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Abdullah RM, Badran HA, Abul-Hail RC. Electrical, Thermal Lens and Optical Study of Fluorescein Film for Application As Organic Photovoltaic Devices. J Fluoresc 2024; 34:549-560. [PMID: 37306839 DOI: 10.1007/s10895-023-03299-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 06/05/2023] [Indexed: 06/13/2023]
Abstract
This article is devoted to the study of various dielectric and optoelectrical parameters nonlinear optic behaviors, thermal lens and self-diffraction parameters of Fluorescein (FLs) doped polymethyl methacrylate (PMMA) films. The films were prepared with 60 mM. These studies are based on the calculated values of refractive, absorption coefficient, energy gap, extinction coefficient and nonlinear Refraction index ( n 2 ) . The polymer films were prepared using the casting technique. All samples were previously investigated by UV-Vis-NIR spectrophotometric measurements and Optical microscopy SEM and ATM. Utilizing thermal lens spectrometry, an investigation of the thermo-optical characteristics as well as the nonlinear refractive index was carried out. In this method, a pump beam and a probe beam were brought into collinear alignment with one another. To determination the nonlinear Refraction index ( n 2 ) . High values of nonlinear refractive index predict a bright future for materials in optical applications. These results indicate that the new dye is a promising candidate for applications in nonlinear optical devices. Investigations were carried out on organic photovoltaic devices in addition to devices consisting of active layers with conducting polymer of PHPP:P3HT film and PHPP:P3HT/Fls. The methods of polymer and dyes synthesis are presented and their physical properties are given.
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Affiliation(s)
- Rajaa M Abdullah
- Department of Physics, College of Education for Pure Sciences, University of Basrah, Basrah, Iraq
- Department of Material Science, Polymer Research Centre, University of Basrah, Basrah, Iraq
| | - Hussain A Badran
- Department of Material Science, Polymer Research Centre, University of Basrah, Basrah, Iraq.
| | - Riyadh Ch Abul-Hail
- Department of Material Science, Polymer Research Centre, University of Basrah, Basrah, Iraq
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2
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da Costa Brito S, Pereira VAC, Prado ACF, Tobias TJ, Paris EC, Ferreira MD. Antimicrobial potential of linear low-density polyethylene food packaging with Ag nanoparticles in different carriers (Silica and Hydroxyapatite). J Microbiol Methods 2024; 217-218:106873. [PMID: 38128700 DOI: 10.1016/j.mimet.2023.106873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 11/26/2023] [Accepted: 12/07/2023] [Indexed: 12/23/2023]
Abstract
Silver nanoparticles incorporation into polymeric packaging aims to prevent microbiological contamination in food products, thus ensuring superior food safety and preservation. In this context, this study aimed to verify the antimicrobial efficacy of linear low-density polyethylene (LLDPE) films incorporated with silver nanoparticles (AgNPs) dispersed in silica (SiO2) and hydroxyapatite (HAP) carriers at different concentrations. AgNPs + carriers polymer films were characterized at 0.2, 0.4, and 0.6% concentrations using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission gun-scanning electron microscope (FEG-SEM), thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC), and migration in acidic and non-acidic simulants. Antimicrobial action was investigated on Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, and the Penicillium expansum and Fusarium solani fungi with antimicrobial activity by direct contact test and bacterial imaging by scanning electron microscopy. AgNPs addition to the LLDPE matrix did not interfere with the films' chemical and thermal properties and presented no significant migration to the external medium. For antimicrobial action, silver nanoparticles showed, in most concentrations, an inhibition percentage higher than 90% on all microorganisms studied, regardless of the carrier. However, a greater inhibitory action on S. aureus and between carriers was found, making hydroxyapatite more effective. The results indicated that nanostructured films with AgNPs + hydroxyapatite showed more promising antimicrobial action on microorganisms than AgNPs + silica, making hydroxyapatite with silver nanoparticle potentially useful in food packaging, improving safety and maintaining quality.
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Affiliation(s)
- Sabrina da Costa Brito
- Postgraduate Program in Food Science and Engineering, São Paulo State University "Julio de Mesquita Filho", Rod. Araraquara Jaú, Km 01, 14800-903 Araraquara, SP, Brazil; Embrapa Instrumentação, Rua XV de Novembro, 1452, 13560-970 São Carlos, SP, Brazil
| | - Vinicius Alex Cano Pereira
- Embrapa Instrumentação, Rua XV de Novembro, 1452, 13560-970 São Carlos, SP, Brazil; Biotechnology Graduate Program, Federal University of São Carlos, Rod. Washington Luís, Km 235 - C. P.676, 13.565-905 São Carlos, SP, Brazil
| | - Ana Carolina Figueiredo Prado
- Embrapa Instrumentação, Rua XV de Novembro, 1452, 13560-970 São Carlos, SP, Brazil; Postgraduate Program in Materials Science and Engineering, Federal University of São Carlos, Rod. Washington Luís, Km 235 - C. P.676, 13.565-905 São Carlos, SP, Brazil
| | - Thais Juliana Tobias
- Chemistry Graduate Program, University of Sao Paulo, Av. Trabalhador São-carlense, 400, 13.560-970 São Carlos, SP, Brazil
| | - Elaine Cristina Paris
- Embrapa Instrumentação, Rua XV de Novembro, 1452, 13560-970 São Carlos, SP, Brazil; Postgraduate Program in Chemistry, Federal University of São Carlos, Rod. Washington Luís, Km 235 - C. P.676, 13.565-905 São Carlos, SP, Brazil
| | - Marcos David Ferreira
- Postgraduate Program in Food Science and Engineering, São Paulo State University "Julio de Mesquita Filho", Rod. Araraquara Jaú, Km 01, 14800-903 Araraquara, SP, Brazil; Embrapa Instrumentação, Rua XV de Novembro, 1452, 13560-970 São Carlos, SP, Brazil.
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Khrebtov AA, Fedorenko EV, Beloliptsev AY, Mirochnik AG. Polymer films doped with boron difluoride ortho-hydroxydibenzoylmethanates: Solvatochromism and solvent-induced exciplex formation. Spectrochim Acta A Mol Biomol Spectrosc 2022; 267:120548. [PMID: 34742150 DOI: 10.1016/j.saa.2021.120548] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 09/23/2021] [Accepted: 10/24/2021] [Indexed: 06/13/2023]
Abstract
The spectral properties and solvatochromic behavior of boron difluoride ortho-hydroxydibenzoylmethanates in polymer matrices with different polarity (polystyrene, polyvinyl chloride, polycarbonate, poly(methyl methacrylate)) were investigated. The specific interaction of polystyrene, polycarbonate and poly(methyl methacrylate) with the investigated fluorophores was revealed. It was shown that the dyes are capable to form exciplexes with phenyl rings of polystyrene. The spectral properties of polystyrene films doped with boron difluoride ortho-hydroxydibenzoylmethanates, which were obtained by the pouring method, significantly depend on the solvent from which they were formed. This makes it possible to control the luminescence color of the films at the manufacturing stage.
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Affiliation(s)
- Aleksandr A Khrebtov
- Institute of Chemistry, Far-Eastern Branch of the Russian Academy of Sciences, Vladivostok 690022, Russian Federation; Far Eastern Federal University, Vladivostok 690091, Russian Federation.
| | - Elena V Fedorenko
- Institute of Chemistry, Far-Eastern Branch of the Russian Academy of Sciences, Vladivostok 690022, Russian Federation.
| | - Anton Yu Beloliptsev
- Institute of Chemistry, Far-Eastern Branch of the Russian Academy of Sciences, Vladivostok 690022, Russian Federation.
| | - Anatolii G Mirochnik
- Institute of Chemistry, Far-Eastern Branch of the Russian Academy of Sciences, Vladivostok 690022, Russian Federation.
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Boldrini B, Ostertag E, Rebner K, Oelkrug D. Exploring the hidden depth by confocal Raman experiments with variable objective aperture and magnification. Anal Bioanal Chem 2021; 413:7093-7106. [PMID: 34599394 PMCID: PMC8589783 DOI: 10.1007/s00216-021-03678-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/25/2021] [Accepted: 09/20/2021] [Indexed: 10/31/2022]
Abstract
The article analyzes experimentally and theoretically the influence of microscope parameters on the pinhole-assisted Raman depth profiles in uniform and composite refractive media. The main objective is the reliable mapping of deep sample regions. The easiest to interpret results are found with low magnification, low aperture, and small pinholes. Here, the intensities and shapes of the Raman signals are independent of the location of the emitter relative to the sample surface. Theoretically, the results can be well described with a simple analytical equation containing the axial depth resolution of the microscope and the position of the emitter. The lower determinable object size is limited to 2-4 μm. If sub-micrometer resolution is desired, high magnification, mostly combined with high aperture, becomes necessary. The signal intensities and shapes depend now in refractive media on the position relative to the sample surface. This aspect is investigated on a number of uniform and stacked polymer layers, 2-160 μm thick, with the best available transparency. The experimental depth profiles are numerically fitted with excellent accuracy by inserting a Gaussian excitation beam of variable waist and fill fraction through the focusing lens area, and by treating the Raman emission with geometric optics as spontaneous isotropic process through the lens and the variable pinhole, respectively. The intersectional area of these two solid angles yields the leading factor in understanding confocal (pinhole-assisted) Raman depth profiles. Spearfishing is a well-known example of the effects of refraction at the boundary between two index-mismatched media. The object Greal is seen, due to refraction, as Gvir from the angle β (without knowing the depth position). The real position is obtained under the angle α. In a microscope (see inset), index mismatch deforms the image point of Greal into an image line. The pinhole substantially reduces deformations and allows the determination of the position of the point emitter G. (Cartoon designed by Sofia Anker).
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Affiliation(s)
- Barbara Boldrini
- Process Analysis and Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany.
| | - Edwin Ostertag
- Process Analysis and Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany
| | - Karsten Rebner
- Process Analysis and Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany
| | - Dieter Oelkrug
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
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Cano-Vega MA, Deng M, Pinal R. Modular solid dosage form design - Application to pH-independent release of a weak-base API. Int J Pharm 2021; 601:120518. [PMID: 33775729 DOI: 10.1016/j.ijpharm.2021.120518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/19/2021] [Accepted: 03/21/2021] [Indexed: 11/25/2022]
Abstract
A novel approach to solid dosage form design is investigated, whereby instead of blending the ingredients and subsequently compacting the mixture, the dosage form is made by assembling prefabricated components, each with a specific function. The approach was used to formulate a weak-base API (active pharmaceutical ingredient), such that the modular dosage forms exhibited pH-independent drug release. Tablet-like dosage forms of ciprofloxacin (CPR), used as model weak-base drug, were prepared in order to generate dosage forms exhibiting pH-independent drug release. The dosage forms were made by assembling two types of prefabricated modules onto 3D stacks. The modules were hydroxypropyl methylcellulose circular film wafers, loaded with either CPR or citric acid (CA). CA-wafers served the function of pH-modifier modules in the microenvironment of the dosage form during the dissolution process. In vitro drug release from dosage forms consisting of CA- and CPR-wafers stacked in alternate sequence was compared with the release from assemblies containing CPR-wafers only, under pH = 1.2 and pH = 6.8 conditions. In the absence of CA-wafers, CPR release was ~25-fold slower at pH = 6.8 compared to pH = 1.2. Inclusion of CA-wafers in the dosage form assembly accelerated and decelerated drug release at pH = 6.8 and pH = 1.2, respectively, which resulted in overlapping drug release profiles under the two pH conditions. The two drug release profiles met the criteria for sameness as assessed by the f1 (difference) and f2 (similarity) factors. Modeling of drug release kinetics pointed toward polymer erosion as the primary mechanism of drug release for the overlapping pH = 1.2 and pH = 6.8 profiles. In terms of their drug release properties, the multi-modular dosage form assemblies exhibited the attributes and behavior of single bodies, rather than the combined contributions from multiple individually-operating modules. The initial geometry of the dosage form, characterized by the surface area (SA), volume (V) and SA/V ratio accounted for drug release kinetics in the same fashion as for traditional tablet compacts.
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Affiliation(s)
- Mario A Cano-Vega
- Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN, USA; Bindley Bioscience Center, Purdue University, West Lafayette, IN, USA
| | - Meng Deng
- Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN, USA; Bindley Bioscience Center, Purdue University, West Lafayette, IN, USA; School of Materials Engineering, Purdue University, West Lafayette, IN, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Rodolfo Pinal
- Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN, USA.
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RÖDING M, FAGER C, OLSSON A, VON CORSWANT C, OLSSON E, LORÉN N. Three-dimensional reconstruction of porous polymer films from FIB-SEM nanotomography data using random forests. J Microsc 2021; 281:76-86. [PMID: 33439497 PMCID: PMC7754501 DOI: 10.1111/jmi.12950] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/22/2020] [Accepted: 07/23/2020] [Indexed: 11/29/2022]
Abstract
Combined focused ion beam and scanning electron microscope (FIB-SEM) tomography is a well-established technique for high resolution imaging and reconstruction of the microstructure of a wide range of materials. Segmentation of FIB-SEM data is complicated due to a number of factors; the most prominent is that for porous materials, the scanning electron microscope image slices contain information not only from the planar cross-section of the material but also from underlying, exposed subsurface pores. In this work, we develop a segmentation method for FIB-SEM data from ethyl cellulose porous films made from ethyl cellulose and hydroxypropyl cellulose (EC/HPC) polymer blends. These materials are used for coating pharmaceutical oral dosage forms (tablets or pellets) to control drug release. We study three samples of ethyl cellulose and hydroxypropyl cellulose with different volume fractions where the hydroxypropyl cellulose phase has been leached out, resulting in a porous material. The data are segmented using scale-space features and a random forest classifier. We demonstrate good agreement with manual segmentations. The method enables quantitative characterization and subsequent optimization of material structure for controlled release applications. Although the methodology is demonstrated on porous polymer films, it is applicable to other soft porous materials imaged by FIB-SEM. We make the data and software used publicly available to facilitate further development of FIB-SEM segmentation methods. LAY DESCRIPTION: For imaging of very fine structures in materials, the resolution limits of, e.g. X-ray computed tomography quickly become a bottleneck. Scanning electron microscopy (SEM) provides a way out, but it is essentially a two-dimensional imaging technique. One manner in which to extend it to three dimensions is to use a focused ion beam (FIB) combined with a scanning electron microscopy and acquire tomography data. In FIB-SEM tomography, ions are used to perform serial sectioning and the electron beam is used to image the cross section surface. This is a well-established method for a wide range of materials. However, image analysis of FIB-SEM data is complicated for a variety of reasons, in particular for porous media. In this work, we analyse FIB-SEM data from ethyl cellulose porous films made from ethyl cellulose and hydroxypropyl cellulose (EC/HPC) polymer blends. These films are used as coatings for controlled drug release. The aim is to perform image segmentation, i.e. to identify which parts of the image data constitute the pores and the solid, respectively. Manual segmentation, i.e. when a trained operator manually identifies areas constituting pores and solid, is too time-consuming to do in full for our very large data sets. However, by performing manual segmentation on a set of small, random regions of the data, we can train a machine learning algorithm to perform automatic segmentation on the entire data sets. The method yields good agreement with the manual segmentations and yields porosities of the entire data sets in very good agreement with expected values. The method facilitates understanding and quantitative characterization of the geometrical structure of the materials, and ultimately understanding of how to tailor the drug release.
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Affiliation(s)
- M. RÖDING
- RISE Research Institutes of Sweden, Biomaterials and HealthAgriculture and FoodGöteborgSweden
- Department of Mathematical SciencesChalmers University of Technology and University of GothenburgGöteborgSweden
| | - C. FAGER
- Department of PhysicsChalmers University of TechnologyGöteborgSweden
| | | | | | - E. OLSSON
- Department of PhysicsChalmers University of TechnologyGöteborgSweden
| | - N. LORÉN
- RISE Research Institutes of Sweden, Biomaterials and HealthAgriculture and FoodGöteborgSweden
- Department of PhysicsChalmers University of TechnologyGöteborgSweden
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Gehrcke M, de Bastos Brum T, da Rosa LS, Ilha BD, Soares FZM, Cruz L. Incorporation of nanocapsules into gellan gum films: A strategy to improve the stability and prolong the cutaneous release of silibinin. Mater Sci Eng C Mater Biol Appl 2020; 119:111624. [PMID: 33321666 DOI: 10.1016/j.msec.2020.111624] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/28/2020] [Accepted: 10/09/2020] [Indexed: 10/23/2022]
Abstract
This study aimed to develop gellan gum films containing silibinin-loaded nanocapsules as a novel approach for cutaneous administration of this flavonoid. The nanocapsule suspensions were prepared and presented mean size around 140 nm with homogenous distribution, negative zeta potential and silibinin encapsulation efficiency close to 100%. Then, these suspensions were converted into gellan gum films by solvent casting method. The films were transparent, flexible and maintained the gellan gum hydrophilicity. Nanocapsules provided the silibinin homogenous distribution in the films and prolonged its release, as well as improved the gellan gum occlusion potential. Besides, the nanosuspensions conversion into films improved the silibinin stability. Additionally, the nano-based films presented a swelling index 1.5 times higher than films containing non-nanoencapsulated silibinin. Microscopic analysis evidenced the homogeneous surface of the nano-based films, while films containing non-nanoencapsulated silibinin presented small cracks. The in vitro skin permeation profile confirmed the silibinin gradual release from the nano-based films and its greater retention in the dermis when the skin is damaged. Finally, the formulations presented no irritant effect in the HET-CAM assay. Therefore, the conversion of silibinin-loaded nanocapsule suspensions into films might be considered a promising platform for skin delivery of this flavonoid.
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Affiliation(s)
- Mailine Gehrcke
- Laboratório de Tecnologia Farmacêutica, Programa de Pós-graduação em Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Taíne de Bastos Brum
- Laboratório de Tecnologia Farmacêutica, Programa de Pós-graduação em Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Lucas Saldanha da Rosa
- Departamento de Odontologia Restauradora, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Bruna Dias Ilha
- Departamento de Odontologia Restauradora, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Fabio Zovico Maxnuck Soares
- Departamento de Odontologia Restauradora, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Letícia Cruz
- Laboratório de Tecnologia Farmacêutica, Programa de Pós-graduação em Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
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Arnaudguilhem C, Larroque M, Sgarbura O, Michau D, Quenet F, Carrère S, Bouyssière B, Mounicou S. Toward a comprehensive study for multielemental quantitative LA-ICP MS bioimaging in soft tissues. Talanta 2020; 222:121537. [PMID: 33167245 DOI: 10.1016/j.talanta.2020.121537] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 08/07/2020] [Accepted: 08/10/2020] [Indexed: 10/23/2022]
Abstract
Quantitative localization of metals in biological tissue sections is critical to obtain insight into metal toxicity mechanisms or their beneficial characteristics. This study presents the development of a quantitative LA-ICP MS bioimaging methodology based on the polymer film strategy and internal standardization. To maximize the number of elements mapped, an aqueous soluble polymer (dextran) was selected. Among the elements studied, the great majority (eight out eleven), i.e., Co, Ni, Cu, Zn, Se, Mo, Cd and Pt, exhibited linear regression after LA-ICP MS analysis of metal-spiked polymer standards. Methodology performances were carefully assessed as a function of the three internal standards (In, Rh and Ir) considered, the analytical operational conditions (ICP power, addition of O2 to ICP, and laser fluency) and the thickness of the biological tissue section. The results indicated that three groups (Co, Mo; Ni, Cu, Pt; and Zn, Se, Cd) of elements could be distinguished from their analytical response as a function of analytical conditions and the internal standard. These different element behaviors appeared to be mainly First Ionization Potential dependent (FIP). For elements with lower FIP (Co, Ni, Cu, Mo and Pt), differential responses due to carbon load in the ICP MS plasma could be efficiently corrected as a function of analytical conditions. Matrix effects were more pronounced for higher FIP elements (i.e., Zn, Cd and Se), and analysis of <10-μm thin sections without the addition of O2 to ICP MS plasma is recommended. LODs are in the range of 0.1-0.5 μg g-1 for Co, Mo, Cu, Ni, Pt and Cd as well as 0.9 and 1 μg g-1 for Zn and Se, respectively. The methodology was validated by means of a homemade metal-spiked kidney homogenate analyzed by LA-ICP MS imaging, and Co, Ni, Cu, Mo, and Pt provided the closest concentrations (5-29% bias) to the target values determined by ICP MS after mineralization. The methodology was applied to two types of clinical human samples undergoing different sample preparation protocols that did not affect internal standard homogeneity in the polymer film. This methodology is the first reported for the quantitative bioimaging of eight elements simultaneously.
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Affiliation(s)
- Carine Arnaudguilhem
- Universite de Pau et des Pays de L'Adour, E2S UPPA, CNRS, Institut des Sciences Analytiques et de Physico-Chimie Pour L'Environnement et Les Materiaux (IPREM), UMR5254, Hélioparc, 64053, Pau, France
| | - Marion Larroque
- Universite de Pau et des Pays de L'Adour, E2S UPPA, CNRS, Institut des Sciences Analytiques et de Physico-Chimie Pour L'Environnement et Les Materiaux (IPREM), UMR5254, Hélioparc, 64053, Pau, France; Institut Du Cancer de Montpellier, Unité de Recherche Translationnelle, Montpellier, France
| | - Olivia Sgarbura
- Institut Du Cancer de Montpellier, Département Chirurgie, Montpellier, France
| | - Dominique Michau
- CNRS, Université Bordeaux, ICMCB, UMR 5026, 87 Avenue Du Dr A. Schweitzer, 33608, Pessac, France
| | - François Quenet
- Institut Du Cancer de Montpellier, Département Chirurgie, Montpellier, France
| | - Sébastien Carrère
- Institut Du Cancer de Montpellier, Département Chirurgie, Montpellier, France
| | - Brice Bouyssière
- Universite de Pau et des Pays de L'Adour, E2S UPPA, CNRS, Institut des Sciences Analytiques et de Physico-Chimie Pour L'Environnement et Les Materiaux (IPREM), UMR5254, Hélioparc, 64053, Pau, France
| | - Sandra Mounicou
- Universite de Pau et des Pays de L'Adour, E2S UPPA, CNRS, Institut des Sciences Analytiques et de Physico-Chimie Pour L'Environnement et Les Materiaux (IPREM), UMR5254, Hélioparc, 64053, Pau, France.
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9
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Hood J, Van Gordon K, Thomson P, Coleman BR, Burns F, Moffitt MG. Structural hierarchy in blends of amphiphilic block copolymers self-assembled at the air-water interface. J Colloid Interface Sci 2019; 556:392-400. [PMID: 31472313 DOI: 10.1016/j.jcis.2019.08.080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/21/2019] [Accepted: 08/22/2019] [Indexed: 11/26/2022]
Abstract
We present a concurrent self-assembly strategy for patterning hierarchical polymeric surface features by depositing variable-composition blends of polystyrene-block-poly(ethylene oxide) (PS-b-PEO) and polybutadiene-block-poly(ethylene oxide) (PB-b-PEO) block copolymers at the air-water interface. Hierarchical strand networks of hydrophobic PS/PB blocks anchored via PEO blocks to the water surface, with an internal phase-separation structure consisting of periodic domains of PS blocks surrounded and connected by a matrix of PB blocks, are generated by the interplay of interfacial amphiphilic block copolymer aggregation and polymer/polymer phase separation. In contrast to the cylinder-in-strand structures previously formed by our group in which interfacial microphase separation between PS and PB blocks was constrained by chemical connectivity between the blocks, in the current system phase separation between PS and PB is not constrained by chemical connectivity and yet is confined laterally within surface features at the air-water interface. Investigations of multi-component polymer systems with different connectivities constraining repulsive and attractive interactions provides routes to new hierarchical surface patterns for a variety of applications, including photolithography masks, display technology, surface-guided cell growth and tissue engineering.
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Affiliation(s)
- Janet Hood
- Department of Chemistry, University of Victoria, PO Box 1700 Stn CSC, Victoria, BC V8W 2Y2, Canada
| | - Kyle Van Gordon
- Department of Chemistry, University of Victoria, PO Box 1700 Stn CSC, Victoria, BC V8W 2Y2, Canada
| | - Patricia Thomson
- Department of Chemistry, University of Victoria, PO Box 1700 Stn CSC, Victoria, BC V8W 2Y2, Canada
| | - Brian R Coleman
- Department of Chemistry, University of Victoria, PO Box 1700 Stn CSC, Victoria, BC V8W 2Y2, Canada
| | - Fraser Burns
- Department of Chemistry, University of Victoria, PO Box 1700 Stn CSC, Victoria, BC V8W 2Y2, Canada
| | - Matthew G Moffitt
- Department of Chemistry, University of Victoria, PO Box 1700 Stn CSC, Victoria, BC V8W 2Y2, Canada
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Druzhko AB, Pirutin SK. Investigation of spectral and kinetic properties of polymer films based on some analogs of bacteriorhodopsin. Eur Biophys J 2019; 48:749-56. [PMID: 31642958 DOI: 10.1007/s00249-019-01401-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 09/26/2019] [Accepted: 10/03/2019] [Indexed: 10/25/2022]
Abstract
We investigated the characteristics of modified forms of bacteriorhodopsin in which the native retinal chromophore is replaced by a chemical analog ("bacteriorhodopsin analogs"), embedded in a polymer film. We found they displayed differential absorption spectra and kinetic curves for the most long-lived intermediates of the BR photocycle. We also studied the influence of chemical reagents on the functioning of bacteriorhodopsin analogs in polymeric films. We found that the immobilization of BR analogs in polymer leads, as in the case of native BR, to a slowing down of their photocycles. Kinetic analysis showed that M-like state intermediates of all the BR analogs have a longer dark relaxation time than native BR. The retention and retardation of the photocycle in these films suggest that films based on BR analogs can be used as photochromic materials. Moreover, 4-keto BR seems to be more promising for this application as compared not only with native BR, but also with other analogs of BR studied in this work.
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Forssell M, Ong XC, Khilwani R, Burak Ozdoganlar O, Fedder GK. Insulation of thin-film parylene-C/platinum probes in saline solution through encapsulation in multilayer ALD ceramic films. Biomed Microdevices 2018; 20:61. [PMID: 30051149 DOI: 10.1007/s10544-018-0307-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The long-term electrical leakage performance of parylene-C/platinum/parylene-C (Px/Pt/Px) interconnect in saline is evaluated using electrochemical impedance spectroscopy (EIS). Three kinds of additional ceramic encapsulation layers between the metal and Px are characterized: 50 nm-thick alumina (Al2O3), 50 nm-thick titania (TiO2), and 80 nm-thick Al2O3-TiO2 nanolaminate (NL). The Al2O3 and TiO2 encapsulation layers worsen the overall insulation properties. The NL encapsulation layer improves the insulation when combined with a TiO2 outer layer to promote adhesion to the Px. Experiments are performed with various insulation promotion treatments: A-174 silane (A174) treatment before Px deposition (to promote adhesion); SF6 plasma treatment (F) after Px deposition (to increase hydrophobicity); and ion-milling descum (IM) after Px deposition (to prevent parylene oxidation). A174 and F treatments do not have a significant impact, while IM leads to worse insulation performance. A circuit model elucidates the insulation characteristics of Px-ceramic-Pt-ceramic-Px interconnect. These studies provide a foundation for processing ultra-compliant neural probes with long-term chronic utility.
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Affiliation(s)
- Mats Forssell
- Department of Electrical and Computer Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA.
| | - Xiao Chuan Ong
- Department of Electrical and Computer Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA
| | - Rakesh Khilwani
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - O Burak Ozdoganlar
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Gary K Fedder
- Department of Electrical and Computer Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA.,The Robotics Institute, Carnegie Mellon University, Pittsburgh, PA, USA
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Raftari M, Zhang ZJ, Carter SR, Leggett GJ, Geoghegan M. Salt Dependence of the Tribological Properties of a Surface-Grafted Weak Polycation in Aqueous Solution. Tribol Lett 2017; 66:11. [PMID: 31983863 PMCID: PMC6951817 DOI: 10.1007/s11249-017-0963-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/23/2017] [Indexed: 06/10/2023]
Abstract
The nanoscopic adhesive and frictional behaviour of end-grafted poly[2-(dimethyl amino)ethyl methacrylate] (PDMAEMA) films (brushes) in contact with gold- or PDMAEMA-coated atomic force microscope tips in potassium halide solutions with different concentrations up to 300 mM is a strong function of salt concentration. The conformation of the polymers in the brush layer is sensitive to salt concentration, which leads to large changes in adhesive forces and the contact mechanics at the tip-sample contact, with swollen brushes (which occur at low salt concentrations) yielding large areas of contact and friction-load plots that fit JKR behaviour, while collapsed brushes (which occur at high salt concentrations) yield sliding dominated by ploughing, with conformations in between fitting DMT mechanics. The relative effect of the different anions follows the Hofmeister series, with I- collapsing the brushes more than Br- and Cl- for the same salt concentration.
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Affiliation(s)
- Maryam Raftari
- Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH UK
| | - Zhenyu J. Zhang
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF UK
- Present Address: School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT UK
| | - Steven R. Carter
- Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH UK
| | - Graham J. Leggett
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF UK
| | - Mark Geoghegan
- Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH UK
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