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  • 151.
    Eriksson, Emil
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Integration of microfluidic sample handlingwith ultra-sensitive magnetic bioassay usinghigh-Tc Superconducting Quantum InterferenceDevice readout2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Immunoassays are a very sensitive molecular diagnostics technique

    that uses biochemical reactions to measure concentration of

    biomolecules in a solution. ELISA is one of the most commonly used

    type, based on fluorescence, in routine medicaldiagnostics. It is

    time consuming and requires relatively large sample volumes.

    Immunoassays based on magnetic detection are being developed. They

    are faster, able to be made into point of care devices with

    biological samples often lacking magnetic background. This project

    focuses on developing an magnetic bioassay based on a high-Tc

    SQUID with magnetic nanoparticles as tags. The expected

    performance maybe two orders of magnitude better than ELISA

    techniques, while not requiring several washing steps and being

    able to perform in real time. Method of detection is based on

    utilizing a padlock DNA probe-based recognition mechanism to

    enhance the size ofviral flu RNA, binding the nanoparticles to the

    padlocks and measuring the change in amplitude of the Brownian

    relaxation peak of the unbound nanoparticles.

    This thesis has been focused on developing a microfluidic sample

    holder. Mircofluidics offer an advanced way to handle liquid

    samples, with preparation, dilution, mixing and incubation on the

    same chip, so called lab on a chip. During this thesis,

    microfluidic channels made of PDMS were created. PDMS is a

    suitable material because it is relatively cheap, easy to

    manufacture and particles or padlocks do not bind to it.

    Measurements of the real and imaginary parts of the AC

    susceptibility as a function of concentration of both non

    functionalized and functionalized magnetic nanoparticles

    were performed in the microchannel with a volume of about 3 micro

    liter. Extrapolating the results showed an equivalent iron content

    sensitivity of 2*10^5 particles at 10 Hz. This result is about one

    order of magnitude better than obtained in bulk samples of larger

    volume.

  • 152. Fadeel, B.
    et al.
    Kasemo, B.
    Malmsten, Martin
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Nanomedicine: reshaping clinical practice2010Inngår i: Journal of Internal Medicine, ISSN 0954-6820, E-ISSN 1365-2796, Vol. 267, nr 1, s. 2-8Artikkel i tidsskrift (Fagfellevurdert)
  • 153. Fadeel, Bengt
    et al.
    Garcia-Bennett, Alfonso E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Better safe than sorry: understanding the toxicological properties of inorganic nanoparticles manufactured for biomedical applications2010Inngår i: Advanced Drug Delivery Reviews, ISSN 0169-409X, E-ISSN 1872-8294, Vol. 62, nr 3, s. 362-374Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The development of nanoparticles for biomedical applications including medical imaging and drug delivery is currently undergoing a dramatic expansion. However, as the range of nanoparticle types and applications increases, it is also clear that the potential toxicities of these novel materials and the properties driving such toxic responses must also be understood. Indeed, a detailed assessment of the factors that influence the biocompatibility and/or toxicity of nanoparticles is crucial for the safe and sustainable development of the emerging nanotechnologies. This review summarizes some of the recent developments in the field of nanomedicine with particular emphasis on inorganic nanoparticles for drug delivery. The synthesis routes, physico-chemical characteristics, and cytotoxic properties of inorganic nanoparticles are thus explored and lessons learned from the toxicological investigation of three common types of engineered nanomaterials of titania, gold, and mesoporous silica are discussed. Emphasis is placed on the recognition versus non-recognition of engineered nanomaterials by the immune system, the primary surveillance system against microorganisms and particles, which, in turn, is intimately linked to the issue of targeted drug delivery using such nanomaterials as carrier systems.

  • 154. Fernandez-Cruz, M
    et al.
    Hernández-Moreno, D
    Catalán, J
    Janer, G
    Cross, R
    Stockmann-Juvala, H
    Matzke, M
    Izquierdo, J
    Navas, J
    Park, M
    Ferraz, Natalia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Svendsen, C
    A web-tool based approach to evaluate the quality of an (eco)/toxicity study performed with nanomaterials.2017Konferansepaper (Fagfellevurdert)
  • 155. Fernandez-Cruz, Maria Luisa
    et al.
    Hernandez-Moreno, David
    Catalan, Julia
    Cross, Richard
    Stockmann-Juvala, Helene
    Cabellos, Joan
    Lopes, Viviana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Matzke, Marianne
    Ferraz, Natalia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Izquierdo, Juan Jose
    Navas, José Maria
    Park, Margriet VDZ
    Svendsen, Claus
    Janer, Gemma
    Quality evaluation of human and environmental toxicity studies performed with nanomaterials – the GUIDEnano approach2018Inngår i: Environmental Science: Nano, Vol. 5, nr 2, s. 381-397Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The European Union FP-7 project GUIDEnano developed a web-based guidance tool, which guides users to assess human and environmental risks of nanomaterial-enabled products throughout their life cycle. One of the aims in the GUIDEnano hazard assessment strategy is to derive safety limit values based on existing human toxicity and ecotoxicological studies. Clear criteria needed to be established to select studies that could be used for such purpose. In the present paper, we present an approach for a systematical and quantitative evaluation of the quality of environmental and human toxicity studies performed with nanomaterials. The approach builds upon previous initiatives and includes refinements to facilitate its application by users with limited toxicological expertise. It covers in vivo and in vitro human toxicity studies as well as ecotoxicological studies addressing the toxicity to all environmental compartments. A scoring system related to test design and reporting considerations was developed following the principles of the Klimisch score (K score). In addition, the approach includes a scoring system based on the physicochemical properties that have been characterized and reported for the nanomaterial, including properties characterized in the exposure medium (S score). These two scores (K and S) are combined to obtain an overall quality score (Q score) that can be used to select studies, to weight different studies, and/or to introduce uncertainty factors in the risk assessment process. During its development, the approach has been tested and refined with 137 peer-reviewed articles. The final quality assessment approach and the results of its evaluation are presented here.

  • 156.
    Fernholm, Ann
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Ingvald, Erika
    Sjöstedt, Elisabeth
    Där Guld Glimmar Blått: forskare om den lilla nanorevolutionen2007Bok (Fagfellevurdert)
  • 157.
    Fernholm, Ann
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Ingvald, Erika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Sjöstedt, Elisabeth
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Where Gold Glints Blue: Scientists on the Nanorevolution2008Bok (Annet (populærvitenskap, debatt, mm))
  • 158.
    Ferraz, Natalia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Nanocellulose for biomedical applications2018Inngår i: Uppsala Biomaterials and Bioengineering Meeting September 4th, 2018., 2018Konferansepaper (Fagfellevurdert)
  • 159.
    Ferraz, Natalia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    The Guide Nano Project2014Inngår i: NFM conference, Prague 16-18th June 2014., 2014Konferansepaper (Annet vitenskapelig)
  • 160.
    Ferraz, Natalia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Carlsson, Daniel O.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Hong, Jaan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Klinisk immunologi.
    Larsson, Rolf
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Klinisk immunologi.
    Fellström, Bengt
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper, Njurmedicin.
    Nyholm, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Haemocompatibility and ion exchange capability of nanocellulose polypyrrole membranes intended for blood purification2012Inngår i: Journal of the Royal Society Interface, ISSN 1742-5689, E-ISSN 1742-5662, Vol. 9, nr 73, s. 1943-1955Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Composites of nanocellulose and the conductive polymer polypyrrole (PPy) are presented as candidates for a new generation of haemodialysis membranes. The composites may combine active ion exchange with passive ultrafiltration, and the large surface area (about 80 m2 g−1) could potentially provide compact dialysers. Herein, the haemocompatibility of the novel membranes and the feasibility of effectively removing small uraemic toxins by potential-controlled ion exchange were studied. The thrombogenic properties of the composites were improved by applying a stable heparin coating. In terms of platelet adhesion and thrombin generation, the composites were comparable with haemocompatible polymer polysulphone, and regarding complement activation, the composites were more biocompatible than commercially available membranes. It was possible to extract phosphate and oxalate ions from solutions with physiological pH and the same tonicity as that of the blood. The exchange capacity of the materials was found to be 600 ± 26 and 706 ± 31 μmol g−1 in a 0.1 M solution (pH 7.4) and in an isotonic solution of phosphate, respectively. The corresponding values with oxalate were 523 ± 5 in a 0.1 M solution (pH 7.4) and 610 ± 1 μmol g−1 in an isotonic solution. The heparinized PPy–cellulose composite is consequently a promising haemodialysis material, with respect to both potential-controlled extraction of small uraemic toxins and haemocompatibility.

  • 161.
    Ferraz, Natalia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Carlsson, Daniel O
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Hong, Jaan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Klinisk immunologi.
    Larsson, Rolf
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Klinisk immunologi.
    Fellström, Bengt
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper.
    Nyholm, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Hemocompatibility of Nanocellulose Polypyrrole Membranes Intended for Hemodialysis2012Inngår i: 9th World Biomaterials Congress, June 1-5, 2012, Chengdu, China, 2012Konferansepaper (Fagfellevurdert)
  • 162.
    Ferraz, Natalia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Hoess, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Thormann, Annika
    Heilmann, Andreas
    Shen, Jinhui
    Tang, Liping
    Karlsson Ott, Marjam
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Role of Alumina Nanoporosity in Acute Cell Response2011Inngår i: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 11, nr 8, s. 6698-6704Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work studied the effect of nanoporous alumina in acute cellular response in an in vivo model. Nanoporous alumina membranes, with pore size diameters of 20 and 200 nm, were fabricated by anodic oxidation of aluminium. The membranes were thereafter characterized in terms of pore size distribution and chemical composition. To evaluate acute inflammatory response, the membranes were implanted in the peritoneal cavity of mice. Cell recruitment to the implant site was determined by fluorescence activated cell sorting (FACS) analysis. Cell adhesion to material surfaces was studied in terms of cell number, type, and morphology using scanning electron microscopy (SEM) and immunocytochemical staining followed by fluorescence microscopy. The fabricated nanoporous alumina membranes were found to have narrow pore size distribution. The in vivo study showed that 200 nm alumina membranes induced stronger inflammatory response than 20 nm membranes. This was reflected by the number of implant-associated phagocytes and the number of cells recruited to the implantation site. Since both pore-size membranes possess similar chemical composition, we believe that the observed difference in cell recruitment and adhesion is an effect of the material nanotopography. Our results suggest that nanotopography can be used to subtly control the recruitment and adherence of phagocytic cells during the acute inflammatory response to alumina membranes.

  • 163.
    Ferraz, Natalia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Leschinskaya, Anastasia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Toomadj, Farshad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Fellström, Bengt
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Membrane characterization and solute diffusion in porous composite nanocellulose membranes for hemodialysis2013Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 20, nr 6, s. 2959-2970Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The membrane and solute diffusion properties of Cladophora cellulose and polypyrrole (PPy) functionalized Cladophora cellulose were analyzed to investigate the feasibility of using electroactive membranes in hemodialysis. The membranes were characterized with scanning electron microscopy, zeta-potentiometry, He-pycnometry, N-2 gas adsorption, and Hg porosimetry. The diffusion properties across the studied membranes for three model uremic toxins, i.e. creatinine, vitamin B12 and bovine serum albumin, were also analyzed. The characterization work revealed that the studied membranes present an open structure of weakly negatively charged nanofibers with an average pore size of 21 and 53 nm for pristine cellulose and PPy-Cladophora cellulose, respectively. The results showed that the diffusion of uremic toxins across the PPy-Cladophora cellulose membrane was faster than through pure cellulose membrane, which was related to the higher porosity and larger average pore size of the former. Since it was found that the average pore size of the membranes was larger than the hydrodynamic radius of the studied model solutes, it was concluded that these types of membranes are favorable to expand the Mw spectrum of uremic toxins to also include conditions associated with accumulation of large pathologic proteins during hemodialysis. The large average pore size of the composite membrane could also be exploited to ensure high-fluxes of solutes through the membrane while simultaneously extracting ions by an externally applied electric current.

  • 164.
    Ferraz, Natalia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Lopes, Viviana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Navarro, J.
    Breitholtz, Magnus
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Lindström, Tom
    Turning forestry biomass into sustainable nanocellulose based materials2016Inngår i: Insights and Strategies Towards a Bio-Based Economy 22-25 Nov 2016, Montevideo, Uruguay., 2016Konferansepaper (Fagfellevurdert)
  • 165.
    Ferraz, Natalia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Is there a future for electrochemically assisted hemodialysis?: Focus on the application of polypyrrole-nanocellulose composites2014Inngår i: Nanomedicine, ISSN 1743-5889, E-ISSN 1748-6963, Vol. 9, nr 7, s. 1095-1110Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    This work summarizes the various aspects of using electrochemically assisted solute removal techniques in hemodialysis with a focus on blood electrodialysis and electrochemically controlled uremic retention solute removal using polypyrrole. In particular, the feasibility of using highly porous conductive polypyrrole-Cladophora cellulose membranes for hemodialysis are overviewed as a part of our dedicated research efforts during the past 4 years. The potential benefits and the current limitations associated with using the electrochemically controlled uremic retention solute removal techniques are discussed in detail.

  • 166.
    Ferraz, Natalia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Biocompatibility of Novel Nano-engineering Cellulose-polypyrrole Composite.2011Inngår i: MRS 2011 Spring meeting San Francisco: Hybrid Biological Materials II, 2011Konferansepaper (Fagfellevurdert)
  • 167.
    Ferraz, Natalia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Fellström, Bengt
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper.
    Pradhan, Sulena
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Nyholm, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    In vitro and in vivo toxicity of rinsed and aged nanocellulose-polypyrrole composites2012Inngår i: Journal of Biomedical Materials Research. Part A, ISSN 1549-3296, E-ISSN 1552-4965, Vol. 100A, nr 8, s. 2128-2138Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Novel composites of nanocellulose and the conducting polymer polypyrrole (PPy) are herein suggested as potential candidates for active ion-extraction membranes in electrochemically controlled hemodialysis. This work has defined processing parameters to obtain a biocompatible nanocellulose-PPy composite and for the first time, the effect of the composite ageing on cell viability has been studied.

    The influence of rinsing and extraction process steps, as well as ageing under different conditions (i.e. in air, at –20 ˚C and in argon), on the electroactivity and cytotoxicity of a PPy-nanocellulose composite has been investigated. The biocompatibility evaluation was based on indirect toxicity assays with fibroblasts and monocyte cell lines and an acute toxicity test in mice, while the electroactivity was evaluated by cyclic voltammetry experiments.

    The as-prepared composite did not induce any cytotoxic response in vitro or in vivo. Extensive rinsing and 48 hour incubation in biological buffer previous to the preparation of the culture medium extracts were, however, necessary to obtain a non-cytotoxic composite. The as-prepared composite was also found to exhibit acceptable electrochemical performance, which was retained upon 4 weeks storage in argon atmosphere.  It was shown that ageing of the composite had a negative effect on biocompatibility, regardless of the storage condition. Thus, to allow for long time storage of electroactive nanocellulose-PPy hemodialysis membranes, the degradation of PPy upon storage must be controlled. The present results show that the biocompatibility of PPy composites depends on the rinsing and pre-treatment of the composite material as well as the aging of the material.

  • 168.
    Fichtner, Frauke
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Mahlin, Denny
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Welch, Ken
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Gaisford, Simon
    Alderborn, Göran
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Effect of surface energy on powder compactibility2008Inngår i: Pharmaceutical research, ISSN 0724-8741, E-ISSN 1573-904X, Vol. 25, nr 12, s. 2750-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PURPOSE: The influence of surface energy on the compactibility of lactose particles has been investigated. MATERIALS AND METHODS: Three powders were prepared by spray drying lactose solutions without or with low proportions of the surfactant polysorbate 80. Various powder and tablet characterisation procedures were applied. The surface energy of the powders was characterized by Inverse Gas Chromatography and the compressibility of the powders was described by the relationship between tablet porosity and compression pressure. The compactibility of the powders was analyzed by studying the evolution of tablet tensile strength with increasing compaction pressure and porosity. RESULTS: All powders were amorphous and similar in particle size, shape, and surface area. The compressibility of the powders and the microstructure of the formed tablets were equal. However, the compactibility and dispersive surface energy was dependent of the composition of the powders. CONCLUSION: The decrease in tablet strength correlated to the decrease in powder surface energy at constant tablet porosities. This supports the idea that tablet strength is controlled by formation of intermolecular forces over the areas of contact between the particles and that the strength of these bonding forces is controlled by surface energy which, in turn, can be altered by the presence of surfactants.

  • 169.
    Forsgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Assessment of Batch-to-Batch-Variability in Representative Nanoparticle Syntheses with Characterisation of OECD Proposed Parameters.2013Konferansepaper (Fagfellevurdert)
  • 170.
    Forsgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Batch-to-batch reproducibility: a challenge for safety assessment and regulation2013Konferansepaper (Fagfellevurdert)
  • 171.
    Forsgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Functional Ceramics in Biomedical Applications: On the Use of Ceramics for Controlled Drug Release and Targeted Cell Stimulation2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Ceramics are distinguished from metals and polymers by their inorganic nature and lack of metallic properties. They can be highly crystalline to amorphous, and their physical and chemical properties can vary widely. Ceramics can, for instance, be made to resemble the mineral phase in bone and are therefore an excellent substitute for damaged hard tissue. They can also be made porous, surface active, chemically inert, mechanically strong, optically transparent or biologically resorbable, and all these properties are of interest in the development of new materials intended for a wide variety of applications. In this thesis, the focus was on the development of different ceramics for use in the controlled release of drugs and ions. These concepts were developed to obtain improved therapeutic effects from orally administered opioid drugs, and to reduce the number of implant-related infections as well as to improve the stabilization of prosthetic implants in bone.

    Geopolymers were used to produce mechanically strong and chemically inert formulations intended for oral administration of opioids. The carriers were developed to allow controlled release of the drugs over several hours, in order to improve the therapeutic effect of the substances in patients with severe chronic pain. The requirement for a stable carrier is a key feature for these drugs, as the rapid release of the entire dose, due to mechanical or chemical damage to the carrier, could have lethal effects on the patient because of the narrow therapeutic window of opioids. It was found that it was possible to profoundly retard drug release and to achieve almost linear release profiles from mesoporous geopolymers when the aluminum/silicon ratio of the precursor particles and the curing temperature were tuned.

    Ceramic implant coatings were produced via a biomimetic mineralization process and used as carriers for various drugs or as an ion reservoir for local release at the site of the implant. The formation and characteristics of these coatings were examined before they were evaluated as potential drug carriers. It was demonstrated that these coatings were able to carry antibiotics, bisphosphonates and bone morphogenetic proteins to obtain a sustained local effect, as they were slowly released from the coatings.

     

    Delarbeid
    1. A ceramic drug delivery vehicle for oral administration of highly potent opioids
    Åpne denne publikasjonen i ny fane eller vindu >>A ceramic drug delivery vehicle for oral administration of highly potent opioids
    Vise andre…
    2010 (engelsk)Inngår i: Journal of Pharmaceutical Sciences, ISSN 0022-3549, E-ISSN 1520-6017, Vol. 99, nr 1, s. 219-226Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Pellets composed of the ceramic material Halloysite and microcrystalline cellulose were synthesized with the aim of producing a drug delivery vehicle for sustained release of the opioid Fentanyl with low risk for dose dumping at oral intake of the highly potent drug. Drug release profiles of intact and crushed pellets, to simulate swallowing without or with chewing, in pH 6.8, pH 1, and in 48% ethanol were recorded in order to replicate the conditions in the small intestines, in the stomach, as well as cointake of the drug with alcohol. The drug release was analyzed by employing the Weibull equation, which showed that the release profiles were either governed by fickian diffusion (intact pellets in pH 6.8 and in ethanol) or by diffusion in a fractal or disordered pore network (intact pellets in pH 1 and crushed pellets in all solutions). A sustained release for approximately 3-4 h was obtained in all studied solutions from intact pellets, whereas crushed pellets released the drug content during approximately 2-3 h. The finding that a sustained release profile could be obtained both in alcohol and after crushing of the pellets, shows that the ceramic carrier under investigation, at least to some extent, hampers dose dumping, and may thus be a promising material in future developments of new opioid containing oral dosage forms.

    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot nanoteknologi och funktionella material
    Identifikatorer
    urn:nbn:se:uu:diva-111786 (URN)10.1002/jps.21814 (DOI)000273151500016 ()19492338 (PubMedID)
    Tilgjengelig fra: 2009-12-21 Laget: 2009-12-21 Sist oppdatert: 2018-11-05bibliografisk kontrollert
    2. Mechanically strong geopolymers offer new possibilities in treatment of chronic pain
    Åpne denne publikasjonen i ny fane eller vindu >>Mechanically strong geopolymers offer new possibilities in treatment of chronic pain
    Vise andre…
    2010 (engelsk)Inngår i: Journal of Controlled Release, ISSN 0168-3659, E-ISSN 1873-4995, Vol. 146, nr 3, s. 370-377Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    We propose that a clay derived class of materials, known as geopolymers, may solve the problem of finding materials for controlled release with the right combination of properties necessary for a safe and sustained oral delivery of highly potent opioids. We show that the opioid Fentanyl, and its structurally similar sedative Zolpidem, can be embedded into metakaolin based geopolymer pellets to provide prolonged release dosage forms with mechanical strengths of the same order of magnitude as that of human teeth. The results presented in the current work may open up new opportunities for future development of drug delivery for high potency drugs employing high-strength and variable-pore-structure geopolymers and materials alike.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-131243 (URN)10.1016/j.jconrel.2010.05.029 (DOI)000282398100014 ()20685295 (PubMedID)
    Tilgjengelig fra: 2010-09-28 Laget: 2010-09-28 Sist oppdatert: 2018-11-05bibliografisk kontrollert
    3. Adjustable nanostructure of synthetic geopolymers enables tunable and sustained release of oxycodone
    Åpne denne publikasjonen i ny fane eller vindu >>Adjustable nanostructure of synthetic geopolymers enables tunable and sustained release of oxycodone
    (engelsk)Artikkel i tidsskrift (Fagfellevurdert) Submitted
    Identifikatorer
    urn:nbn:se:uu:diva-132372 (URN)
    Tilgjengelig fra: 2010-10-19 Laget: 2010-10-19 Sist oppdatert: 2011-01-13bibliografisk kontrollert
    4. Formation and adhesion of biomimetic hydroxyapatite deposited on titanium substrates
    Åpne denne publikasjonen i ny fane eller vindu >>Formation and adhesion of biomimetic hydroxyapatite deposited on titanium substrates
    2007 (engelsk)Inngår i: Acta Biomaterialia, ISSN 1742-7061, Vol. 3, nr 6, s. 980-984Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This study has been carried out to investigate the bioactivity of rutile and to deposit hydroxyapatite (HA) on heat-treated titanium through a biomimetic method. Biomimetic deposition of HA has gained large interest because of its low deposition temperature and good step coverage; however, it demands a substrate with bioactive properties. Commercially pure titanium is not bioactive but it can acquire bioactive properties through various surface treatments. In the present study, titanium plates were heat-treated at 800 °C to achieve rutile TiO2 surfaces. These samples were immersed in a phosphate-buffered saline solution for seven days in order to deposit a HA layer on the surface. The rutile TiO2 surfaces were found to be highly bioactive: after seven days of immersion, a layer of HA several micrometers thick covered the plates. The HA surfaces were confirmed by electron microscopy and X-ray diffraction. A scratch test was used to assess the adhesion of the HA coatings. This is a standard method to provide a measure of the coating-to-substrate adhesion and was found to be a useful method to test the thin HA coatings deposited on the bioactive surfaces. The critical pressure of the layer was estimated to be 2.4 ± 0.1 GPa.

    Emneord
    Hydroxyapatite, Bioactivity, Biomimetic deposition, Rutile, Adhesion
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-13067 (URN)10.1016/j.actbio.2007.03.006 (DOI)000250394000017 ()17512265 (PubMedID)
    Tilgjengelig fra: 2008-06-09 Laget: 2008-06-09 Sist oppdatert: 2018-02-08bibliografisk kontrollert
    5. Structural change of biomimetic hydroxyapatite coatings due to heat treatment
    Åpne denne publikasjonen i ny fane eller vindu >>Structural change of biomimetic hydroxyapatite coatings due to heat treatment
    2007 (engelsk)Inngår i: Journal of Applied Biomaterials & Biomechanics, ISSN 1722-6899, Vol. 5, nr 1, s. 23-27Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Biomimetic deposition of hydroxyapatite (HA) coatings on implants could be done for two reasons, one is to study their possible bioactivity, and one is to generate bioactive coatings on implants before implantation surgery to improve the osseointegration. Heat treatment of coated implants can be performed for several reasons, for example, to ensure coating sterility and to increase the adhesion. This paper describes the morphology and crystalline structure changes occurring due to the heat treatment of biomimetic HA coatings on rutile TiO2. Rutile TiO2 surfaces were produced on titanium (Ti) plates by heating at 800 C. Afterwards, these samples were immersed in a phosphate buffer saline solution for 7 days at 37 C in order to deposit HA coatings on their surfaces. These HA coatings were then either untreated or heat treated at 600 or 800 C for 1 hr. The coatings microstructural changes were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Cross-sectional TEM samples were produced using a sample preparation method based on focused ion beam microscopy (FIB). Rutile was found to be bioactive due to HA formation on the surface. The 600 C heat treatment of the HA coating changed its morphology, increased its grain size and also increased the porosity. At 800 C the coating was completely transformed to beta-TCP according to XRD. Sample preparation using FIB and TEM analysis proved to be a useful method for high-resolution analysis of biomimetic coatings in cross-section.

    Emneord
    microstructure, titanium, biomimetic coating, stability
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot nanoteknologi och funktionella material
    Identifikatorer
    urn:nbn:se:uu:diva-16172 (URN)000255726200003 ()
    Tilgjengelig fra: 2008-06-09 Laget: 2009-02-26 Sist oppdatert: 2018-02-08bibliografisk kontrollert
    6. Assessing Surface Area Evolution during Biomimetic Growth of Hydroxyapatite Coatings
    Åpne denne publikasjonen i ny fane eller vindu >>Assessing Surface Area Evolution during Biomimetic Growth of Hydroxyapatite Coatings
    2009 (engelsk)Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 25, nr 3, s. 1292-1295Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The surface area of biomimetically deposited hydroxyapatite (HA) coatings on metallic implants is important for the biological performance of the implant. Thus, a nondestructive method of assessing this quantity directly on the solid substrate would be highly valuable. The objective of this study was to develop such a method and for the first time assess the evolution of surface area of HA during biomimetic growth. The surface area of a TiO2-covered titanium substrate was measured prior to and following the biomimetic coating deposition using Ar gas adsorption at 77 K. The presence of HA on the surface was verified with scanning electron microscopy and X-ray diffraction. The specific surface area of the coating was found to increase linearly during 1 week of deposition at a rate of ∼100 cm2 day−1 (g substrate)−1. The presented method may be used as a tool for studying the evolution in surface area of coatings on solid substrates during biomimetic deposition or other growth processes.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-88439 (URN)10.1021/la803520k (DOI)000262827400007 ()19115807 (PubMedID)
    Tilgjengelig fra: 2009-02-02 Laget: 2009-02-02 Sist oppdatert: 2018-02-08bibliografisk kontrollert
    7. Multifunctional implant coatings providing possibilities for fast antibiotics loading with subsequent slow release
    Åpne denne publikasjonen i ny fane eller vindu >>Multifunctional implant coatings providing possibilities for fast antibiotics loading with subsequent slow release
    Vise andre…
    2009 (engelsk)Inngår i: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 20, nr 9, s. 1859-1867Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The possibility to fast-load biomimetic hydroxyapatite coatings on surgical implant with the antibiotics Amoxicillin, Gentamicin sulfate, Tobramycin and Cephalothin has been investigated in order to develop a multifunctional implant device offering sustained local anti-bacterial treatment and giving the surgeon the possibility to choose which antibiotics to incorporate in the implant at the site of surgery. Physical vapor deposition was used to coat titanium surfaces with an adhesion enhancing gradient layer of titanium oxide having an amorphous oxygen poor composition at the interface and a crystalline bioactive anatase TiO2 composition at the surface. Hydroxyapatite (HA) was biomimetically grown on the bioactive TiO2 to serve as a combined bone in-growth promoter and drug delivery vehicle. The coating was characterized using scanning and transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The antibiotics were loaded into the HA coatings via soaking and the subsequent release and antibacterial effect were analyzed using UV spectroscopy and examination of inhibition zones in a Staphylococcus aureus containing agar. It was found that a short drug loading time of 15 min ensured antibacterial effects after 24 h for all antibiotics under study. It was further found that the release processes of Cephalothin and Amoxicillin consisted of an initial rapid drug release that varied unpredictably in amount followed by a reproducible and sustained release process with a release rate independent of the drug loading times under study. Thus, implants that have been fast-loaded with drugs could be stored for ~10 min in a simulated body fluid after loading to ensure reproducibility in the subsequent release process. Calculated release rates and measurements of drug amounts remaining in the samples after 22 h of release indicated that a therapeutically relevant dose could be achieved close to the implant surface for about 2 days. Concluding, the present study provides an outline for the development of a fast-loading slow-release surgical implant kit where the implant and the drug are separated when delivered to the surgeon, thus constituting a flexible solution for the surgeon by offering the choice of quick addition of antibiotics to the implant coating based on the patient need.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-122095 (URN)10.1007/s10856-009-3749-6 (DOI)000268786400010 ()19399593 (PubMedID)
    Tilgjengelig fra: 2010-04-06 Laget: 2010-04-06 Sist oppdatert: 2018-02-08bibliografisk kontrollert
    8. Co-loading of bisphosphonates and antibiotics to a biomimetic hydroxyapatite coating
    Åpne denne publikasjonen i ny fane eller vindu >>Co-loading of bisphosphonates and antibiotics to a biomimetic hydroxyapatite coating
    2011 (engelsk)Inngår i: Biotechnology letters, ISSN 0141-5492, E-ISSN 1573-6776, Vol. 33, nr 6, s. 1265-1268Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    We have incorporated bisphosphonates and antibiotics simultaneously into a biomimetic hydroxyapatite implant coating aiming to use the interaction between drug-molecules and hydroxyapatite to enable local release of the two different substances to obtain a dual biological effect. A sustained release over for 43 h of antibiotics (cephalothin) was achieved without negative interference from the presence of the bisphosphonate (clodronate) which, in turn, successfully bonded to the coating surface. To our knowledge, this is the first study that indicates the possibility to simultaneously incorporate both antibiotics and bisphosphonates to an implant coating, a strategy that is believed to improve implant stability and reduce implant-related infections.

    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot nanoteknologi och funktionella material
    Identifikatorer
    urn:nbn:se:uu:diva-145824 (URN)10.1007/s10529-011-0542-7 (DOI)000291655200027 ()21287232 (PubMedID)
    Tilgjengelig fra: 2011-02-11 Laget: 2011-02-11 Sist oppdatert: 2018-02-08bibliografisk kontrollert
    9. In vitro characterization of bioactive titanium dioxide/hydroxyapatite surfaces functionalized with BMP-2
    Åpne denne publikasjonen i ny fane eller vindu >>In vitro characterization of bioactive titanium dioxide/hydroxyapatite surfaces functionalized with BMP-2
    Vise andre…
    2009 (engelsk)Inngår i: Journal of biomedical materials research. Part B, Applied biomaterials, ISSN 1552-4981, Vol. 91B, nr 2, s. 780-787Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Poor implant fixation and bone resorption are two of the major challenges in modern orthopedics and are caused by poor bone/implant integration. In this work, bioactive crystalline titanium dioxide (TiO(2))/hydroxyapatite (HA) surfaces, functionalized with bone morphogenetic protein 2 (BMP-2), were evaluated as potential implant coatings for improved osseointegration. The outer layer consisted of HA, which is known to be osteoconductive, and may promote improved initial bone attachment when functionalized with active molecules such as BMP-2 in a soaking process. The inner layer of crystalline TiO(2) is bioactive and ensures long-term fixation of the implant, once the hydroxyapatite has been resorbed. The in vitro response of mesenchymal stem cells on bioactive crystalline TiO(2)/HA surfaces functionalized with BMP-2 was examined and compared with the cell behavior on nonfunctionalized HA layers, crystalline TiO(2) surfaces, and native titanium oxide surfaces. The crystalline TiO(2) and the HA surfaces showed to be more favorable than the native titanium oxide surface in terms of cell viability and cell morphology as well as initial cell differentiation. Furthermore, cell differentiation on BMP-2-functionalized HA surfaces was found to be significantly higher than on the other surfaces indicating that the simple soaking process can be used for incorporating active molecules, promoting fast bone osseointegration to HA layers.

    Emneord
    biomimetic hydroxyapatite, growth factors, BMP-2, anatase titanium dioxide, mesenchymal stem cells, differentiation, viability, morphology
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot nanoteknologi och funktionella material
    Identifikatorer
    urn:nbn:se:uu:diva-108680 (URN)10.1002/jbm.b.31456 (DOI)000270868600034 ()19582842 (PubMedID)
    Tilgjengelig fra: 2009-09-26 Laget: 2009-09-26 Sist oppdatert: 2018-02-08bibliografisk kontrollert
    10. In Vivo Evaluation of Functionalized Biomimetic Hydroxyapatite for Local Delivery of Active Agents
    Åpne denne publikasjonen i ny fane eller vindu >>In Vivo Evaluation of Functionalized Biomimetic Hydroxyapatite for Local Delivery of Active Agents
    Vise andre…
    2011 (engelsk)Inngår i: Journal of Biomaterials and Nanobiotechnology, ISSN 2158-7027, 2158-7043, Vol. 2, nr 2, s. 149-154Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This study was carried out to investigate the biological response in vivo to biomimetic hydroxyapatite implant coatings functionalized with bisphosphonates and bone morphogenetic proteins. The functionalization was carried out by a simple soaking procedure in the operating room immediately prior to surgery. Cylindrical titanium samples with and without coatings were implanted in the distal femoral epiphysis of sheep and retrieved after 6 weeks. The histological analysis proved that all samples were integrated well in the tissue with no signs of intolerance. Fewer osteoclasts were observed in the vicinity of bisphosphonate-functionalized samples and the bone was denser around these samples compared to the other samples. Samples functionalized with bone morphogenetic protein induced more bone/implant contact but showed a more inconsistent outcome with reduced bone density around the samples. This study demonstrates a simple method to functionalize implant coatings, which provides surgeons with an option of patient-specific functionalization of implants. The observed biological impact due to the delivery of active molecules from the coatings suggests that this strategy may also be employed to deliver antibiotics from similar coatings.

    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot materialvetenskap; Teknisk fysik med inriktning mot nanoteknologi och funktionella material; Kemi med inriktning mot polymerkemi
    Identifikatorer
    urn:nbn:se:uu:diva-156129 (URN)10.4236/jbnb.2011.22019 (DOI)
    Forskningsfinansiär
    Swedish Research Council
    Tilgjengelig fra: 2011-07-11 Laget: 2011-07-11 Sist oppdatert: 2018-02-08bibliografisk kontrollert
    11. A novel method for local administration of strontium from implant surfaces
    Åpne denne publikasjonen i ny fane eller vindu >>A novel method for local administration of strontium from implant surfaces
    2010 (engelsk)Inngår i: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 21, nr 5, s. 1605-1609Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This study proves that a film of Strontianite (SrCO(3)) successfully can be formed on a bioactive surface of sodium titanate when exposed to a strontium acetate solution. This Strontianite film is believed to enable local release of strontium ions from implant surfaces and thus stimulate bone formation in vivo. Depending on the method, different types of films were achieved with different release rates of strontium ions, and the results points at the possibility to tailor the rate and amount of strontium that is to be released from the surface. Strontium has earlier been shown to be highly involved in the formation of new bone as it stimulates the replication of osteoblasts and decreases the activity of osteoclasts. The benefit of strontium has for example been proved in studies where the number of vertebral compression fractures in osteoporotic persons was drastically reduced in patients receiving therapeutical doses of strontium. Therefore, it is here suggested that the bone healing process around an implant may be improved if strontium is administered locally at the site of the implant. The films described in this paper were produced by a simple immersion process where alkali treated titanium was exposed to an aqueous solution containing strontium acetate. By heating the samples at different times during the process, different release rates of strontium ions were achieved when the samples were exposed to simulated body fluid. The strontium containing films also promoted precipitation of bone like apatite when exposed to a simulated body fluid.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-125407 (URN)10.1007/s10856-010-4022-8 (DOI)000277603000023 ()20162327 (PubMedID)
    Tilgjengelig fra: 2010-05-18 Laget: 2010-05-18 Sist oppdatert: 2018-02-08bibliografisk kontrollert
  • 172.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Andersson, Mattias
    Nilsson, Peter
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mesoporous Calcium Carbonate as a Phase Stabilizer of Amorphous Celecoxib - An Approach to Increase the Bioavailability of Poorly Soluble Pharmaceutical Substances.2013Inngår i: Advanced healthcare materials, ISSN 2192-2640, Vol. 2, nr 11, s. 1469-1476Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The bioavailability of crystalline pharmaceutical substances is often limited by their poor aqueous solubility but it can be improved by formulating the active substance in the amorphous state that is featured with a higher apparent solubility. Although the possibility of stabilizing amorphous drugs inside nano-sized pores of carbon nanotubes and ordered mesoporous silica has been shown, no conventional pharmaceutical excipients have so far been shown to possess this property. This study demonstrates the potential of using CaCO3 , a widely used excipient in oral drug formulations, to stabilize the amorphous state of active pharmaceutical ingredients, in particular celecoxib. After incorporation of celecoxib in the vaterite particles, a five to sixfold enhancement in apparent solubility of celecoxib is achieved due to pore-induced amorphization. To eliminate the possibility of uncontrolled phase transitions, the vaterite particles were stored in an inert atmosphere at 5 °C throughout the study. Also, to demonstrate that the amorphization effect was indeed associated with vaterite mesopores, accelerated stress conditions of 100% relative humidity was employed to impose transition from mesoporous vaterite to an essentially non-porous aragonite phase of CaCO3 , which shows only limited amorphization ability. Further, an improvement in solubility was also confirmed for ketoconazole when formulated with the mesoporous vaterite. Synthesis of the carrier particles and the incorporation of the active substances were carried out simultaneously in a one-step procedure, enabling easy fabrication. These results represent a promising approach to achieve enhanced bioavailability in new formulations of Type II BCS drugs.

  • 173.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Brohede, Ulrika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Fast loading, slow release: a new strategy for incorporating antibiotics2009Inngår i: Key Engineering Materials, ISSN 1662-9795, Vol. 396-398, s. 523-526Artikkel i tidsskrift (Fagfellevurdert)
  • 174.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Brohede, Ulrika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Fast loading, slow release a new strategy for incorporating antibiotics to hydroxyapatite2008Inngår i: Bioceramics 21, 2008Konferansepaper (Fagfellevurdert)
  • 175.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Brohede, Ulrika
    Sandvik AB, Stockholm.
    Piskounova, Sonya
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Polymerkemi.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Larsson, Sune
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Ortopedi.
    Maria, Strømme
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    In Vivo Evaluation of Functionalized Biomimetic Hydroxyapatite for Local Delivery of Active Agents2011Inngår i: Journal of Biomaterials and Nanobiotechnology, ISSN 2158-7027, 2158-7043, Vol. 2, nr 2, s. 149-154Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study was carried out to investigate the biological response in vivo to biomimetic hydroxyapatite implant coatings functionalized with bisphosphonates and bone morphogenetic proteins. The functionalization was carried out by a simple soaking procedure in the operating room immediately prior to surgery. Cylindrical titanium samples with and without coatings were implanted in the distal femoral epiphysis of sheep and retrieved after 6 weeks. The histological analysis proved that all samples were integrated well in the tissue with no signs of intolerance. Fewer osteoclasts were observed in the vicinity of bisphosphonate-functionalized samples and the bone was denser around these samples compared to the other samples. Samples functionalized with bone morphogenetic protein induced more bone/implant contact but showed a more inconsistent outcome with reduced bone density around the samples. This study demonstrates a simple method to functionalize implant coatings, which provides surgeons with an option of patient-specific functionalization of implants. The observed biological impact due to the delivery of active molecules from the coatings suggests that this strategy may also be employed to deliver antibiotics from similar coatings.

  • 176.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Brohede, Ulrika
    Sandvik AB, Stockholm.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Co-loading of bisphosphonates and antibiotics to a biomimetic hydroxyapatite coating2011Inngår i: Biotechnology letters, ISSN 0141-5492, E-ISSN 1573-6776, Vol. 33, nr 6, s. 1265-1268Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have incorporated bisphosphonates and antibiotics simultaneously into a biomimetic hydroxyapatite implant coating aiming to use the interaction between drug-molecules and hydroxyapatite to enable local release of the two different substances to obtain a dual biological effect. A sustained release over for 43 h of antibiotics (cephalothin) was achieved without negative interference from the presence of the bisphosphonate (clodronate) which, in turn, successfully bonded to the coating surface. To our knowledge, this is the first study that indicates the possibility to simultaneously incorporate both antibiotics and bisphosphonates to an implant coating, a strategy that is believed to improve implant stability and reduce implant-related infections.

  • 177.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    A novel method for local administration of strontium from implant surfaces2010Inngår i: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 21, nr 5, s. 1605-1609Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study proves that a film of Strontianite (SrCO(3)) successfully can be formed on a bioactive surface of sodium titanate when exposed to a strontium acetate solution. This Strontianite film is believed to enable local release of strontium ions from implant surfaces and thus stimulate bone formation in vivo. Depending on the method, different types of films were achieved with different release rates of strontium ions, and the results points at the possibility to tailor the rate and amount of strontium that is to be released from the surface. Strontium has earlier been shown to be highly involved in the formation of new bone as it stimulates the replication of osteoblasts and decreases the activity of osteoclasts. The benefit of strontium has for example been proved in studies where the number of vertebral compression fractures in osteoporotic persons was drastically reduced in patients receiving therapeutical doses of strontium. Therefore, it is here suggested that the bone healing process around an implant may be improved if strontium is administered locally at the site of the implant. The films described in this paper were produced by a simple immersion process where alkali treated titanium was exposed to an aqueous solution containing strontium acetate. By heating the samples at different times during the process, different release rates of strontium ions were achieved when the samples were exposed to simulated body fluid. The strontium containing films also promoted precipitation of bone like apatite when exposed to a simulated body fluid.

  • 178.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    A novel surface modification enabling local administration of strontium from implants2010Konferansepaper (Fagfellevurdert)
  • 179.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Frykstrand, Sara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Grandfield, Kathryn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    A Template-Free, Ultra-Adsorbing, High Surface Area Carbonate Nanostructure2013Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, nr 7, s. e68486-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report the template-free, low-temperature synthesis of a stable, amorphous, and anhydrous magnesium carbonate nanostructure with pore sizes below 6 nm and a specific surface area of ~ 800 m2 g−1, substantially surpassing the surface area of all previously described alkali earth metal carbonates. The moisture sorption of the novel nanostructure is featured by a unique set of properties including an adsorption capacity ~50% larger than that of the hygroscopic zeolite-Y at low relative humidities and with the ability to retain more than 75% of the adsorbed water when the humidity is decreased from 95% to 5% at room temperature. These properties can be regenerated by heat treatment at temperatures below 100°C.The structure is foreseen to become useful in applications such as humidity control, as industrial adsorbents and filters, in drug delivery and catalysis.

  • 180.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Frykstrand, Sara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Zhang, Peng
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Porous alkali earth metal carbonates as enhancers of solubility for poorly soluble drugs2015Inngår i: Nanotechnologies in Drug Delivery, London 2015, 2015Konferansepaper (Fagfellevurdert)
  • 181.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Hoess, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Ott, Marjam
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Maria, Strømme
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    A Soluble Strontium Carbonate Implant Coating for Local and Targeted Cell Stimulation2011Inngår i: MRS Spring Meeeting 2011, 2011Konferansepaper (Fagfellevurdert)
  • 182.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Jämstorp, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Bredenberg, Susanne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    A ceramic drug delivery vehicle for oral administration of highly potent opioids2010Inngår i: Journal of Pharmaceutical Sciences, ISSN 0022-3549, E-ISSN 1520-6017, Vol. 99, nr 1, s. 219-226Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pellets composed of the ceramic material Halloysite and microcrystalline cellulose were synthesized with the aim of producing a drug delivery vehicle for sustained release of the opioid Fentanyl with low risk for dose dumping at oral intake of the highly potent drug. Drug release profiles of intact and crushed pellets, to simulate swallowing without or with chewing, in pH 6.8, pH 1, and in 48% ethanol were recorded in order to replicate the conditions in the small intestines, in the stomach, as well as cointake of the drug with alcohol. The drug release was analyzed by employing the Weibull equation, which showed that the release profiles were either governed by fickian diffusion (intact pellets in pH 6.8 and in ethanol) or by diffusion in a fractal or disordered pore network (intact pellets in pH 1 and crushed pellets in all solutions). A sustained release for approximately 3-4 h was obtained in all studied solutions from intact pellets, whereas crushed pellets released the drug content during approximately 2-3 h. The finding that a sustained release profile could be obtained both in alcohol and after crushing of the pellets, shows that the ceramic carrier under investigation, at least to some extent, hampers dose dumping, and may thus be a promising material in future developments of new opioid containing oral dosage forms.

  • 183.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Lilja, Mirjam
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Åstrand, Maria
    Sandvik AB.
    Maria, Strømme
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Welch, Ken
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Photocatalytic and antimicrobial properties of a TiO2 implant coating deposited through cathodic arc evaporation2012Inngår i: European Cells and Materials, ISSN 1473-2262, E-ISSN 1473-2262, Vol. 23, nr Suppl. 5, s. 36-Artikkel i tidsskrift (Fagfellevurdert)
  • 184.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Lilja, Mirjam
    Nanoteknologi och funktionella material, Nanotechnology and Functional Materials.
    Åstrand, Maria
    Sandvik Sverige AB.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Welch, Ken
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Photocatalytic and antimicrobial properties of a TiO2 implant coating deposited through cathodic arc evaporation2012Inngår i: Scandinavian Society of Biomaterials, Uppsala, Sweden, May 2012, 2012Konferansepaper (Fagfellevurdert)
  • 185.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Paz, Loli
    Vigo University, Spain.
    Léon, Betty
    Vigo University, Spain.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    A rapid method to improve the biological response to titanium by laser induced conversion of Ti4+ to Ti3+ sites in titanium oxide surfaces.2010Inngår i: Sicot/Sirot - Ortopediveckan 2010, 2010Konferansepaper (Fagfellevurdert)
  • 186.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Paz, María Dolores
    León, Betty
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Laser induced surface structuring and ion conversion in the surface oxide of titanium: possible implications for the wetability of laser treated implants.2013Inngår i: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 24, nr 1, s. 11-15Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present study, commercially pure titanium was irradiated with UV-light with varying wavelengths using a Q-switched Nd:YAG-laser. This was performed in order to investigate if a laser treatment can be employed to rapidly introduce hydrophilic properties to titanium surfaces, which is believed to facilitate protein adsorption and cell attachment. It was demonstrated that irradiation with 355 nm light (10 Hz, 90 mJ/shot) for 1 min or more caused an ion conversion of Ti(4+) to Ti(3+) sites in the surface oxide which lead to an increase in hydrophilicity of the surface. Furthermore, shorter irradiation times at 355 nm caused a surface structuring that gave rise to an unexpected and unstable hydrophobic state at the surface. Irradiation with 266 nm light (10 Hz, 40 mJ/shot) did not introduce any ion conversion in the surface oxide, nor did it give rise to any hydrophobicity of the surface.

  • 187.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Teknisk-naturvetenskapliga fakulteten. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Pedersen, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Maria, Strømme
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Adjustable nanostructure of synthetic geopolymers enables tunable and sustained release of oxycodoneArtikkel i tidsskrift (Fagfellevurdert)
  • 188.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Pedersen, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Sustained Drug Release from Mesoporous Geopolymers2011Inngår i: MRS Spring Meeting and Exhibit 2011, 2011Konferansepaper (Fagfellevurdert)
  • 189.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Pedersen, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Synthetic geopolymers for controlled delivery of oxycodone: Adjustable and nanostructured porosity enables tunable and sustained drug release2011Inngår i: PLoS ONE, ISSN 1932-6203, Vol. 6, nr 3, s. e17759-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article we for the first time present a fully synthetic mesoporous geopolymer drug carrier for controlled release of opioids. Nanoparticulate precursor powders with different Al/Si-ratios were synthesized by a sol-gel route and used in the preparation of different geopolymers, which could be structurally tailored by adjusting the Al/Si-ratio and the curing temperatures. In particular, it was shown that the pore sizes of the geopolymers decreased with increasing Al/Si ratio and that completely mesoporous geopolymers could be produced from precursor particles with the Al/Si ratio 2:1. The mesoporosity was shown to be associated with a sustained and linear in vitro release profile of the opioid oxycodone. A clinically relevant release period of about 12 h was obtained by adjusting the size of the pellets. The easily fabricated and tunable geopolymers presented in this study constitute a novel approach in the development of controlled release formulations, not only for opioids, but whenever the clinical indication is best treated with a constant supply of drugs and when the mechanical stability of the delivery vehicle is crucial.

  • 190.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Svahn, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jarmar, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Formation and adhesion of biomimetic hydroxyapatite deposited on titanium substrates2007Inngår i: Acta Biomaterialia, ISSN 1742-7061, Vol. 3, nr 6, s. 980-984Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study has been carried out to investigate the bioactivity of rutile and to deposit hydroxyapatite (HA) on heat-treated titanium through a biomimetic method. Biomimetic deposition of HA has gained large interest because of its low deposition temperature and good step coverage; however, it demands a substrate with bioactive properties. Commercially pure titanium is not bioactive but it can acquire bioactive properties through various surface treatments. In the present study, titanium plates were heat-treated at 800 °C to achieve rutile TiO2 surfaces. These samples were immersed in a phosphate-buffered saline solution for seven days in order to deposit a HA layer on the surface. The rutile TiO2 surfaces were found to be highly bioactive: after seven days of immersion, a layer of HA several micrometers thick covered the plates. The HA surfaces were confirmed by electron microscopy and X-ray diffraction. A scratch test was used to assess the adhesion of the HA coatings. This is a standard method to provide a measure of the coating-to-substrate adhesion and was found to be a useful method to test the thin HA coatings deposited on the bioactive surfaces. The critical pressure of the layer was estimated to be 2.4 ± 0.1 GPa.

  • 191.
    Forsgren, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Svahn, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Jarmar, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Structural change of biomimetic hydroxyapatite coatings due to heat treatment2007Inngår i: Journal of Applied Biomaterials & Biomechanics, ISSN 1722-6899, Vol. 5, nr 1, s. 23-27Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biomimetic deposition of hydroxyapatite (HA) coatings on implants could be done for two reasons, one is to study their possible bioactivity, and one is to generate bioactive coatings on implants before implantation surgery to improve the osseointegration. Heat treatment of coated implants can be performed for several reasons, for example, to ensure coating sterility and to increase the adhesion. This paper describes the morphology and crystalline structure changes occurring due to the heat treatment of biomimetic HA coatings on rutile TiO2. Rutile TiO2 surfaces were produced on titanium (Ti) plates by heating at 800 C. Afterwards, these samples were immersed in a phosphate buffer saline solution for 7 days at 37 C in order to deposit HA coatings on their surfaces. These HA coatings were then either untreated or heat treated at 600 or 800 C for 1 hr. The coatings microstructural changes were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Cross-sectional TEM samples were produced using a sample preparation method based on focused ion beam microscopy (FIB). Rutile was found to be bioactive due to HA formation on the surface. The 600 C heat treatment of the HA coating changed its morphology, increased its grain size and also increased the porosity. At 800 C the coating was completely transformed to beta-TCP according to XRD. Sample preparation using FIB and TEM analysis proved to be a useful method for high-resolution analysis of biomimetic coatings in cross-section.

  • 192.
    Frenning, Göran
    et al.
    Uppsala universitet, Medicinska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material. Galenisk farmaci.
    Nilsson, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material. Nanoteknologi och funktionella material.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material. Nanoteknologi och funktionella material.
    A generalized regular singular-point description of low-frequency dielectric responses2004Inngår i: Phys. Rev. B, Vol. 70, s. 012506-1Artikkel i tidsskrift (Fagfellevurdert)
  • 193.
    Frykstrand, Sara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Nanoporösa material2014Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 194.
    Frykstrand, Sara
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Forsgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Cheung, Ocean
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Zhang, Peng
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Hong, Jaan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Klinisk immunologi.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Ferraz, Natalia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Study of mesoporous magnesium carbonate in contact with whole human blood2016Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, nr 58, s. 52810-52816Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The interaction of mesoporours magnesium carbonate (Upsalite) particles (50-100 mm) with human whole blood was investigated using an in vitro loop model and the effect on the complement system, blood coagulation and red blood cell lysis was assessed. The removal of Ca2+ by Upsalite and the possible exchange with and/or release of Mg2+ were explored as well. Upsalite was found to present anticoagulant properties, most probably due to the uptake of Ca2+ by the particles. No hemolytic activity was detected at Upsalite concentrations up to 1 mg ml(-1). Moderate to high levels of C3a and sC5b-9 were observed for Upsalite, however such levels were statistically different from the negative control only when the particle concentrations were 0.25 mg ml(-1) and 1.0 mg ml(-1), respectively. The presented findings are promising for the future development of mesoporous magnesium carbonate-based materials for biomedical applications.

  • 195.
    Frykstrand, Sara
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Forsgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Ferraz, Natalia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Synthesis and potential of Upsalite: a Mesoporous magnesium carbonate synthesized without surfactants2015Inngår i: Uppsala Biomaterials Conference, 2015Konferansepaper (Fagfellevurdert)
  • 196.
    Frykstrand, Sara
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Forsgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Ferraz, Natalia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Synthesis and potential of Upsalite®: a mesoporous magnesium carbonate synthesized without surfactants2015Inngår i: Fourth International Conference on Multifunctional, Hybrid and Nanomaterials: Hybrid Materials 2015, Stiges, 2015, s. P1.225-Konferansepaper (Fagfellevurdert)
  • 197.
    Frykstrand, Sara
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Forsgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    On the pore forming mechanism of Upsalite, a micro- and mesoporous magnesium carbonate2014Inngår i: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 190, s. 99-104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work analyzes the pore forming mechanism and stability of Upsalite; an extraordinary moisture absorbing, high-surface area magnesium carbonate powder synthesised without the use of surfactants as pore forming agents. The pores in Upsalite were found to be created in a two-step process where the first step includes the formation of micropores by solvent evaporation and release of physically bound carbon dioxide, acting as an in-situ pore-forming template. In the second step, the micropores expand to mesopores due to partial decomposition of organic groups on the surface of the pore walls when the material is stored in air at moderate temperatures (70 °C). The resulting material has a narrow pore size distribution centered at 5 nm, and the amorphous structure is stable upon storage in a humid atmosphere.

    It was further shown that calcination at temperatures above 250 °C is required for complete removal of the organic surface groups in Upsalite. Prior to calcination, the organic groups present in the material act as barriers hindering water to induce crystallization of the bulk material. After calcination, however, Upsalite crystallizes into nesquehonite when stored at 100 % relative humidity for several days. The results presented herein are expected to be useful for the development of novel surfactant-free synthesis routes of porous materials as well as for the understanding of the long-term performance of such materials.

  • 198.
    Frykstrand, Sara
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Forsgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    On the use of gas as a pore forming agent in mesoporous materials2014Konferansepaper (Annet vitenskapelig)
  • 199.
    Frykstrand, Sara
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Forsgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    The formation of UpsaliteTM: A template-free micro- and mesoporous amorphous magnesium carbonate2013Konferansepaper (Fagfellevurdert)
  • 200.
    Frykstrand, Sara
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Forsgren, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Mihranyan, Albert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Strømme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Upsalite®: A template-free micro- and  mesoporous amorphous magnesium carbonate2014Konferansepaper (Fagfellevurdert)
1234567 151 - 200 of 1135
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