Poddar A, Pyreddy S, Carraro F, Dhakal S, Rassell A, Field MR, Reddy TS, Falcaro P, Doherty CM, and Shukla R
Chemical communications (Cambridge, England) [Chem Commun (Camb)] 2020 Dec 21; Vol. 56 (98), pp. 15406-15409. Date of Electronic Publication: 2020 Nov 16.
Gene therapy is highly suited for prostate cancer (PC). Metal-organic-frameworks (MOFs) are potential gene delivery systems. Target-specific cytoplasmic and nuclear knockdown in host gene expression using ZIF-C is shown for the first time through RNAi and CRISPR/Cas9 based gene editing in PC cells. A green tea phytochemical coating enhances intracellular delivery.
Lau CH, Konstas K, Doherty CM, Smith SJD, Hou R, Wang H, Carta M, Yoon H, Park J, Freeman BD, Malpass-Evans R, Lasseuguette E, Ferrari MC, McKeown NB, and Hill MR
Nanoscale [Nanoscale] 2020 Aug 28; Vol. 12 (33), pp. 17405-17410.
Membranes are crucial to lowering the huge energy costs of chemical separations. Whilst some promising polymers demonstrate excellent transport properties, problems of plasticisation and physical aging due to mobile polymer chains, amongst others, prevent their exploitation in membranes for industrial separations. Here we reveal that molecular interactions between a polymer of intrinsic microporosity (PIM) matrix and a porous aromatic framework additive (PAF-1) can simultaneously address plasticisation and physical aging whilst also increasing gas transport selectivity. Extensive spectroscopic characterisation and control experiments involving two near-identical PIMs, one with methyl groups (PIM-EA(Me2)-TB) and one without (PIM-EA(H2)-TB), directly confirm the key molecular interaction as the adsoprtion of methyl groups from the PIM matrix into the nanopores of the PAF. This interaction reduced physical aging by 50%, suppressed polymer chain mobilities at high pressure and increased H2 selectivity over larger gases such as CH4 and N2.
Al-Masri D, Yunis R, Hollenkamp AF, Doherty CM, and Pringle JM
Physical chemistry chemical physics : PCCP [Phys Chem Chem Phys] 2020 Aug 24; Vol. 22 (32), pp. 18102-18113.
Ionic liquids and plastic crystals based on pyrrolidinium cations are recognised for their advantageous properties such as high conductivity, low viscosity, and good electrochemical and thermal stability. The pyrrolidinium ring can be substituted with symmetric or asymmetric alkyl chain substituents to form a range of ionic liquids or plastic crystals depending on the anion. However, reports into the use of branched alkyl chains and how this influences the material properties are limited. Here, we report the synthesis of six salts - ionic liquids and organic ionic plastic crystals - where the typically used linear propyl chain substituent is replaced by the branched alternative, isopropyl, to form the cation [C(i3)mpyr]+, in combination with six different anions: dicyanamide, (fluorosulfonyl)(trifluoromethanesulfonyl)imide, bis(trifluoromethanesulfonyl)imide, bis(fluorosulfonyl)imide, tetrafluoroborate and hexafluorophosphate. The thermal and transport properties of these salts are compared to those of the analogous N-propyl-N-methylpyrrolidinium and N,N-diethylpyrrolidinium-based salts. Finally, a high lithium salt content ionic liquid electrolyte based on the bis(fluorosulfonyl)imide salt was developed. This electrolyte showed high coulombic efficiencies of lithium plating/stripping and high lithium ion transference number, making it a strong candidate for use in lithium metal batteries.
The apicomplexan Toxoplasma gondii induces strong protective immunity dependent upon recognition by Toll-like receptors (TLR)11 and 12 operating in conjunction with MyD88 in the murine host. However, TLR11 and 12 proteins are not present in humans, inspiring us to investigate MyD88-independent pathways of resistance. Using bicistronic IL-12-YFP reporter mice on MyD88+/+ and MyD88-/- genetic backgrounds, we show that CD11c+MHCII+F4/80- dendritic cells, F4/80+ macrophages, and Ly6G+ neutrophils were the dominant cellular sources of IL-12 in both wild type and MyD88 deficient mice after parasite challenge. Parasite dense granule protein GRA24 induces p38 MAPK activation and subsequent IL-12 production in host macrophages. We show that Toxoplasma triggers an early and late p38 MAPK phosphorylation response in MyD88+/+ and MyD88-/- bone marrow-derived macrophages. Using the uracil auxotrophic Type I T. gondii strain cps1-1, we demonstrate that the late response does not require active parasite proliferation, but strictly depends upon GRA24. By i. p. inoculation with cps1-1 and cps1-1:Δgra24, we identified unique subsets of chemokines and cytokines that were up and downregulated by GRA24. Finally, we demonstrate that cps1-1 triggers a strong host-protective GRA24-dependent Th1 response in the absence of MyD88. Our data identify GRA24 as a major mediator of p38 MAPK activation, IL-12 induction and protective immunity that operates independently of the TLR/MyD88 cascade.
Yoon HW, Lee TH, Doherty CM, Choi TH, Roh JS, Kim HW, Cho YH, Do SH, Freeman BD, and Park HB
The journal of physical chemistry letters [J Phys Chem Lett] 2020 Mar 19; Vol. 11 (6), pp. 2356-2362. Date of Electronic Publication: 2020 Mar 10.
Graphene oxide (GO) is a promising 2D material for adsorbents and membranes, in particular, for the CO 2 separation process. However, CO 2 diffusion and sorption in GO and its layered structures are still not well understood because of its heterogeneous structure. Here we report CO 2 sorption in GO and its derivatives (e.g., reduced GO (rGO)) in powders and films. These CO 2 sorption behaviors reveal that GO is highly CO 2 -philic via complex CO 2 -functional-group-surface interactions, as compared with graphite and rGOs. Even in highly interlocked, lamellar GO films, CO 2 molecules above a certain threshold pressure can diffuse into GO interlayers, causing GO films to swell and leading to dramatic increases in CO 2 sorption. Intercalated water in GO interlayers can be removed by preferential CO 2 sorption without any changes in the GO chemical structure. This finding helps to explain the origin of CO 2 affinity with GO and has implications for preparing anhydrous GO assemblies for various applications.
Omidvar M, Nguyen H, Liang Huang, Doherty CM, Hill AJ, Stafford CM, Feng X, Swihart MT, and Lin H
ACS applied materials & interfaces [ACS Appl Mater Interfaces] 2019 Dec 18; Vol. 11 (50), pp. 47365-47372. Date of Electronic Publication: 2019 Dec 05.
Polymers with high permeability and strong size-sieving ability are needed for H 2 /CO 2 separation at temperatures ranging from 100 to 300 °C to enable an energy-efficient precombustion CO 2 capture process. However, such polymers usually suffer from a permeability/selectivity tradeoff, that is, polymers with high permeability tend to exhibit a weak size-sieving ability and thus low selectivity. Herein, we demonstrate that carbonization of a suitable polymer precursor (i.e., polybenzimidazole or PBI) generates microcavities (leading to high H 2 permeability) and ultramicroporous channels (leading to strong size-sieving ability and thus high H 2 /CO 2 selectivity). Specifically, carbonization of PBI at 900 °C (CMS@900) doubles H 2 permeability and increases H 2 /CO 2 selectivity from 14 to 80 at 150 °C. When tested with simulated syngas-containing equimolar H 2 and CO 2 in the presence of water vapor for 120 h, CMS@900 exhibits stable H 2 permeability of ≈36 barrer and H 2 /CO 2 selectivity of ≈53 at 150 °C, above Robeson's 2008 upper bound and demonstrating robustness against physical aging and CO 2 plasticization.
Yunis R, Hollenkamp AF, Forsyth C, Doherty CM, Al-Masri D, and Pringle JM
Physical chemistry chemical physics : PCCP [Phys Chem Chem Phys] 2019 Jun 21; Vol. 21 (23), pp. 12288-12300. Date of Electronic Publication: 2019 May 29.
The synthesis and characterisation of new solid-state electrolytes is a key step in advancing the development of safer and more reliable electrochemical energy storage technologies. Organic ionic plastic crystals (OIPCs) are an increasingly promising class of material for application in devices such as lithium or sodium metal batteries as they can support high ionic conductivity, with good electrochemical and thermal stability. However, the choice of OIPC-forming ions is still relatively limited. Furthermore, understanding of the influence of different cations and anions on the thermal, structural and transport properties of these materials is still in its infancy. Here we report the synthesis and in-depth characterisation of a range of new OIPCs utilising the hexamethylguanidinium cation ([HMG]) with five different anions. The thermal, structural, transport properties and free volume in the different salts have been investigated. The free volume within the salts has been investigated by positron annihilation lifetime spectroscopy, and the single crystal and powder X-ray diffraction analysis of [HMG] bis(trifluoromethanesulfonyl)imide ([TFSI]) in phase I and II, [HMG] hexafluorophosphate ([PF 6 ]) and [HMG] tetrafluoroborate ([HMG][BF 4 ]) are reported. The HMG cation can exhibit significant disorder, which is advantageous for plasticity and future use of these materials as high ionic conductivity matrices. The bis(fluorosulfonyl)imide salt, [HMG][FSI], is identified as particularly promising for use as an electrolyte, with good electrochemical stability and soft mechanical properties. The findings introduce a range of new materials to the solid-state electrolyte arena, while the insights into the physico-chemical relationships in these materials will be of importance for the future development and understanding of other ionic electrolytes.