Biomaterial Strategies for Immunomodulation

Strategies to enhance, suppress, or qualitatively shape the immune response are of importance for diverse biomedical applications, such as the development of new vaccines, treatments for autoimmune diseases and allergies, strategies for regenerative medicine, and immunotherapies for cancer. However, the intricate cellular and molecular signals regulating the immune system are major hurdles to predictably manipulating the immune response and developing safe and effective therapies. To meet this challenge, biomaterials are being developed that control how, where, and when immune cells are stimulated in vivo, and that can finely control their differentiation in vitro. We review recent advances in the field of biomaterials for immunomodulation, focusing particularly on designing biomaterials to provide controlled immunostimulation, targeting drugs and vaccines to lymphoid organs, and serving as scaffolds to organize immune cells and emulate lymphoid tissues. These ongoing efforts highlight the many ways in which biomaterials can be brought to bear to engineer the immune system.Bill & Melinda Gates FoundationUnited States. Army Research Office. Institute for Soldier Nanotechnologies (Contract W911NF-13-D-0001)Ragon Institute of MGH, MIT and HarvardCancer Research Institute (New York, N.Y.) (Irvington Postdoctoral Fellowship)National Institutes of Health (U.S.) (Awards AI104715, CA172164, CA174795, and AI095109

Synthesis and electrochemical study of CoNi2S4 as a novel cathode material in a primary Li thermal battery

The authors acknowledge support and contribution from AWE Plc for this work, and thank the STFC for neutron diffraction beam-time.In this work CoNi2S4 was investigated as a candidate cathode material for Li thermal batteries. The CoNi2S4 was synthesized by a solid state reaction at 550◦C in a sealed quartz tube. Neutron powder diffraction was utilized to confirm normal spinel structure up to 200◦C, however, there was cation disorder above this temperature. The electrochemical properties of the batteries were investigated at 500◦C by galvanostatic discharge to elucidate the mechanism and the products NiS, Co3S4 and Co9S8 of the discharge mechanism were confirmed using powder X-ray diffraction. CoNi2S4 exhibits two voltage plateaus vs Li13Si4 at 500◦C, one at 1.75 V and the second at 1.50 V. CoNi2S4 has an overall capacity of 318 mA h g−1 from OCV 2.58 V to 1.25 V vs Li13Si4 which is comparable to that of the well-known metal disulfidesPublisher PDFPeer reviewe

Zirconium trisulfide as a promising cathode material for Li primary thermal batteries

In this work ZrS3 has been synthesized by solid state reaction in a sealed quartz tube and investigated as a candidate cathode material in Li thermal batteries. The structure of ZrS3 before and after cell testing has been studied using powder X-ray diffraction. A new spinel related material, LiZr2S4, has been identified as the product of the electrochemical process, which can be indexed to a = 10.452(8) Å cubic unit cell. The electrochemical properties of the batteries were investigated at 500 °C against Li13Si4 by galvanostatic discharge and galvanostatic intermittent titration technique (GITT). In a thermal Li cell at 500 °C a single voltage plateau of 1.70 V at a current density of 11 mA/cm2 was achieved with capacity of 357 mA h g-1. Therefore ZrS3 material has some promise as a cathode for Li thermal batteries.Publisher PDFPeer reviewe

‘We’re passengers sailing in the same ship, but we have our own berths to sleep in’: Evaluating patient and public involvement within a regional research programme: An action research project informed by Normalisation Process Theory

© 2019 Keenan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: Patient and public involvement (PPI) is a requirement for UK health and social care research funding. Evidence for how best to implement PPI in research programmes, such as National Institute for Health Research (NIHR) Collaborations for Applied Health Research and Care (CLAHRCs), remains limited. This paper reports findings from an action research (AR) project called IMPRESS, which aims to strengthen PPI within CLAHRC East of England (EoE). IMPRESS combines AR with Normalisation Process Theory (NPT) to explore PPI within diverse case study projects, identifying actions to implement, test and refine to further embed PPI.Methods:We purposively selected CLAHRC EoE case study projects for in-depth analysis of PPI using NPT. Data were generated from project PPI documentation, semi-structured qualitative interviews with researchers and PPI contributors and focus groups. Transcripts and documents were subjected to abductive thematic analysis and triangulation within case. Systematic across case comparison of themes was undertaken with findings and implications refined through stakeholder consultation.Results:We interviewed 24 researchers and 13 PPI contributors and analysed 28 documents from 10 case studies. Three focus groups were held: two with researchers (n = 4 and n = 6) and one with PPI contributors (n = 5). Findings detail to what extent projects made sense of PPI, bought in to PPI, operationalised PPI and appraised it, thus identifying barriers and enablers to fully embedded PPI.Conclusion:Combining NPT with AR allows us to assess the embeddedness of PPI within projects and programme, to inform specific local action and report broader conceptual lessons for PPI knowledge and practice informing the development of an action framework for embedding PPI in research programmes. To embed PPI within similar programmes teams, professionals, disciplines and institutions should be recognised as variably networked into existing PPI support. Further focus and research is needed on sharing PPI learning and supporting innovation in PPI.Peer reviewedFinal Published versio

Effect of halide-mixing on tolerance factor and charge-carrier dynamics in (CH3NH3PbBr3-xClx) perovskites powders

The authors are highly thankful for the financial support of Higher Education Commission (HEC) Pakistan through the equipment/research grants (6976/Federal/NRPU/R&D/HEC/2017), (20-3071/NRPU/R&D/HEC/13). Author ZS acknowledges HEC for indigenous PhD Fellowship Phase-II, Batch-II, 2013, PIN 213-66018-2PS2-127 and International Research Support Initiative Programme (IRSIP). Author LKJ acknowledges support from a Marie Skłodowska-Curie Individual Fellowship (European Commission) (MCIF: No. 745776).This work demonstrates a route to making mixed halide perovskite powders at room temperature by the anti-solvent-assisted crystallization method. Although, mixed halide CH3NH3PbBr3−xClx perovskites have been prepared by different methods, however, to the best of our knowledge the anti-solvent-assisted crystallization method is employed here for the first time to prepare mixed halide CH3NH3PbBr3−xClx perovskite powders. Solution-processed methyl ammonium lead tribromide CH3NH3PbBr3 (x = 0) and different amounts of chloride (Cl) containing mixed halide perovskites (CH3NH3PbBr3−xClx) were prepared for compositions of x = 0.5, 1, 1.25, 1.75. It reveals that bulk CH3NH3PbBr3−xClx samples are highly crystalline and exists in pure single cubic phase with an increased tolerance factor as compared to pure CH3NH3PbBr3. The CH3NH3PbBr3 perovskite has space-group Pm-3 m and a cell parameter of 5.930 Å (volume = 206 Å). The synthesis route adopted here gives access to hybrid perovskites powders with high Cl content and hence enables the band gap to be precisely tuned over a range from 2.26 to 2.49 eV. The powder samples display the subtle shifts in the emission spectra and the photoluminescence kinetics exhibits a decrease in average lifetime by increasing the Cl contents due to the presence of trap states in the structures that encourage non-radiative recombination of charge carrier. Conventionally, the CH3NH3PbBr3-based inverted solar cell architecture is prepared via mixing of the CH3NH3Br and PbBr2 precursors. In contrast, herein, the precursor solutions are directly prepared from the CH3NH3PbBr3 powder and the active layer of the inverted perovskite solar cells are then spin coated using this solution. The high Voc value of the fabricated solar cells potentially makes it a promising candidate for tandem photovoltaic, photocatalytic water splitting, and semi-transparent photovoltaic applications.PostprintPostprintPeer reviewe

Time-resolved in-situ X-ray diffraction study of CaO and CaO:Ca3Al2O6 composite catalysts for biodiesel production

The authors would like to acknowledge Innovate UK (Project Nos. 103498 and 106037) and EPSRC (EP/K015540/1 and EP/P007821/1) for funding. This work was carried out with the support of the Diamond Light Source, instrument I12 (proposal EE20820).Alternative and sustainable waste sources are receiving increasing attention as they can be used to produce biofuels with a low carbon footprint. Waste fish oil is one such example and can be considered an abundant and sustainable waste source to produce biodiesel. Ultimately this could lead to fishing communities having their own "off-grid" source of fuel for boats and vehicles. At the industrial level biodiesel is currently produced by homogeneous catalysis because of the high catalyst activity and selectivity. In contrast, heterogeneous catalysis offers several advantages such as improved reusability, reduced waste and lower processing costs. Here we investigate the phase evolution of two heterogeneous catalysts, CaO and a Ca3Al2O6:CaO ('C3A:CaO') composite, under in-situ conditions for biodiesel production from fish oil. A new reactor was designed to monitor the evolution of the crystalline catalyst during the reaction using synchrotron powder X-ray diffraction (PXRD). The amount of calcium diglyceroxide (CaDG) began to increase rapidly after approximately 30 minutes, for both catalysts. This rapid increase in CaDG could be linked to ex-situ NMR studies which showed that the conversion of fish oil to biodiesel rapidly increased after 30 minutes. The key to the difference in activity of the two catalysts appears to be that the Ca3Al2O6:CaO composite maintains a high rate of calcium diglyceroxide formation for longer than CaO, although the initial formation rates and reaction kinetics are similar. Overall this specialised in-situ set-up has been shown to be suitable to monitor the phase evolution of heterogeneous crystalline catalysts during the triglycerides transesterification reaction, offering the opportunity to correlate the crystalline phases to activity, deactivation and stability.Publisher PDFPeer reviewe

Role of lattice distortion and A site cation in the phase transitions of methylammonium lead halide perovskites

The rapid increase in power conversion efficiencies of photovoltaic devices incorporating lead halide perovskites has resulted in intense interest in the cause of their excellent properties. In the present paper, resonant ultrasound spectroscopy has been used to determine the elastic and anelastic properties of CH3NH3PbX3(where X=Cl, Br, or I) and CD3ND3PbI3 perovskites in the 5–380 K temperature range. This is coupled with differential scanning calorimetry, variable temperature neutron powder diffraction, and variable temperature photoluminescence studies to provide insights into the underlying processes and structural instabilities in the crystal structure. By comparing measurements on CH3NH3PbI3 with the deuterated equivalent, it has been possible to distinguish processes which are related to the hydrogen bonding between the methylammonium cation and the perovskite framework. We observe that replacing hydrogen with deuterium has a significant impact on both the elastic and photophysical properties, which shows that hydrogen bonding plays a crucial role in the material performance. Temperature-dependent photoluminescence studies show that the light emission is unaffected by the tetragonal-orthorhombic phase transition, but a blueshift in the emission and a steep increase in photoluminescence quantum yield are seen at temperatures below 150 K. Finally, observations of peaks in acoustic loss occurring in CH3NH3PbCl3 have revealed freezing processes in the vicinity of ∼150−170K, with activation energies in the range of 300 to 650 meV. These processes are attributed to freezing of the motion of methylammonium cations, and could explain the changes in photoluminescence seen in CH3NH3PbI3 at the same temperature. © 2018 American Physical Society. This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at: https://doi.org/10.1103/PhysRevMaterials.2.06540

Probing the energy levels of perovskite solar cells via Kelvin probe and UV ambient pressure photoemission spectroscopy

This work was supported by the Engineering and Physical Sciences Research Council (grant codes EP/M506631/1, EP/ K015540/01, EP/K022237/1 and EP/M025330/1). IDWS and JTSI acknowledge Royal Society Wolfson research merit awards.The field of organo-lead halide perovskite solar cells has been rapidly growing since their discovery in 2009. State of the art devices are now achieving efficiencies comparable to much older technologies like silicon, while utilising simple manufacturing processes and starting materials. A key parameter to consider when optimising solar cell devices or when designing new materials is the position and effects of the energy levels in the materials. We present here a comprehensive study of the energy levels present in a common structure of perovskite solar cell using an advanced macroscopic Kelvin probe and UV air photoemission setup. By constructing a detailed map of the energy levels in the system we are able to predict the importance of each layer to the open circuit voltage of the solar cell, which we then back up through measurements of the surface photovoltage of the cell under white illumination. Our results demonstrate the effectiveness of air photoemission and Kelvin probe contact potential difference measurements as a method of identifying the factors contributing to the open circuit voltage in a solar cell, as well as being an excellent way of probing the physics of new materials.Publisher PDFPeer reviewe

Use of interplay between A-site non-stoichiometry and hydroxide doping to deliver novel proton-conducting perovskite oxides

Funding: UK Engineering and Physical Sciences Research Council (Grant Number(s): EP/R023522, EP/R023751, EP/L017008, EP/P007821, EP/L000202, EP/R029431); Diamond Light Source (Grant Number(s): SP17198-8); Rutherford Appleton Laboratory (Grant Number(s): RB1920629).The magnitude of ionic conductivity is known to depend upon both mobility and number of available carriers. For proton conductors, hydration is a key factor in determining the charge–carrier concentration in ABO3 perovskite oxides. Despite the high reported proton mobility of calcium titanate (CaTiO3), this titanate perovskite has thus far been regarded as a poor proton conductor due to the low hydration capability. Here, the enhanced proton conductivity of the defective calcium titanate Ca0.92TiO2.84(OH)0.16 prepared by replacing lattice oxygens with hydroxyl groups via a solvothermal route is shown. Conductivity measurements in a humidified Ar atmosphere reveal that, remarkably, this material exhibits one order of magnitude higher bulk conductivity (10−4 Scm−1 at 200 °C) than hydrated stoichiometric CaTiO3 prepared by traditional solid-state synthesis due to the higher concentration of protonic defects and variation in the crystal structure. The replacement of Ca2+ by Ni2+ in the Ca1−xTi1O3−2x(OH)2x, which mostly exsolve metallic Ni nanoparticles along orthorhombic (100) planes upon reduction, is also demonstrated. These results suggest a new strategy by tailoring the defect chemistry via hydration or cation doping followed by exsolution for targeted energy applications.Publisher PDFPeer reviewe

In situ thermal battery discharge using CoS2 as a cathode material

Authors thank AWE and the EPSRC (EP/K015540/1) for funding. JTSI acknowledges a Royal Society Wolfson Research Merit award. We thank the STFC for beam-time.Thermal batteries are an established primary battery technology and the most commonly used cathodes in these batteries are transition metal disulfides MS2 (where M = Co, Ni and Fe). However, understanding the evolution of crystalline phases upon battery discharge has been hindered due to the high temperature operation of these batteries. Here we report an experiment that simultaneously collects powder neutron diffraction and electrochemical data as the battery is discharged. Four regions are observed in the diffraction data and four different cobalt containing phases are observed. Multi-phase Rietveld refinement has been used to monitor the evolution of phases during discharge and this is linked to the battery discharge profile. A new discharge mechanism has been proposed which involves hexagonal CoS instead of Co3S4, and the increase in unit cell parameters on discharge suggests the formation of a sulfur deficient solid solution before transformation to Co9S8. This behavior seems reminiscent of that of NiS2 suggesting that the discharge mechanisms of transition metal disulfides may have more similarities than originally thought.Publisher PDFPeer reviewe