Self‐(Un)rolling Biopolymer Microstructures: Rings,Tubules, and Helical Tubules from the Same Material

We have demonstrated the facile formation of reversible and fast self‐rolling biopolymer microstructures from sandwiched active–passive, silk‐on‐silk materials. Both experimental and modeling results confirmed that the shape of individual sheets effectively controls biaxial stresses within these sheets, which can self‐roll into distinct 3D structures including microscopic rings, tubules, and helical tubules. This is a unique example of tailoring self‐rolled 3D geometries through shape design without changing the inner morphology of active bimorph biomaterials. In contrast to traditional organic‐soluble synthetic materials, we utilized a biocompatible and biodegradable biopolymer that underwent a facile aqueous layer‐by‐layer (LbL) assembly process for the fabrication of 2D films. The resulting films can undergo reversible pH‐triggered rolling/unrolling, with a variety of 3D structures forming from biopolymer structures that have identical morphology and composition.     

Hair analysis for illicit drugs by using capillary zone electrophoresis-electrospray ionization-ion trap mass spectrometry

In forensic toxicology, hair analysis has become a well established analytical strategy to investigate retrospectively drug abuse histories. In this field, gas chromatography-mass spectrometry and high-performance liquid chromatography-mass spectrometry are currently used, often after preliminary screening with immunoassays. However, on the basis of previous applications to pharmaceutical analysis, capillary zone electrophoresis coupled to ion trap mass spectrometry looks also highly promising. The purpose of the present work was the development of a simple and rapid CZE-MS method for sensitive and quantitative determination of the main drugs of abuse and their metabolites (namely, 6-monoacetylmorphine, morphine, amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethampthetamine (MDMA), benzoylecgonine, ephedrine and cocaine) in human hair. Hair samples (100 mg) were washed, cut and incubated overnight in 0.1 M HCl at 45 degrees C, then neutralized with NaOH and extracted by a liquid-liquid extraction method. CZE separations were carried out in a 100 cm x 75 microm (I.D.) uncoated fused silica capillary. The separation buffer was composed of 25 mM ammonium formate, pH 9.5; the separation voltage was 15 kV. Electrokinetic injections were performed at 7 kV for 30 s under field amplified sample stacking conditions. ESI-ion trap MS detection was performed in the ESI positive ionization mode using the following conditions: capillary voltage 4 kV, nebulizer gas (nitrogen) pressure 3psi, source temperature 150 degrees C and drying gas (nitrogen) flow rate 8l/min. A sheath liquid, composed of isopropanol-water (50:50, v/v) with 0.5% formic acid, was delivered at a flow rate of 4 microl/min. The ion trap MS operated in a selected ion monitoring mode (SIM) of positive molecular ions for each drug/metabolite. Collision induced fragmentation was also possible. Nalorphine was used as internal standard. Under the described conditions, the separation of all compounds, except amphetamine/methamphetamine, MDA/MDMA and morphine/6-MAM was achieved in 20 min, with limits of detection lower than the most severe cut-offs adopted in hair analysis (i.e. 0.1 ng/mg). Linearity was assessed within drug concentration ranges from 0.025 to 5 ng of each analyte/mg of hair. Analytical precision was fairly acceptable with RSD's < or = 3.06% for migration times and < or = 22.47% for areas in real samples, in both intra-day and day-to-day experiments. On these grounds, the described method can be proposed for rapid, selective and accurate toxicological hair analysis for both clinical and forensic purposes.     

Effects of the nanofiller size and aspect ratio on the thermal and rheological behavior of PEG nanocomposites containing boehmites or hydrotalcites

Journal of Thermal Analysis and Calorimetry - In this work, polyethylene glycol nanocomposites containing different nanofillers (namely hydrotalcites or boehmites, at 5&nbsp;mass% loading) were...     

A novel palladium catalyst for the synthesis of hydrogen peroxide from carbon monoxide, water and oxygen

The synthesis of hydrogen peroxide from carbon monoxide, water and oxygen in a biphasic system using palladium complexes with bidentate nitrogen ligands as catalysts was investigated. After testing a series of phenanthroline derivatives, 2,9-dimethyl-4,7-diphenylphenanthroline (8) was selected as the most efficient ligand. The palladium complex with ligand 8 showed high stability and catalytic activity (turnover number up to 600 moles of hydrogen peroxide per mole of palladium per hour) and, on the basis of a preliminary study, carried out in continuous operation mode, it appears a promising catalyst for the development of an industrial process.     

Conversion of Organic Dyes into Pigments: Extraction of Flavonoids from Blackberries (Rubus ulmifolius) and Stabilization

The blackberry’s color is composed mainly of natural dyes called anthocyanins. Their color is red–purple, and they can be used as a natural colorant. Anthocyanins are flavonoids, which are products of plants, and their colors range from orange and red to various shades of blue, purple and green, according to pH. In this study, the chemical composition of an extract obtained from blackberries was defined by LC-ESI/LTQOrbitrap/MS in positive and negative ionization mode. Furthermore, we investigated the adsorption process of blackberry extract using several inorganic fillers, such as metakaolin, silica, Lipari pumice, white pozzolan and alumina. The pigments exhibit different colors as a function of their interactions with the fillers. The analysis of the absorption data allowed the estimation of the maximum adsorbing capacity of each individual filler tested. Through thermogravimetric measurements (TGA), the thermal stability and the real adsorption of the organic extract were determined.     

A Simple Strategy for Easily Assembling 3D Printed Miniaturized Cells Suitable for Simultaneous Electrochemical and Spectrophotometric Analyses

A rapid and user‐friendly approach is here presented for assembling smart and versatile platforms for simultaneous electrochemical and spectrophotometric measurements. They consist of an optically transparent pencil‐drawn electrochemical cell, including reference, counter and working carbon electrodes, assembled on flexible PVC supports, exploiting a commercial desktop digitally controlled plotter/cutter. This cell is installed on a U shaped 3D printed polylactic frame where a second transparent window consisting of an unmodified PVC layer was also applied. After optimization of the fabrication procedure, the electrochemical and optical characterization of the assembled miniaturized platforms was performed by using aqueous electrolytes and potassium hexacyanoferrate(II) as redox probe. These devices were then tested by a proof‐of‐concept direct and simultaneous electrochemical and spectrophotometric quantification of a commonly used food dye (Brilliant Blue, E‐133) in soft‐drinks and candies. Spectrophotometric and electrochemical determinations can be performed at the same time, providing simultaneous information and enabling a concomitant comparison and validation of the results obtained.     

Direct screening of herbal blends for new synthetic cannabinoids by MALDI‐TOF MS

Since 2004, a number of herbal blends containing different synthetic compounds mimicking the pharmacological activity of cannabinoids and displaying a high toxicological potential have appeared in the market. Their availability is mainly based on the so‐called “e‐commerce”, being sold as legal alternatives to cannabis and cannabis derivatives. Although highly selective, sensitive, accurate, and quantitative methods based on GC–MS and LC–MS are available, they lack simplicity, rapidity, versatility and throughput, which are required for product monitoring. In this context, matrix‐assisted laser desorption ionization‐time of flight mass spectrometry (MALDI‐TOF MS) offers a simple and rapid operation with high throughput. Thus, the aim of the present work was to develop a MALDI‐TOF MS method for the rapid qualitative direct analysis of herbal blend preparations for synthetic cannabinoids to be used as front screening of confiscated clandestine preparations. The sample preparation was limited to herbal blend leaves finely grinding in a mortar and loading onto the MALDI plate followed by addition of 2 µl of the matrix/surfactant mixture [α‐cyano‐4‐hydroxy‐cinnamic acid/cetyltrimethylammonium bromide (CTAB)]. After drying, the sample plate was introduced into the ion source for analysis. MALDI‐TOF conditions were as follows: mass spectra were analyzed in the range m/z 150–550 by averaging the data from 50 laser shots and using an accelerating voltage of 20 kV. The described method was successfully applied to the screening of 31 commercial herbal blends, previously analyzed by GC–MS. Among the samples analyzed, 21 contained synthetic cannabinoids (namely JWH‐018, JWH‐073, JWH‐081, JWH‐250, JWH‐210, JWH‐019, and AM‐694). All the results were in agreement with GC–MS, which was used as the reference technique. Copyright © 2012 John Wiley & Sons, Ltd.     

The Coordination of NiII and CuII Ions to the Polyhistidyl Motif of Hpn Protein: Is It as Strong as We Think?

Hpn, one of Helicobacter pylori′s nickel‐accessory proteins, is an amazingly peculiar protein: Almost half of its sequence consists of polyhistidyl (poly‐His) residues. Herein, we try to understand the origin of this naturally occurring sequence, thereby shedding some light on the bioinorganic chemistry of Hpn′s numerous poly‐His repeats. By using potentiometric, mass spectrometric, and various spectroscopic techniques, we studied the Ni^II‐ and Cu^II complexes of the wild‐type Ac‐THHHHYHGG‐NH₂ fragment of Hpn and of its six analogues, in which consecutive residues (His or Tyr) were replaced by Ala (Ala‐substitution or Ala‐scan approaches), thereby resulting in Ac‐TAHHHYHGG‐NH₂, Ac‐THAHHYHGG‐NH₂, Ac‐THHAHYHGG‐NH₂, Ac‐THHHAYHGG‐NH₂, Ac‐THHHHAHGG‐NH₂, and Ac‐THHHHYAGG‐NH₂ peptides. We found that the His4 residue is critical for both Ni^II‐ and Cu^II‐ion binding and the effectiveness of binding varies even if the substituted amino acid does not take part in the direct binding interactions.     

Direct screening of herbal blends for new synthetic cannabinoids by MALDI-TOF MS

Since 2004, a number of herbal blends containing different synthetic compounds mimicking the pharmacological activity of cannabinoids and displaying a high toxicological potential have appeared in the market. Their availability is mainly based on the so-called "e-commerce", being sold as legal alternatives to cannabis and cannabis derivatives. Although highly selective, sensitive, accurate, and quantitative methods based on GC-MS and LC-MS are available, they lack simplicity, rapidity, versatility and throughput, which are required for product monitoring. In this context, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) offers a simple and rapid operation with high throughput. Thus, the aim of the present work was to develop a MALDI-TOF MS method for the rapid qualitative direct analysis of herbal blend preparations for synthetic cannabinoids to be used as front screening of confiscated clandestine preparations. The sample preparation was limited to herbal blend leaves finely grinding in a mortar and loading onto the MALDI plate followed by addition of 2 μl of the matrix/surfactant mixture [α-cyano-4-hydroxy-cinnamic acid/cetyltrimethylammonium bromide (CTAB)]. After drying, the sample plate was introduced into the ion source for analysis. MALDI-TOF conditions were as follows: mass spectra were analyzed in the range m/z 150-550 by averaging the data from 50 laser shots and using an accelerating voltage of 20?kV. The described method was successfully applied to the screening of 31 commercial herbal blends, previously analyzed by GC-MS. Among the samples analyzed, 21 contained synthetic cannabinoids (namely JWH-018, JWH-073, JWH-081, JWH-250, JWH-210, JWH-019, and AM-694). All the results were in agreement with GC-MS, which was used as the reference technique.