PFOS surface binding (traced by X-ray photoelectron spectroscopy) and photoluminescence efficiency were analyzed on flat model PSi. Maximal photoluminescence intensity was obtained from PSi layers anodized at 110 mA/cm 2 . Resistance to hydroxylation was assayed in H 2 O 2 :ethanol solutions and evidenced by water contact angle (WCA) measurements. PFOS-functionalized PSi presented systematically higher WCA than untreated PSi. The PFOS functionalization was found to slightly improve the aging of the PSi particles in water giving rise to particles with longer luminescent life. Confirmation of PFOS binding to PSi particles was derived from FTIR spectra and the preservation of luminescence was observed by fluorescence microscopy. Such functionalization opens the possibility of promoting hydrophobic-hydrophobic interactions between biomolecules and fluorescent QD structures, which may enlarge their biomedical applications catalogue. [ABSTRACT FROM AUTHOR]

Discotic liquid crystals (DLCs) are considered promising materials for organo-electronic applications. Columnar alignment of DLCs leads to anisotropic charge transport with high charge carrier mobility. However, pure DLCs exhibit low intrinsic charge carrier density which limits bulk conductivity. This research studies the alignment and conductivity properties of small molecule triphenylene-based DLCs to develop hole transport layers for potential applications in organic semiconductor devices. Binary mixtures of homologous DLCs of the hexakis(n-alkyloxy)triphenylene series (HAT6 and HAT10) are formulated. Mesophase characteristics and columnar alignment of these mixtures are characterized using polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). Alignment, orientation and order of columnar packing in the mixtures is studied using X-ray diffraction (XRD) and grazing incidence wide angle X-ray scattering (GIWAXS) measurements. It is identified that binary mixture formation strongly effects the columnar alignment in solution processed films. Furthermore, to increase charge carrier density in the DLC films a strong electron acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) is added as a p-type dopant, followed by an extensive characterization of its doping effect. POM, DSC thermal scans, UV–visible spectroscopy, photo-luminescence spectroscopy (PL) and I-V measurements are utilized to characterize and establish the improvement of hole conduction in the doped films. It is observed that F4TCNQ-doped triphenylene DLC films exhibit two-fold increase in hole conductivity, making the materials highly relevant for charge transport applications. [ABSTRACT FROM AUTHOR]

Purpose: In a situation where a couch shift for patient positioning is not preferred or prohibited (e.g., MR-linac), segment aperture morphing (SAM) can address target dislocation and deformation. For IMRT/VMAT with flattening-filter-free (FFF) beams, however, SAM method would lead to an adverse translational dose effect due to the beam unflattening. Here the authors propose a new two-step process to address both the translational effect of FFF beams and the target deformation. Methods: The replanning method consists of an offline and an online step. The offline step is to create a series of preshifted-plans (PSPs) obtained by a so-called "warm start" optimization (starting optimization from the original plan, rather than from scratch) at a series of isocenter shifts. The PSPs all have the same number of segments with very similar shapes, since the warm start optimization only adjusts the MLC positions instead of regenerating them. In the online step, a new plan is obtained by picking the closest PSP or linearly interpolating the MLC positions and the monitor units of the closest PSPs for the shift determined from the image of the day. This two-step process is completely automated and almost instantaneous (no optimization or dose calculation needed). The previously developed SAM algorithm is then applied for daily deformation. The authors tested the method on sample prostate and pancreas cases. Results: The two-step interpolation method can account for the adverse dose effects from FFF beams, while SAM corrects for the target deformation. Plan interpolation method is effective in diminishing the unflat beam effect and may allow reducing the required number of PSPs. The whole process takes the same time as the previously reported SAM process (5-10 min). Conclusions: The new two-step method plus SAM can address both the translation effects of FFF beams and target deformation, and can be executed in full automation except the delineation of target contour required by the SAM process. [ABSTRACT FROM AUTHOR]

The synthesis of oligo(ethylene glycol) with biphenolic gallates as termini and their assembly to dimeric structures upon spiroborate formation are described. Complexation of these dimeric structures with alkali metal ions showed selectivity to lithium and potassium by tuning the length of the ethyleneoxy units. The methoxycarbonyl group on the dimeric compound could be manipulated in harsh conditions without destruction of the dimeric structure. [ABSTRACT FROM AUTHOR]