Supramolecular Sensing of a Chemical Warfare Agents Simulant by Functionalized Carbon Nanoparticles.

Real-time sensing of chemical warfare agents by optical sensors is today a crucial target to prevent terroristic attacks by chemical weapons. Here the synthesis, characterization and detection properties of a new sensor, based on covalently functionalized carbon nanoparticles, are reported. This nanosensor exploits noncovalent interactions, in particular hydrogen bonds, to detect DMMP, a simulant of nerve agents. The nanostructure of the sensor combined with the supramolecular sensing approach leads to high binding constant affinity, high selectivity and the possibility to reuse the sensor.

Optimization of ZnO Nanorods Growth on Polyetheresulfone Electrospun Mats to Promote Antibacterial Properties.

Zinc oxide (ZnO) nanorods grown by chemical bath deposition (CBD) on the surface of polyetheresulfone (PES) electrospun fibers confer antimicrobial properties to the obtained hybrid inorganic-polymeric PES/ZnO mats. In particular, a decrement of bacteria colony forming units (CFU) is observed for both negative (Escherichia coli) and positive (Staphylococcus aureus and Staphylococcus epidermidis) Grams. Since antimicrobial action is strictly related to the quantity of ZnO present on surface, a CBD process optimization is performed to achieve the best results in terms of coverage uniformity and reproducibility. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) provide morphological and compositional analysis of PES/ZnO mats while thermogravimetric analysis (TGA) is useful to assess the best process conditions to guarantee the higher amount of ZnO with respect to PES scaffold. Biocidal action is associated to Zn2+ ion leaching in solution, easily indicated by UV-Vis measurement of metallation of free porphyrin layers deposited on glass.

Supramolecular Detection of a Nerve Agent Simulant by Fluorescent Zn-Salen Oligomer Receptors.

We report on new Zn-Salen oligomer receptors able to recognize a nerve agent simulant, namely dimethyl methylphosphonate (DMMP), by a supramolecular approach. In particular, three Zn-Salen oligomers (Zn-Oligo-A, -B, and -C), differing by the length distribution, were obtained and characterized by NMR, Gel Permeation Chromatography (GPC), UV-Vis, and fluorescence spectroscopy. Furthermore, we investigated their recognition properties towards DMMP by using fluorescence measurements. We found that the recognition ability depends on the length of the oligomeric chain, and the Zn-Oligo-C shows a binding constant value higher than those already reported in literature for the DMMP detection.

Polyethersulfone Mats Functionalized with Porphyrin for Removal of Para-nitroaniline from Aqueous Solution.

The dispersion of para-nitroaniline (p-NA) in water poses a threat to the environment and human health. Therefore, the development of functional adsorbents to remove this harmful compound is crucial to the implementation of wastewater purification strategies, and electrospun mats represent a versatile and cost-effective class of materials that are useful for this application. In the present study, we tested the ability of some polyethersulfone (PES) nanofibers containing adsorbed porphyrin molecules to remove p-NA from water. The functional mats in this study were obtained by two different approaches based on fiber impregnation or doping. In particular, meso-tetraphenyl porphyrin (H2TPP) or zinc(II) meso-tetraphenyl porphyrin (ZnTPP) were immobilized on the surface of PES fiber mats by dip-coating or added to the PES electrospun solution to obtain porphyrin-doped PES mats. The presence of porphyrins on the fiber surfaces was confirmed by UV-Vis spectroscopy, fluorescence measurements, and XPS analysis. p-NA removal from water solutions was spectrophotometrically detected and evaluated.

Efficacy of gummy lozenges containing Erysimum as ancillary treatment in children with sore throat.

BACKGROUND: Sore throat frequently occurs in children aged between four and fifteen years and is often associated to inflammation of the upper respiratory tract mucosa. A reliable approach to limit the damage caused by inflammation and, therefore, to alleviate associated symptoms might be the protection of the mucosa. Aim of this study was to assess the efficacy and tolerability of a medical device, formulated as a gummy lozenge and containing a combination of natural functional components (Erysimum, aloe vera and Xilogel®) able to exert a barrier effect on the mucosa, as ancillary treatment in children with sore throat. METHODS: This was an observational, prospective, parallel-group, multiple-dose trial of a medical device given in association to standard pharmacological prescribed therapy with an open label comparison vs. standard pharmacological prescribed therapy alone. The outcome measures of the study were assessed at baseline and after three days of treatment. RESULTS: One hundred and twelve school children with sore throat symptoms were recruited for this study and 69 were assigned to the group taking the study product. At the end of the treatment a statistically higher reduction in Sore Throat Pain Intensity Score and Pharyngitis Symptom Score was observed in the group taking the medical device. Moreover, the treatment with the medical device is associated to a statistically significant higher improvement of Child's General Conditions. The pediatrician assessed the efficacy and tolerability of the product under study as good/very good in 91% and 94%, respectively, of treated children. The consumer satisfaction questionnaire revealed that most of the children taking the lozenge rated it very positively in regard to its flavor and easiness of administration. CONCLUSIONS: The medical device used in this study may represent a valid choice as an adjuvant treatment in children with sore throat associated to upper respiratory tract infection.

Sorting of Molecular Building Blocks from Solution to Surface.

We demonstrate that molecular gradients on an organic monolayer is formed by preferential binding of ruthenium complexes from solutions also containing equimolar amounts of isostructural osmium complexes. The monolayer consists of a nanometer-thick assembly of 1,3,5-tris(4-pyridylethenyl)benzene (TPEB) covalently attached to a silicon or metal-oxide surface. The molecular gradient of ruthenium and osmium complexes is orthogonal to the surface plane. This gradient propagates throughout the molecular assembly with thicknesses over 30 nm. Using other monolayers consisting of closely related organic molecules or metal complexes results in the formation of molecular assemblies having an homogeneous and equimolar distribution of ruthenium and osmium complexes. Spectroscopic and computational studies revealed that the geometry of the complexes and the electronic properties of their ligands are nearly identical. These subtle differences cause the isostructural osmium and ruthenium complexes to pack differently on modified surfaces as also demonstrated in crystals grown from solution. The different packing behavior, combined with the organic monolayer significantly contributes to the observed differences in chemical composition on the surface.

Conjugated Gold-Porphyrin Monolayers Assembled on Inorganic Surfaces.

Gold nanoparticles show important properties owing to their electronic structures. A limitation of some gold nanoparticles is that they either show surface plasmons or luminescence. The increase in size of the gold nanoparticles, and the appearance of the surface plasmons may result in the disappearance of luminescence. The aim of our study is the nanoscale assembly of Au nanoparticles on a monolayer of porphyrin molecules anchored to functionalized inorganic surfaces. This functional architecture not only exhibits a strong surface plasmon due to the gold nanoparticles, but also a strong luminescence signal from the porphyrin molecules. Finally we observed a long-range order in the Au nanoparticles conjugated to the porphyrin monolayer.

Nerve Gas Simulant Sensing by a Uranyl-Salen Monolayer Covalently Anchored on Quartz Substrates.

A uranyl complex monolayer that easily allows the optical detection of a nerve gas simulant, namely, dimethyl methylphosphonate, is reported. Both UV/Vis spectroscopy and photoelectron data confirm that the functional hybrid material coordinates a Lewis base by means of the P=O group, which interacts with the uranium equatorial site available for complexation.

Communication between Discrete Nanostructures Triggered by Fine Tuning of an External Stimulus.

The design of molecular architectures able to transfer mass to each other is a field of extreme importance. In the present study it is shown that two especially designed covalently assembled nanostructures can interchange Cu(2+) ions upon an external OH(-) trigger. The obtained solid interfaces are of interest for signaling, communication, memory storage and optical devices.

Solid nanoarchitecture--Cu(II) solution: dynamics of the chemical communication.

Molecular monolayers and similar nanoarchitectures represent a promising future of the nanotechnology. Many of these systems behave as stimuli responsive materials since they undergo readable changes upon external stimuli. Therefore, chemical communication between these systems and the surrounding environment is a field extremely important. In the present study we explored by optical read-out the chemical communication between a porphyrin monolayer covalently bound to a quartz substrate (hardware) and copper(II) ions (stimulus). Different physical states can be safely distinguished since the intensity of the Soret band (output) associated with a calculated distribution diagram provided the degree of porphyrin complexation and, therefore, of the state of the optically active system as a result of a solution mediated interfacial communication.

Red light-triggerable nanohybrids of graphene oxide, gold nanoparticles and thermo-responsive polymers for combined photothermia and drug release effects.

The development of multifunctional nanohybrid systems for combined photo-induced hyperthermia and drug release is a challenging topic in the research of advanced materials for application in the biomedical field. Here, we report the first example of a three-component red-light-responsive nanosystem consisting of graphene oxide, gold nanoparticles and poly-N-isopropylacrylamide (GO-Au-PNM). The GO-Au-PNM nanostructures were characterized by spectroscopic techniques and atomic force microscopy. They exhibited photothermal conversion effects at various wavelengths, lower critical solution temperature (LCST) behaviour, and curcumin (Curc) loading capacity. The formation of GO-Au-PNM/Curc adducts and photothermally controlled drug release, triggered by red-light excitation (680 nm), were demonstrated using spectroscopic techniques. Drug-polymer interaction and drug-release mechanism were well supported by modelling simulation calculations. The cellular uptake of GO-Au-PNM/Curc was imaged by confocal laser scanning microscopy. In vitro experiments revealed the excellent biocompatibility of the GO-Au-PNM that did not affect the viability of human cells.

One-Pot Synthesis of Luminescent and Photothermal Carbon Boron-Nitride Quantum Dots Exhibiting Cell Damage Protective Effects.

Zero-dimensional boron nitride quantum dots (BNQDs) are arousing interest for their versatile optical, chemical, and biochemical properties. Introducing carbon contents in BNQDs nanostructures is a great challenge to modulate their physicochemical properties. Among the carbon moieties, phenolic groups have attracted attention for their biochemical properties and phenol-containing nanomaterials are showing great promise for biomedical applications. Herein, the first example of direct synthesis of water dispersible BNQDs exposing phenolic and carboxylic groups is presented. The carbon-BNQDs are prepared in a single-step by solvent-assisted reaction of urea with boronic reagents and are characterized by optical absorption, luminescence, Raman, Fourier transform infrared and NMR spectroscopy, X-ray photoelectron spectroscopy, dynamic light scattering, and atomic force microscopy. The carbon-BNQDs exhibit nanodimension, stability, high photothermal conversion efficiency, pH-responsive luminescence and Z-potential. The potential of the carbon-BNQDs to provide photothermal materials in solid by embedding in agarose substrate is successfully investigated. The carbon-BNQDs exhibit biocompatibility on colorectal adenocarcinoma cells (Caco-2) and protective effects from chemical and oxidative stress on Caco-2, osteosarcoma (MG-63), and microglial (HMC-3) cells. Amplicon mRNA-seq analyses for the expression of 56 genes involve in oxidative-stress and inflammation are performed to evaluate the molecular events responsible for the cell protective effects of the carbon-BNQDs.

Synthesis and Unique Behaviors of High-Purity HEA Nanoparticles Using Femtosecond Laser Ablation.

High-entropy alloys (HEAs) are a class of metal alloys consisting of four or more molar equal or near-equal elements. HEA nanomaterials have garnered significant interest due to their wide range of applications, such as electrocatalysis, welding, and brazing. Their unique multi-principle high-entropy effect allows for the tailoring of the alloy composition to facilitate specific electrochemical reactions. This study focuses on the synthesis of high-purity HEA nanoparticles using the method of femtosecond laser ablation synthesis in liquid. The use of ultrashort energy pulses in femtosecond lasers enables uniform ablation of materials at significantly lower power levels compared to longer pulse or continuous pulse lasers. We investigate how various femtosecond laser parameters affect the morphology, phase, and other characteristics of the synthesized nanoparticles. An innovative aspect of our solution is its ability to rapidly generate multi-component nanoparticles with a high fidelity as the input multi-component target material at a significant yielding rate. Our research thus focuses on a novel synthesis of high-entropy alloying CuCoMn1.75NiFe0.25 nanoparticles. We explore the characterization and unique properties of the nanoparticles and consider their electrocatalytic applications, including high power density aluminum air batteries, as well as their efficacy in the oxygen reduction reaction (ORR). Additionally, we report a unique nanowire fabrication phenomenon achieved through nanojoining. The findings from this study shed light on the potential of femtosecond laser ablation synthesis in liquid (FLASiL) as a promising technique for producing high-purity HEA nanoparticles.

Composite molecular assemblies: nanoscale structural control and spectroelectrochemical diversity.

The controlled deposition of metal complexes from solution on inorganic surfaces offers access to functional materials that otherwise would be elusive. For such surface-confined interfaces to form, specific assembly sequences are often used. We show here that varying the assembly sequence of two well-defined and iso-structural osmium and ruthenium polypyridyl complexes results in interfaces with strikingly different spectroelectrochemical properties. Successive deposition of redox-active layers of osmium and ruthenium polypyridyl complexes, leads to self-propagating molecular assemblies (SPMAs) with distinct internal interfaces and individually addressable components. In contrast, the clear separation of these interfaces upon sequential deposition of these two complexes, results in charge trapping or electrochemical communication between the metal centers, as a function of layer thickness and applied assembly sequence. The SPMAs were characterized using a variety of techniques, including: UV­vis spectroscopy, spectroscopic ellipsometry, electrochemistry, synchrotron X-ray reflectivity, angle-resolved X-ray photoelectron spectroscopy, and spectroelectrochemistry. The combined data demonstrate that the sequence-dependent assembly is a decisive factor that influences and provides the material properties that are difficult to obtain otherwise.

Assembly of surface-confined homochiral helicates: chiral discrimination of DOPA and unidirectional charge transfer.

Surface-confined double-helical polymers are generated by dynamic covalent assembly with preservation of chirality, metal coordination environment, and oxidation state of the precursor complexes. This one-step procedure involves both in solution and solution-to-surface assembly and resulted in chiral interfaces where pairs of ligands are wrapped around arrays of metal ions. In-plane XRD experiments revealed the formation of a highly ordered structure along the substrate surface. The chirality of the surfaces is expressed by the selective recognition of 3,4-dihydroxyphenylalanine (DOPA). The CD measurements show a response of the Δ-polymer-modified quartz substrates toward D-DOPA, whereas no change was observed after treatment with L-DOPA. These coordination-based interfaces assembled on metal-oxide substrates in combination with a redox-probe, [Os(bpy)3](PF6)2, in solution can resemble the behavior of a rectifier.

Fascinating role of the number of f electrons in dipolar and octupolar contributions to quadratic hyperpolarizability of trinuclear lanthanides-biscopper Schiff base complexes.

The trinuclear [Ln(NO3)3(CuL)2] complexes (Ln = La, Ce, Sm, Eu and Er, L = N,N'-1,3-propylen-bis(salicylideniminato) have been investigated by a combination of HLS and EFISH techniques to evaluate both the dipolar and octupolar contributions to their significant quadratic hyperpolarizability and to confirm that f electrons may tune their second-order NLO response. In the complexes investigated, the major contribution to the total quadratic hyperpolarizability is largely controlled by the octupolar contribution, but the values of both ßEFISH and [parallel]ß(J=1)[parallel], that is the dipolar part, are significantly influenced by the number of f electrons, confirming that the unexpected polarizable character of f electrons may be the origin of such fascinating evidence.

Structural and electronic characterization of self-assembled molecular nanoarchitectures by X-ray photoelectron spectroscopy.

Molecular monolayers and similar nanoarchitectures are indicative of the promising future of nanotechnology. Therefore, many scientists recently devoted their efforts to the synthesis, characterization, and properties of mono- and multilayer-based systems. In this context, X-ray photoelectron spectroscopy is an important technique for the in-depth chemical and structural characterization of nanoscopic systems. In fact, it is a surface technique suitable for probing thicknesses of the same order of the photoelectron inelastic mean free paths (a few tens of ångströms) and allows one to immediately obtain qualitative and quantitative data, film thickness, surface coverage, molecule footprint, oxidation states, and presence of functional groups. Nevertheless, other techniques are important in obtaining a complete spectroscopic characterization of the investigated systems. Therefore, in the present review we report on X-ray photoelectron spectroscopy of self-assembled molecular mono- and multilayer materials including some examples on which other characterization techniques produced important results.

Chemical and Morphological Modifications Induced by Argon Plasma Treatments on Fluorinated Polybenzoxazole Films.

Fluorinated photodefinable polymers are widely employed as re-distribution layers in wafer-level packaging to produce microelectronic devices because of their suitable low dielectric constant and moisture absorption, high mechanical toughness, thermal conductivity and stability, and chemical inertness. Typically, fluorinated photodefinable polybenzoxazoles (F-PBOs) are the most used in this field. In the present work, we investigated by atomic force microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy the morphological and chemical modifications induced by Ar plasma treatments on F-PBO films. This process, used to remove surface contaminant species, as well as increase the polymeric surface roughness, to improve the adhesion to the other components during electronic packaging, is a crucial step during the manufacturing of some microelectronic devices. We found that argon plasma treatments determine the wanted drastic increase of the polymer surface roughness but, in the presence of a patterned silver layer on F-PBO, needed for the fabrication of electric contacts in microelectronic devices, also induce some unwanted formation of silver fluoride species.

Electro-Sorption of Hydrogen by Platinum, Palladium and Bimetallic Pt-Pd Nanoelectrode Arrays Synthesized by Pulsed Laser Ablation.

Sustainable and renewable production of hydrogen by water electrolysers is expected to be one of the most promising methods to satisfy the ever-growing demand for renewable energy production and storage. Hydrogen evolution reaction in alkaline electrolyte is still challenging due to its slow kinetic properties. This study proposes new nanoelectrode arrays for high Faradaic efficiency of the electro-sorption reaction of hydrogen in an alkaline electrolyte. A comparative study of the nanoelectrode arrays, consisting of platinum or palladium or bimetallic nanoparticles (NPs) Pt80Pd20 (wt.%), obtained by nanosecond pulsed laser ablation in aqueous environment, casted onto graphene paper, is proposed. The effects of thin films of perfluoro-sulfonic ionomer on the material morphology, nanoparticles dispersion, and electrochemical performance have been investigated. The NPs-GP systems have been characterized by field emission scanning electron microscopy, Rutherford backscattering spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge cycles. Faradaic efficiency up to 86.6% and hydrogen storage capacity up to 6 wt.% have been obtained by the Pt-ionomer and Pd/Pt80Pd20 systems, respectively.

3D Printing Manufacturing of Polydimethyl-Siloxane/Zinc Oxide Micro-Optofluidic Device for Two-Phase Flows Control.

Tailored ZnO surface functionalization was performed inside a polydimethyl-siloxane (PDMS) microchannel of a micro-optofluidic device (mofd) to modulate its surface hydrophobicity to develop a method for fine tuning the fluid dynamics inside a microchannel. The wetting behavior of the surface is of particular importance if two different phases are used for system operations. Therefore, the fluid dynamic behavior of two immiscible fluids, (i) air-water and (ii) air-glycerol/water in PDMS mofds and ZnO-PDMS mofds was investigated by using different experimental conditions. The results showed that air-glycerol/water fluid was always faster than air-water flow, despite the microchannel treatment: however, in the presence of ZnO microstructures, the velocity of the air-glycerol/water fluid decreased compared with that observed for the air-water fluid. This behavior was associated with the strong ability of glycerol to create an H-bond network with the exposed surface of the zinc oxide microparticles. The results presented in this paper allow an understanding of the role of ZnO functionalization, which allows control of the microfluidic two-phase flow using different liquids that undergo different chemical interactions with the surface chemical terminations of the microchannel. This chemical approach is proposed as a control strategy that is easily adaptable for any embedded micro-device.