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Singleton W.G.,University of Bristol | Collins A.M.,Bristol Center for Functional Nanomaterials | Bienemann A.S.,University of Bristol | Killick-Cole C.L.,University of Bristol | And 6 more authors.
International Journal of Nanomedicine | Year: 2017

Background: The pan-histone deacetylase inhibitor panobinostat is a potential therapy for malignant glioma, but it is water insoluble and does not cross the blood–brain barrier when administered systemically. In this article, we describe the in vitro and in vivo efficacy of a novel water-soluble nano-micellar formulation of panobinostat designed for administration by convection enhanced delivery (CED). Materials and methods: The in vitro efficacy of panobinostat-loaded nano-micelles against rat F98, human U87-MG and M059K glioma cells and against patient-derived glioma stem cells was measured using a cell viability assay. Nano-micelle distribution in rat brain was analyzed following acute CED using rhodamine-labeled nano-micelles, and toxicity was assayed using immunofluorescent microscopy and synaptophysin enzyme-linked immunosorbent assay. We compared the survival of the bioluminescent syngenic F98/Fischer344 rat glioblastoma model treated by acute CED of panobinostat-loaded nano-micelles with that of untreated and vehicle-only-treated controls. Results: Nano-micellar panobinostat is cytotoxic to rat and human glioma cells in vitro in a dose-dependent manner following short-time exposure to drug. Fluorescent rhodamine-labelled nano-micelles distribute with a volume of infusion/volume of distribution (Vi/Vd) ratio of four and five respectively after administration by CED. Administration was not associated with any toxicity when compared to controls. CED of panobinostat-loaded nano-micelles was associated with significantly improved survival when compared to controls (n=8 per group; log-rank test, P<0.001). One hundred percent of treated animals survived the 60-day experimental period and had tumour response on post-mortem histological examination. Conclusion: CED of nano-micellar panobinostat represents a potential novel therapeutic option for malignant glioma and warrants translation into the clinic. © 2017 Singleton et al.

Rios de Anda I.,University of Bristol | Rios de Anda I.,Bristol Center for Functional Nanomaterials | Statt A.,University of Bristol | Statt A.,Johannes Gutenberg University Mainz | And 3 more authors.
Contributions to Plasma Physics | Year: 2015

Charged colloids can behave as Yukawa systems, with similar phase behaviour. Using particle-resolved studies, we consider a system with an unusually long Debye screening length which forms crystals at low colloid volume fraction ϕ ≈ 0.01. We quantitatively compare this system with the Yukawa model and find that its freezing point is compatible with the theoretical prediction but that the crystal polymorph is not always that expected. In particular we find body-centred cubic crystals where face-centred cubic crystals are expected. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kumarakuru H.,University of Bristol | Kumarakuru H.,Nelson Mandela Metropolitan University | Cherns D.,University of Bristol | Collins A.M.,Bristol Center for Functional Nanomaterials
Ceramics International | Year: 2014

The structure and electrical properties of nanostructured Al-doped ZnO (AZO)/ZnO bilayers grown as potential solar cell electrodes by pulsed laser deposition on (0001) sapphire substrates are investigated. Transmission and scanning electron microscopy and X-ray diffraction show a narrow temperature window around 350-450 °C where nanostructures are formed. 2-D mapping of electrical conductivity by tunnelling atomic force microscopy showed that these nanostructures provided low resistance pathways, but that the overall film resistivity increased for substrate temperatures above 350 °C. The reasons for this are discussed. © 2014 Elsevier Ltd and Techna Group S.r.l.

Zhang Q.,University of Bristol | Zhang Q.,Xi'an Jiaotong University | Celorrio V.,University of Bristol | Bradley K.,University of Bristol | And 5 more authors.
Journal of Physical Chemistry C | Year: 2014

Correlations between the population of deep trap states in an array of TiO2 nanotubes (NT) and the dynamic photocurrent responses under supra-band-gap illumination are investigated. Ordered arrays of TiO2 NT of 10 μm length, 125 nm inner diameter, and 12 nm wall thickness featuring strong anatase character were obtained by anodization of Ti in ethylene glycol solution containing NH4F. Cyclic voltammograms at pH 10 show the characteristic responses for nanostructured TiO2 electrodes, in particular a sharp cathodic peak as the electron density in the film increases. These responses are associated with the population of deep trap states with an average value of 5 × 104 electrons per NT. Dynamic photocurrent measurements clearly show that the characteristic rise time of the photocurrent increases as the potential is increased above the onset region for charging deep trap states. At potentials in which deep trap states are fully depopulated in the dark, photocurrent rise time approaches values just below 1 s, which is more than 3 orders of magnitude slower than the estimated RC time constant. The occupancy of the deep trap states under photostationary conditions is a fraction of the density of states estimated from voltammetric responses. These findings are discussed in the context of current views about trap states in high surface area TiO2 electrodes. © 2014 American Chemical Society.

Eloi J.-C.,H H Wills Physics Laboratory | Okuda M.,H H Wills Physics Laboratory | Correia Carreira S.,H H Wills Physics Laboratory | Correia Carreira S.,Bristol Center for Functional Nanomaterials | And 3 more authors.
Journal of Physics Condensed Matter | Year: 2014

Isothermal magnetic relaxation measurements are widely used to probe energy barriers in systems of magnetic nanoparticles. Here we show that the result of such an experiment can differ greatly for aligned and randomly oriented nanoparticles. For randomly oriented cobalt-doped magnetite nanoparticles we observe a prominent low-energy tail in the energy barrier distribution that is greatly attenuated when the particles are magnetically aligned. Monte Carlo simulations show that this behaviour arises for nanoparticles with both cubic and uniaxial magnetic anisotropy energy terms even though for cubic or uniaxial anisotropy alone the energy barrier distribution is independent of nanoparticle orientation. © 2014 IOP Publishing Ltd.

Squires A.M.,University of Reading | Hallett J.E.,Bristol Center for Functional Nanomaterials | Hallett J.E.,University of Bristol | Beddoes C.M.,Bristol Center for Functional Nanomaterials | And 6 more authors.
Langmuir | Year: 2013

We demonstrate a method by which we can produce an oriented film of an inverse bicontinuous cubic phase (QII D) formed by the lipid monoolein (MO). By starting with the lipid as a disordered precursor (the L3 phase) in the presence of butanediol, we can obtain a film of the QII D phase showing a high degree of in-plane orientation by controlled dilution of the sample under shear within a linear flow cell. We demonstrate that the direction of orientation of the film is different from that found in the oriented bulk material that we have reported previously; therefore, we can now reproducibly form QII D samples oriented with either the [110] or the [100] axis aligned in the flow direction depending on the method of preparation. The deposition of MO as a film, via a moving fluid-air interface that leaves a coating of MO in the L3 phase on the capillary wall, leads to a sample in the [110] orientation. This contrasts with the bulk material that we have previously demonstrated to be oriented in the [100] direction, arising from flow producing an oriented bulk slug of material within the capillary tube. The bulk sample contains significant amounts of residual butanediol, which can be estimated from the lattice parameter of the QII D phase obtained. The sample orientation and lattice parameters are determined from synchrotron small-angle X-ray scattering patterns and confirmed by simulations. This has potential applications in the production of template materials and the growth of protein crystals for crystallography as well as deepening our understanding of the mechanisms underlying the behavior of lyotropic liquid-crystal phases. © 2013 American Chemical Society.

Beddoes C.M.,University of Bristol | Beddoes C.M.,Bristol Center for Functional Nanomaterials | Berge J.,University of Bristol | Bartenstein J.E.,University of Bristol | And 4 more authors.
Soft Matter | Year: 2016

Using high pressure small angle X-ray scattering (HP-SAXS), we have studied monoolein (MO) mesophases at 18 wt% hydration in the presence of 10 nm silica nanoparticles (NPs) at NP-lipid number ratios (ν) of 1 × 10-6, 1 × 10-5 and 1 × 10-4 over the pressure range 1-2700 bar and temperature range 20-60 °C. In the absence of the silica NPs, the pressure-temperature (p-T) phase diagram of monoolein exhibited inverse bicontinuous cubic gyroid (QGII), lamellar alpha (Lα), and lamellar crystalline (Lc) phases. The addition of the NPs significantly altered the p-T phase diagram, changing the pressure (p) and the temperature (T) at which the transitions between these mesophases occurred. In particular, a strong NP concentration effect on the mesophase behaviour was observed. At low NP concentration, the p-T region pervaded by the QGII phase and the Lα-QGII mixture increased, and we attribute this behaviour to the NPs forming clusters at the mesophase domain boundaries, encouraging transition to the mesophase with a higher curvature. At high NP concentrations, the QGII phase was no longer observed in the p-T phase diagram. Instead, it was dominated by the lamellar (L) phases until the transition to a fluid isotropic (FI) phase at 60 °C at low pressure. We speculate that NPs formed aggregates with a "chain of pearls" structure at the mesophase domain boundaries, hindering transitions to the mesophases with higher curvatures. These observations were supported by small angle neutron scattering (SANS) and scanning electron microscopy (SEM). Our results have implications to nanocomposite materials and nanoparticle cellular entry where the interactions between NPs and organised lipid structures are an important consideration. © 2016 The Royal Society of Chemistry.

Hernandez L.A.,University of Santiago de Chile | Del Valle M.A.,University of Santiago de Chile | Diaz F.R.,University of Santiago de Chile | Fermin D.J.,Bristol Center for Functional Nanomaterials | Risbridger T.A.G.,Bristol Center for Functional Nanomaterials
Electrochimica Acta | Year: 2015

Abstract Poly(1-amino-9,10-anthraquinone) (P1AAQ) nanowires have been directly electro-synthesized on a steel electrode, previously modified with a thin film of poly(P1AAQ-co-o-phenylenediamine), via a SiO2 mesoporous template. Nanostructures obtainment was verified by electrochemical techniques and TEM. After template removal, it was corroborated that the nanowires, about 30 nm in diameter and 200 nm in length, were attached to the P1AAQ surface. The reproducibility of the method exhibited a standard deviation 3.357.10-6 for Pox(0.8 V) and 3.901.10-6 for Pred(0.003 V) and, in addition, the response remains stable over ten successive voltammetric cycles. Characterization was conducted utilizing electrochemical techniques and visualized by SEM micrographs. Thus, to the pioneering methodology for obtaining polymeric nanowires utilizing just electrochemical techniques, this modification is now added in order to assure the adhesion of the polymeric nanostructures to the electrode surface; the feasibility of use of the device in the varied applications that these materials hold, is therefore envisaged. © 2015 Elsevier Ltd. All Rights reserved.

Boston R.,Bristol Center for Functional Nanomaterials | Boston R.,University of Bristol | Carrington A.,University of Bristol | Walsh D.,University of Bristol | Hall S.R.,University of Bristol
CrystEngComm | Year: 2013

The cuprate superconductor YBa2Cu3O 7-δ (Y123) has been synthesised for the first time in a spherical morphology. The use of carboxymethyl-dextran in a pre-formed, spherical morphology enables not only the engineering of this new macromorphological motif, but also crystallochemical control of the superconductor at the nano-scale. © 2013 The Royal Society of Chemistry.

Hou B.,University of Bristol | Benito-Alifonso D.,University of Bristol | Kattan N.,Bristol Center for Functional Nanomaterials | Cherns D.,University of Bristol | And 2 more authors.
Chemistry - A European Journal | Year: 2013

In the beginning: Intermediate species generated in the synthesis of Cu2ZnSn(S,Se)4 nanoparticles (see figure) in oleylamine have been identified. The solvent plays a central role in the reaction mechanism, determining the composition of the nanostructures. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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