Recent experiments on a small-angle/wide-angle X-ray scattering beam line at the ESRF

Recent results using a new combined small-angle/wide-angle X-ray scattering (SAXS/WAXS) beam line at the European Synchrotron Radiation Source (ESRF) will be presented. This beam line is specifically designed to be able to handle complicated sample environments required to perform time-resolved experiments mimicking processing conditions used in material science. Besides the attention that has been given to the interfacing of these sample environments to the beam line data acquisition system also the developments in detector technology will be discussed. The influence that a high count rate and low noise WAXS detector can have on the accuracy of experimental results in polymer crystallisation will be shown. It is shown that it is feasible to detect crystalline volume fractions as low as 10(-3)-10(-4) in polymeric systems

Optical biosensor for catechol determination based on laccase‐immobilized anionic polyamide 6 microparticles

This work presents the preparation, optimization, and testing of an enzymebased optical biosensor for catechol determination. The sensing area is attached to a glass support and contains: anionic polyamide 6 (PA6) porous microparticles supporting laccase from Trametes Versicolor, embedded in a Pebax® MH1657 polymer binder that contains the optical indicator dye 3-methyl-2-benzothiazolinone hydrazone (MBTH), responsible for the optical transduction. The catechol analyte, after its enzymatic oxidation, forms o-benzoquinone that can be detected by oxidative coupling with MBTH giving rise to a colored product. The latter can be quantified easuring the UV/VIS absorbance at 500 nm. The PA6 microparticles performed as useful laccase carriers reaching high immobilization yields of up to 99.8% and preserving the enzyme catalytic activity. This permitted the reparation of a new biosensor presenting a detection limit of 11 μM and responding linearly to up to 118 μM of catechol. Biosensor applicability was tested in spiked natural water samples from river and spring. The recovery rates observed were in the range of 97–108% that proves the good accuracy of the proposed biosensor.All authors gratefully acknowledge the financial support of the project TSSiPRO NORTE-01-0145-FEDER-000015, supported by the regional operation program NORTE2020, under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund, as well as the support by National Funds through Fundação para a Ciência e Tecnologia (FCT), project UID/CTM/50025/2019. Special thank is due to the ALBA synchrotron governance for financing our WAXS/SAXS experiments at NCD SWEET beamline in the framework of the approved pro posal ID 2018/022726. N. Dencheva is also grateful for the financial support of FCT in the frames of the strategic project UID/CTM/50025/2013 and the personal program contract CTTI-51/18-IPC. The authors gratefully acknowledge the support of Dr. Amélie Noel (Arkema, France) for providing a free sample of Pebax® MH 1657

Polymer-assisted biocatalysis: polyamide 4 microparticles as promising carriers of enzymatic function

This study reports a new strategy for enzyme immobilization based on passive immobilization in neat and magnetically responsive polyamide 4 (PA4) highly porous particles. The microsized particulate supports were synthesized by low-temperature activated anionic ring-opening polymerization. The enzyme of choice was laccase from Trametes versicolor and was immobilized by either adsorption on prefabricated PA4 microparticles (PA4@iL) or by physical in situ entrapment during the PA4 synthesis (PA4@eL). The surface topography of all PA4 particulate supports and laccase conjugates, as well as their chemical and physical structure, were studied by microscopic, spectral, thermal, and synchrotron WAXS/SAXS methods. The laccase content and activity in each conjugate were determined by complementary spectral and enzyme activity measurements. PA4@eL samples displayed >93% enzyme retention after five incubation cycles in an aqueous medium, and the PA4@iL series retained ca. 60% of the laccase. The newly synthesized PA4-laccase complexes were successfully used in dyestuff decolorization aiming at potential applications in effluent remediation. All of them displayed excellent decolorization of positively charged dyestuffs reaching ~100% in 15 min. With negative dyes after 24 h the decolorization reached 55% for PA4@iL and 85% for PA4@eL. A second consecutive decolorization test revealed only a 5–10% decrease in effectiveness indicating the reusability potential of the laccase-PA4 conjugates.The authors gratefully acknowledge the financial support of the project TSSiPRONORTE-01-0145-FEDER-000015, supported by the regional operation program NORTE2020, under the Portugal2020 Partnership Agreement, through the European Regional Development Fund, as well as the support byNational Funds throughFundação para a Ciência e Tecnologia(FCT), project UID/CTM/50025/2019. D.S. and I.G.wish to thank the Research Foundation of the State of New York for partial funding through Materials Network ofExcellence. N.D. is also grateful for the personal program-contract CTTI-51/18-IPC

Magnetically responsive PA6 microparticles with immobilized laccase show high catalytic efficiency in the enzymatic treatment of catechol

Herewith we report the first attempt towards non-covalent immobilization of Trametes versicolor laccase on neat and magnetically responsive highly porous polyamide 6 (PA6) microparticles and their application for catechol oxidation. Four polyamide supports, namely neat PA6 and such carrying Fe, phosphate-coated Fe and Fe3O4 cores were synthesized in suspension by activated anionic ring-opening polymerization (AAROP) of ε-caprolactam (ECL). Enzyme adsorption efficiency up to 92% was achieved in the immobilization process. All empty supports and PA6 laccase complexes were characterized by spectral and synchrotron WAXS/SAXS analyses. The activity of the immobilized laccase was evaluated using 2,2’-Azino-bis-(3- ethylbenzothiazoline-6-sulfonic acid (ABTS) and compared to the native enzyme. The PA6 laccase conjugates displayed up to 105% relative activity at room temperature, pH 4, 40 °C and 20 mM ionic strength (citrate buffer). The kinetic parameters of the ABTS oxidation were also determined. The reusability of the immobilized laccase-conjugates was proven for five consecutive oxidation cycles of catechol.The authors gratefully acknowledge the financial support of the project TSSiPRO NORTE01-0145-FEDER-000015, supported by the regional operation program NORTE2020, under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund, as well as the support by National Funds through Fundação para a Ciência e Tecnologia (FCT), project UID/CTM/50025/2019. D.G. and I.G. wish to thank the Research Foundation of the State of New York—Networks of Excellence and the McIntyre-Stennis program of the US Department of Agriculture for partial funding. N.D. is also grateful for the personal program-contract CTTI-51/18-IPC

Supramolecular tripodal Au(I) assemblies in water. Interactions with pyrene fluorescent probe

The synthesis of three gold(I) tripodal complexes derived from tripropargylamine and containing the water soluble phosphines PTA (1, 3,5-triaza-7-phosphaadamantane), DAPTA (3,7-diacetyl-1,3,7-triaza--phosphabicyclo[3.3.1]nonane) and TPPTS (triphenylphosfine-3,3',3''-trisulfonic acid trisodium salt) is here described. The three complexes are observed to give rise to the formation of supramolecular aggregates in water and very long fibers. This property has been analyzed by means of 1H-NMR spectroscopy at different concentrations and SAXS. The results point out the important role of the phosphine moieties as the main enthalpic or entropic contribution in the resulting Gibbs energy of aggregates formation. The tripodal structure of the three complexes together with the presence of gold(I) atoms make them ideal candidates to interact with hydrophobic molecules also in water. For this, the interaction with pyrene in this solvent has been evaluated with successful results in all three complexes. The highest association constant corresponds to 2 as the host. DFT studies indicates the location of pyrene in the tripodal cavity as the most stable conformation. The interaction with pyrene has been additionally studied within cholate hydrogel matrixes pointing out the stability of the resulting host:guest adducts in the different medium

Aggregation induced emission of a new naphthyridine-ethynyl-gold(I) complex as a potential tool for sensing guanosine nucleotides in aqueous media

A new organometallic alkynyl-gold(I) complex, capable of exhibiting Aggregation Induced Emission was designed and synthesized. The linear complex structure possesses a central Au(I) atom, bearing two axial ligands: (1) 1,3,5-Triaza-7-phosphaadamantane; and (2) 2- acetamido-7-ethynyl-1,8-naphthyridine. While the former accounts for its partial solubility in aqueous environment, the latter acts as a receptor unit for binding guanosine nucleotides and derivatives via multiple hydrogen bonding. At high concentrations, aggregation of the complex was observed by the formation of new absorption (λmax ~ 400 nm) and emission bands (550-700 nm). Formation of aggregates of ca. 60 nm diameter was confirmed with Small Angle X-Ray Scattering (SAXS). Disruption of the aggregates in the presence of guanosine derivatives resulted in a ratiometric signal with apparent association constants in the order of 105 M-1 and high sensitivity (around 63% signal change) which are, to the best of our knowledge, in line with the highest recorded for nucleotide sensing based on hydrogen bonding that are capable of working in water. Computational studies indicate the presence of additional hydrogen bonding interactions that account for the strong binding of the Au(I) complex to phosphorylated Guanosine nucleotides

The Importance of Free Fatty Chain Length on the Lipid Organization in the Long Periodicity Phase

The skin's barrier ability is an essential function for terrestrial survival, which is controlled by intercellular lipids within the stratum corneum (SC) layer. In this barrier, free fatty acids (FFAs) are an important lipid class. As seen in inflammatory skin diseases, when the lipid chain length is reduced, a reduction in the barrier's performance is observed. In this study, we have investigated the contributing effects of various FFA chain lengths on the lamellar phase, lateral packing. The repeat distance of the lamellar phase increased with FFA chain length (C20-C28), while shorter FFAs (C16 to C18) had the opposite behaviour. While the lateral packing was affected, the orthorhombic to hexagonal to fluid phase transitions were not affected by the FFA chain length. Porcine SC lipid composition mimicking model was then used to investigate the proportional effect of shorter FFA C16, up to 50% content of the total FFA mixture. At this level, no difference in the overall lamellar phases and lateral packing was observed, while a significant increase in the water permeability was detected. Our results demonstrate a FFA C16 threshold that must be exceeded before the structure and barrier function of the long periodicity phase (LPP) is affected. These results are important to understand the lipid behaviour in this unique LPP structure as well as for the understanding, treatment, and development of inflammatory skin conditions.Drug Delivery Technolog

Time and spatially resolved operando small-angle X-ray scattering measurements during injection moulding of plastics

We recently introduced the possibility of performing operando small-angle X-ray scattering measurements using a novel industrially relevant injection moulding system for plastics. We show that useful time-resolving measurements can be performed with a time-cycle of 1 s and highlight the possible steps to reduce this to 0.5 s. We show how we can use the transmission measurements to provide a time marker when plastic first enters the mould cavity in the region probed by the incident X-ray beam. We show the opportunities provided by this experimental stage mounted on the NCD-SWEET beamline at ALBA to probe the reproducibility of the injection moulding system on different scales. The design of the equipment allowed for the development of the structure and the morphology to be evaluated in different parts of mould cavity, and we evaluated any differences in a rectangular mould cavity. We identified future prospects for this equipment in terms of novel mould heating and cooling systems and the opportunities for quantitatively evaluating radical approaches to injection moulding technology.This work was financially supported by the Fundação para a Ciência e a Tecnologia FCT/MCTES (PIDDAC) through the following Projects: MIT-EXPL/TDI/0044/2021, UIDB/04044/2020; UIDP/04044/2020; Associate Laboratory ARISE LA/P/0112/2020; PAMI—ROTEIRO/0328/2013 (No. 022158); plus EcoPlast, Materiais compósitos eco-sustentáveis para substituição dos plásticos convencionais, ref POCI-01-0247-FEDER-069002; and INNOV-AM funded by National Agency of Innovation M.A. is grateful for the support received from the Ministerio de Ciencia, Innovación y Universidades of Spain, with the mobility program of the grant “Ayudas para contratos predoctorales para la formación de doctoresas 2019”.  Peer ReviewedPostprint (published version

High pressure and temperature spinning capillary cell for in-situ synchrotron X-ray powder diffraction

In situ research of materials under moderate pressures (hundreds of bar) is essential in many scientific fields. These range from gas sorption to chemical and biological processes. One industrially important discipline is the hydration of oil well cements. Existing capillary cells in this pressure range are static as they are easy to design and operate. This is convenient for the study of single-phase materials; however, powder diffraction quantitative analyses for multiphase systems cannot be performed accurately as a good powder average cannot be attained. Here, the design, construction and commissioning of a cost-effective spinning capillary cell for in situ powder X-ray diffraction is reported, for pressures currently up to 200 bar. The design addresses the importance of reducing the stress on the capillary by mechanically synchronizing the applied rotation power and alignment on both sides of the capillary while allowing the displacement of the supports needed to accommodate different capillaries sizes and to insert the sample within the tube. This cell can be utilized for multiple purposes allowing the introduction of gas or liquid from both ends of the capillary. The commissioning is reported for the hydration of a commercial oil well cement at 150 bar and 150°C. The quality of the resulting powder diffraction data has allowed in situ Rietveld quantitative phase analyses for a hydrating cement containing seven crystalline phases.The design, production and commissioning of this cell was carried out at the ALBA synchrotron as part of Edmundo Fraga’s PhD project. This work was financially supported by the Spanish Ministry of Economy and Competitiveness through Grants BIA2014-57658-C2-1-R and BIA2017-82391-R which are co-funded by FEDER. We are grateful to Prof. Angus Wilkinson, Georgia Institute of Technology Atlanta, for sharing his knowledge and details on the high pressure cell developed by his team. We also thank Dr. Marcus Paul, Dyckerhoff-Lengerich, Germany, for fruitful discussion on Oil Well Cements. The cell was commissioned at BL11-NCD-SWEET beamline