Combining rotary wet-spinning biofabrication and electro-mechanical stimulation for theproduction of functional myo-substitutes.

In this work, we present an innovative, high-throughput rotary wet-spinning biofabrication method for manufacturing cellularized constructs composed of highly-aligned hydrogel fibers. The platform is supported by an innovative microfluidic printing head (MPH) bearing a crosslinking bath microtank with a co-axial nozzle placed at the bottom of it for the immediate gelation of extruded core/shell fibers. After a thorough characterization and optimization of the new MPH and the fiber deposition parameters, we demonstrate the suitability of the proposed system for theengineering of functional myo-substitutes.

Molecular Precursor Routes for Ag-Based Metallic, Intermetallic, and Metal Sulfide Nanoparticles: Their Comparative ORR Activity Trend at Solid|Liquid and Liquid|Liquid Interfaces.

The electrochemical conversion of oxygen to water is a crucial process required for renewable energy production, whereas its first two-electron step produces a versatile chemical and oxidant─hydrogen peroxide. Improving performance and widening the limited selection of the potential catalysts for this reaction is a step toward the implementation of clean-energy technologies. As silver is known as one of the most effective catalysts of oxygen reduction reaction (ORR), we have designed a suitable molecular precursor pathway for the selective synthesis of metallic (Ag), intermetallic (AgSb), and binary or ternary metal sulfide (AgS and AgSbS) nanomaterials by judicious control of reaction conditions.

Tuning composition of CuCoS-NiCoS solid solutions solvent-less pyrolysis of molecular precursors for efficient supercapacitance and water splitting.

Mixed metal sulfides are increasingly being investigated because of their prospective applications for electrochemical energy storage and conversion. Their high electronic conductivity and high density of redox sites result in significant improvement of their electrochemical properties. Herein, the composition-dependent supercapacitive and water splitting performance of a series of NiCu CoS (0.

Colloidal synthesis of metal chalcogenide nanomaterials from metal-organic precursors and capping ligand effect on electrocatalytic performance: progress, challenges and future perspectives.

Renewable and sustainable functional nanomaterials, which can be employed in alternative green energy sources, are highly desirable. Transition metal chalcogenides are potential catalysts for processes resulting in energy generation and storage. In order to optimize their catalytic performance, high phase purity and precise control over shape and size are indispensable.

The Solvent Effect on H O Generation at Room Temperature Ionic Liquid|Water Interface.

H O is a versatile chemical and can be generated by the oxygen reduction reaction (ORR) in proton donor solution in molecular solvents or room temperature ionic liquids (IL). We investigated this reaction at interfaces formed by eleven hydrophobic ILs and acidic aqueous solution as a proton source with decamethylferrocene (DMFc) as an electron donor. H O is generated in colorimetrically detectable amounts in biphasic systems formed by alkyl imidazolium hexafluorophosphate or tetraalkylammonium bis(trifluoromethylsulfonyl)imide ionic liquids.

Noble Metal Nanoparticles in Pectin Matrix. Preparation, Film Formation, Property Analysis, and Application in Electrocatalysis.

Stable polymeric materials with embedded nano-objects, retaining their specific properties, are indispensable for the development of nanotechnology. Here, a method to obtain Pt, Pd, Au, and Ag nanoparticles (ca. 10 nm, independent of the metal) by the reduction of their ions in pectin, in the absence of additional reducing agents, is described.

Patterning Cu nanostructures tailored for CO reduction to electrooxidizable fuels and oxygen reduction in alkaline media.

Due to the limited availability of noble metal catalysts, such as platinum, palladium, or gold, their substitution by more abundant elements is highly advisable. Considerably challenging is the controlled and reproducible synthesis of stable non-noble metallic nanostructures with accessible active sites. Here, we report a method of preparation of bare (ligand-free) Cu nanostructures from polycrystalline metal in a controlled manner.

Boosting water oxidation layer-by-layer.

Electrocatalysis of water oxidation was achieved using fluorinated tin oxide (FTO) electrodes modified with layer-by-layer deposited films consisting of bilayers of negatively charged citrate-stabilized IrO2 NPs and positively charged poly(diallyldimethylammonium chloride) (PDDA) polymer. The IrO2 NP surface coverage can be fine-tuned by controlling the number of bilayers. The IrO2 NP films were amorphous, with the NPs therein being well-dispersed and retaining their as-synthesized shape and sizes.

Synthesis and characterization of porous carbon-MoS nanohybrid materials: electrocatalytic performance towards selected biomolecules.

Porous carbon nanohybrids are promising materials as high-performance electrodes for both sensing and energy conversion applications. This is mainly due to their high specific surface area and specific physicochemical properties. Here, new porous nanohybrid materials are developed based on exfoliated MoS nanopetals and either negatively charged phenylsulfonated carbon nanoparticles or positively charged sulfonamide functionalized carbon nanoparticles.

Voltammetric pH Nanosensor.

Nanoscale pH evaluation is a prerequisite for understanding the processes and phenomena occurring at solid-liquid, liquid-liquid, and liquid-gas interfaces, e.g., heterogeneous catalysis, extraction, partitioning, and corrosion.

Tailored gold nanostructure arrays as catalysts for oxygen reduction in alkaline media and a single molecule SERS platform.

Although plenty of functional nanomaterials are widely applied in science and technology, cost-efficient, controlled and reproducible fabrication of metallic nanostructures is a considerable challenge. Automated electrorefining by scanning electrochemical microscopy (SECM) provides an effective approach to circumvent some drawbacks of traditional homogeneous syntheses of nanoparticles, providing precise control over the amount, time and place of reactant delivery. The precursor is just a raw metal, which is the most economically viable source.

Catalysis at the room temperature ionic liquid|water interface: H2O2 generation.

H2O2 is produced at the interface between a room-temperature ionic liquid with decamethylferrocene as an electron donor and an acidic aqueous solution. The electron donor can be regenerated electrochemically.

Catalysis of water oxidation in acetonitrile by iridium oxide nanoparticles.

Water oxidation catalysed by iridium oxide nanoparticles (IrO NPs) in water-acetonitrile mixtures using [Ru(bpy)] as oxidant was studied as a function of the water content, the acidity of the reaction media and the catalyst concentration. It was observed that under acidic conditions (HClO) and at high water contents (80% (v/v)) the reaction is slow, but its rate increases as the water content decreases, reaching a maximum at approximately equimolar proportions (≈25% HO (v/v)). The results can be rationalized based on the structure of water in water-acetonitrile mixtures.

Facile and rapid synthesis of Pd nanodendrites for electrocatalysis and surface-enhanced Raman scattering applications.

Numerous properties from metal nanostructures can be tuned by controlling both their size and shape. In particular, the latter is extremely important because the type of crystalline surface affects the surface electronic density. This paper describes a simple approach to the synthesis of highly-structured, anisotropic palladium nanostructured dendrites.

Selective electrochemical detection of dopamine in a microfluidic channel on carbon nanoparticulate electrodes.

There is a continuous need for the construction of detection systems in microfluidic devices. In particular, electrochemical detection allows the separation of signals from the analyte and interfering substances in the potential domain. Here, a simple microfluidic device for the sensitive and selective determination of dopamine in the presence of interfering substances was constructed and tested.

Surprising acidity of hydrated lithium cations in organic solvents.

Lithium cations are shown to have a significant role in catalyzing oxygen and proton reduction along with S(N)1 reactions in biphasic systems. We propose that this catalytic effect is due to the surprising acidity of the hydrated cations; interactions between the cation and its surrounding solvation shell will make the constituent water molecules more acidic.

Functionalized carbon nanoparticles, blacks and soots as electron-transfer building blocks and conduits.

Functionalized carbon nanoparticles (or blacks) have promise as novel active high-surface-area electrode materials, as conduits for electrons to enzymes or connections through lipid films, or as nano-building blocks in electroanalysis. With previous applications of bare nanoblacks and composites mainly in electrochemical charge storage and as substrates in fuel cell devices, the full range of benefits of bare and functionalized carbon nanoparticles in assemblies and composite (bio)electrodes is still emerging. Carbon nanoparticles are readily surface-modified, functionalized, embedded, or assembled into nanostructures, employed in bioelectrochemical systems, and incorporated into novel electrochemical sensing devices.

Anomalous effect of flow rate on the electrochemical behavior at a liquid|liquid interface under microfluidic conditions.

We have investigated the oxidation of ferrocene at a flowing organic solvent|aqueous electrolyte|solid electrode junction in a microfluidic setup using cyclic voltammetry and fluorescent laser scanning confocal microscopy. At low flow rates the oxidation current decreases with increasing flow, contrary to the Levich equation, but at higher flow rates the current increases linearly with the cube root of the flow rate. This behavior is explained using a simple model postulating a smallest effective width of the three-phase junction, which after fitting to the data comes to be ca.

Self-powered biosensor for ascorbic acid with a Prussian blue electrochromic display.

We report on the development of a nanocarbon based anode for sensing of ascorbic acid (AA). The oxidation of AA on this anode occurs at a quite low overpotential which enables the anode to be connected to a biocathode to form an ascorbic acid/O2 biofuel cell that functions as a self-powered biosensor. In conjunction with a Prussian blue electrochromic display the anode can also work as a truly self-powered sensor.

Nitrogen doped graphene nanosheet supported platinum nanoparticles as high performance electrochemical homocysteine biosensors.

Functional carbon nanomaterials are significantly important for the development of high performance sensitive and selective electrochemical biosensors. In this study, graphene supported platinum nanoparticles (GN-PtNPs) and nitrogen doped graphene supported platinum nanoparticles (N-GN-PtNPs) were synthesized by a simple chemical reduction method and explored as high performance nanocatalyst supports, as well as doped nanocatalyst supports, toward electrochemical oxidation of homocysteine (HCY) for the first the time. Our studies demonstrate that N-doped graphene supported PtNPs show higher electrocatalytic activity for HCY with an experimental detection limit of 200 pM.

Sensitive sugar detection using 4-aminophenylboronic acid modified graphene.

A sensitive electrochemical active interface for sugar sensing based on the specific boronic acid-diol binding was established. The sensing matrix was formed by stirring a suspension of graphene oxide (GO) with 4-aminophenylboronic acid (APBA). The resulting composite consists of a water insoluble precipitate of reduced graphene oxide (rGO) with APBA incorporated into the rGO matrix.

Thiol-yne click reactions on alkynyl-dopamine-modified reduced graphene oxide.

The large-scale preparation of graphene is of great importance due to its potential applications in various fields. We report herein a simple method for the simultaneous exfoliation and reduction of graphene oxide (GO) to reduced GO (rGO) by using alkynyl-terminated dopamine as the reducing agent. The reaction was performed under mild conditions to yield rGO functionalized with the dopamine derivative.

Nanostructured α-Fe2O3 platform for the electrochemical sensing of folic acid.

α-Fe(2)O(3) nanofibers are synthesized by a simple and efficient electrospinning method and the selective determination of folic acid (FA) is demonstrated in the presence of an important physiological interferent, ascorbic acid (AA), using the α-Fe(2)O(3) nanofiber modified glassy carbon (GC) electrode at physiological pH. Bare GC electrode fails to determine the concentration of FA in the presence of a higher concentration of AA due to the surface fouling caused by the oxidized products of AA and FA. However, modification with α-Fe(2)O(3) nanofibers not only separates the voltammetric signals of AA and FA by 420 mV between AA and FA, but also enhances higher oxidation current.

Preparation of a responsive carbohydrate-coated biointerface based on graphene/azido-terminated tetrathiafulvalene nanohybrid material.

A one-step method for the reduction of graphene oxide (GO) to reduced graphene oxide (rGO) is reported taking advantage of the electron-donor properties of an azido-terminated tetrathiafulvalene (TTF-N(3)). The resulting graphene/TTF-N(3) nanohybrid material is characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) spectroscopy, and by electrical and electrochemical means. The accessibility of the azide function to chemoselective modification by any alkyne-terminated partner molecule via Cu(I)-catalyzed "click" chemistry is demonstrated.