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Pochard, I., Vall, M., Eriksson, J., Farineau, C., Cheung, O., Frykstrand, S., . . . Strömme, M. (2018). Amine-functionalised mesoporous magnesium carbonate: Dielectric spectroscopy studies of interactions with water and stability. Materials Chemistry and Physics, 216, 332-338
Open this publication in new window or tab >>Amine-functionalised mesoporous magnesium carbonate: Dielectric spectroscopy studies of interactions with water and stability
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2018 (English)In: Materials Chemistry and Physics, ISSN 0254-0584, E-ISSN 1879-3312, Vol. 216, p. 332-338Article in journal (Refereed) Published
Abstract [en]

A mesoporous magnesium carbonate (MMC) material that was first described in 2013 is currently being investigated for several industrial and life-science-based applications. In this paper, the effect of functionalising the surface of MMC with amine groups on the water interaction properties of the material is investigated in detail. Amine functionalisation enhanced the stability and water sorption-release properties of the material. This is explained by the low affinity between amine-functionalised MMC and water molecules, as attested by the high free/total water ratio shown by dielectric spectroscopy. This low affinity had an impact on the total amount of adsorbed water at low relative humidities (RHs) but not at high RHs. The functionalisation of MMC with amine groups also stabilised the material in moist environments, hindering spontaneous crystallisation. These results provide a more fundamental understanding of the water interaction properties of MMC and are also expected to facilitate optimisation of the stability of materials like this for novel drug formulations and other life-science applications, as well as for their use in humidity control.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2018
Keywords
Magnesium carbonate, Mesoporous, Amine functionalisation, Moisture, Dielectric spectroscopy
National Category
Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-362476 (URN)10.1016/j.matchemphys.2018.05.053 (DOI)000441492000044 ()
Funder
Swedish Research Council, 2014-3929
Available from: 2018-10-05 Created: 2018-10-05 Last updated: 2018-10-09Bibliographically approved
Yang, J., Alvebratt, C., Lu, X., Bergström, C. A. .., Strömme, M. & Welch, K. (2018). Amorphous magnesium carbonate nanoparticles with strong stabilizing capability for amorphous ibuprofen. International Journal of Pharmaceutics, 548(1), 515-521
Open this publication in new window or tab >>Amorphous magnesium carbonate nanoparticles with strong stabilizing capability for amorphous ibuprofen
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2018 (English)In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 548, no 1, p. 515-521Article in journal (Refereed) Published
Keywords
Magnesium carbonate, Nanoparticles, Nanocomposite, Amorphous, Ibuprofen, Solubility, Dissolution
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-358027 (URN)
Available from: 2018-08-23 Created: 2018-08-23 Last updated: 2018-08-23
Janson, O., Strømme, M., Engqvist, H. & Welch, K. (2018). Debridement of Bacterial Biofilms with TiO2/H2O2 Solutions and Visible Light Irradiation. International Journal of Biomaterials, 2018, Article ID 5361632.
Open this publication in new window or tab >>Debridement of Bacterial Biofilms with TiO2/H2O2 Solutions and Visible Light Irradiation
2018 (English)In: International Journal of Biomaterials, ISSN 1687-8787, E-ISSN 1687-8795, Vol. 2018, article id 5361632Article in journal (Refereed) Published
Abstract [en]

Objectives. The aim of the study was to explore the debridement efficacy of different solutions of H2O2 and rutile particles against Staphylococcus epidermidis and Pseudomonas aeruginosa biofilms attached to titanium surfaces when exposed to visible light. Materials and Methods. Titanium discs cultivated with biofilms of Staphylococcus epidermidis or Pseudomonas aeruginosa were subjected for 1 min to suspensions consisting of rutile particles mixed with high (950 mM) or low (2 mM) concentrations of H2O2 under visible light irradiation (405 nm; 2.1 mW/cm2). Discs were rinsed and the degree of debridement was determined through scanning electron microscopy and viability assessment of the remaining bacteria using luminescence measurements and/or a metabolic activity assay. Results. Cleaning mixtures containing the higher concentration of H2O2 showed a significantly improved debridement compared to the negative control in all experiments. The addition of rutile particles was shown to have a statistically significant effect in one test with S. epidermidis. Limited evidence of the catalytic effect of visible light irradiation was seen, but effects were relatively small and statistically insignificant. Conclusions. H2O2 at a concentration of 950 mM proved to be the strongest contribution to the debridement and bactericidal effect of the cleaning techniques tested in this study.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2018
National Category
Nano Technology Biomaterials Science
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials; Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-355674 (URN)10.1155/2018/5361632 (DOI)000438846900001 ()30057613 (PubMedID)
Funder
VINNOVA, E!8320
Available from: 2018-07-03 Created: 2018-07-03 Last updated: 2018-09-26Bibliographically approved
Basu, A., Heitz, K., Strömme, M., Welch, K. & Ferraz, N. (2018). Ion-crosslinked wood-derived nanocellulose hydrogels with tunable antibacterial properties: Candidate materials for advanced wound care applications. Carbohydrate Polymers, 181, 345-350
Open this publication in new window or tab >>Ion-crosslinked wood-derived nanocellulose hydrogels with tunable antibacterial properties: Candidate materials for advanced wound care applications
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2018 (English)In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 181, p. 345-350Article in journal (Refereed) Published
Abstract [en]

Development of advanced dressings with antimicrobial properties for the treatment of infected wounds is an important approach in the fight against evolution of antibiotic resistant bacterial strains. Herein, the effects of ion-crosslinked nanocellulose hydrogels on bacteria commonly found in infected wounds were investigated in vitro. By using divalent calcium or copper ions as crosslinking agents, different antibacterial properties against the bacterial strains Staphylococcus epidermidis and Pseudomonas aeruginosa were obtained. Calcium crosslinked hydrogels were found to retard S. epidermidis growth (up to 266% increase in lag time, 36% increase in doubling time) and inhibited P. aeruginosa biofilm formation, while copper crosslinked hydrogels prevented S. epidermidis growth and were bacteriostatic towards P. aeruginosa (49% increase in lag time, 78% increase in doubling time). The wound dressing candidates furthermore displayed barrier properties towards both S. epidermidis and P. aeruginosa, hence making them interesting for further development of advanced wound dressings with tunable antibacterial properties.

Keywords
Nanofibrillated cellulose, Biofilm, Wound dressing, Infected wound
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-333382 (URN)10.1016/j.carbpol.2017.10.085 (DOI)000418661000041 ()29253982 (PubMedID)
Funder
Swedish Research Council Formas
Available from: 2017-11-13 Created: 2017-11-13 Last updated: 2018-10-12Bibliographically approved
Zhang, X., Welch, K., Tian, L., Johansson, M. B., Häggman, L., Liu, J. & Johansson, E. M. (2017). Enhanced charge carrier extraction by a highly ordered wrinkled MgZnO thin film for colloidal quantum dot solar cells. Journal of Materials Chemistry C, 5(42), 11111-11120
Open this publication in new window or tab >>Enhanced charge carrier extraction by a highly ordered wrinkled MgZnO thin film for colloidal quantum dot solar cells
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2017 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 5, no 42, p. 11111-11120Article in journal (Refereed) Published
Abstract [en]

Efficient charge carrier extraction from a colloidal quantum dot (CQD) solid is crucial for highperformance of CQD solar cells (CQDSCs). Herein, highly ordered wrinkled MgZnO (MZO) thin films aredemonstrated to improve the charge carrier extraction of PbS CQDSCs. The highly ordered wrinkledMZO thin films are prepared using a low-temperature combustion method. The photovoltaicperformances of CQDSCs with a combustion-processed MZO (CP-MZO) thin film as an electrontransport material (ETM) are compared to those of CQDSCs with a conventional sol–gel processed MZO(SGP-MZO) thin film as an ETM. We performed photoluminescence quenching measurements of thecolloidal quantum dot (CQD) solid and charge carrier dynamic analysis of full solar cell devices. Theresults show that the highly ordered wrinkled CP-MZO thin film significantly increases the chargecarrier extraction from the CQD solid and therefore diminishes the charge interfacial recombination atthe CQD/ETM junction, leading to a 15.5% increase in power conversion efficiency. The improvedefficiency in the CP-MZO based CQDSC is also attributed to the compact and pin-hole free CP-MZOthin film.

National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-337927 (URN)10.1039/C7TC02740K (DOI)000414359500026 ()
Funder
Swedish Research CouncilSwedish Research Council FormasSwedish Energy AgencyGöran Gustafsson Foundation for Research in Natural Sciences and MedicineÅForsk (Ångpanneföreningen's Foundation for Research and Development)
Available from: 2018-01-05 Created: 2018-01-05 Last updated: 2018-02-07Bibliographically approved
Yang, J., Alvebratt, C., Zhang, P., Zardán Gómez de la Torre, T., Strömme, M., Bergström, C. & Welch, K. (2017). Enhanced release of poorly water-soluble drugs from synergy between mesoporous magnesium carbonate and polymers. International Journal of Pharmaceutics, 525(1), 183-190
Open this publication in new window or tab >>Enhanced release of poorly water-soluble drugs from synergy between mesoporous magnesium carbonate and polymers
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2017 (English)In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 525, no 1, p. 183-190Article in journal (Refereed) Published
Abstract [en]

The need to combat poor water solubility has increased interest in supersaturating drug delivery systems. In this study, amorphous mesoporous magnesium carbonate (MMC) was used as a drug carrier to achieve supersaturation of tolfenamic acid and rimonabant, two drug compounds with low aqueous solubility. The potential synergy between MMC and hydroxypropyl methylcellulose (HPMC), a polymer commonly included as a precipitation inhibitor in drug delivery systems, was explored with the aim of extending the time that high supersaturation levels were maintained. Release was studied under physiological conditions using USP-2 dissolution baths. A new small-scale method was developed to enable measurement of the initial drug release occurring when the MMC is immersed in the water phase. It was shown that MMC and HPMC together resulted in significant supersaturation and that the polymer enabled both the achievement of a higher API concentration and extension of the supersaturation period. The new small-scale release method showed that the release was linearly increasing with the dose and that similar release rates were observed for the two model compounds. It was hence concluded that the MMC release was diffusion limited for the compounds explored.

Keywords
Magnesium carbonate, Mesoporous, Hydroxypropyl methylcellulose, Tolfenamic acid, Rimonabant, Supersaturation
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-320987 (URN)10.1016/j.ijpharm.2017.04.018 (DOI)000401112300019 ()28396244 (PubMedID)
Funder
VINNOVASwedish Research Council
Available from: 2017-04-27 Created: 2017-04-27 Last updated: 2018-09-03Bibliographically approved
Janson, O., Unosson, E., Strömme, M., Engqvist, H. & Welch, K. (2017). Organic degradation potential of a TiO2/H2O2/UV-Vis system for dental applications. Journal of Dentistry, 67, 53-57
Open this publication in new window or tab >>Organic degradation potential of a TiO2/H2O2/UV-Vis system for dental applications
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2017 (English)In: Journal of Dentistry, ISSN 0300-5712, E-ISSN 1879-176X, Vol. 67, p. 53-57Article in journal (Refereed) Published
Abstract [en]

Objectives

The combination of TiO2 and H2O2 under light activation constitutes a promising method for disinfection of dental prosthetics and implants, due to production of reactive oxygen species (ROS). The aim of this work was to investigate the organic degradation ability of TiO2 particles in combination with H2O2 and under light activation utilizing the organic dye rhodamine B (RhB).

Methods

Five different types of TiO2 particles, consisting of anatase, rutile, or a mixture of these crystalline phases, were combined with H2O2 and RhB, and subsequently exposed to UV (365 nm) or visible (405 nm) light at an irradiance of 2.1 mW/cm2.

Results

It was found that rutile in combination with low concentrations of H2O2 (1.0–3.5 mM) resulted in a degradation of RhB of 96% and 77% after 10 min exposure to 365 nm and 405 nm light, respectively, which was the highest degradation of all test groups. Control measurements performed without light irradiation or irradiation at 470 nm, or without TiO2 particles resulted in little or no degradation of RhB.

Conclusions

Low H2O2 concentrations (1.0 mM–3.5 mM) and visible light (405 nm) used in combination with rutile TiO2 particles showed the highest RhB degradation capacity.

Clinical significance

A combination of TiO2 particles and H2O2 exposed to low energy UV or high energy visible light has an organic degradation capability that could be utilized in applications to kill or inactivate bacteria on medical devices such as dental implants for treatment against, e.g., peri-implantitis.

Keywords
TiO, HO, Reactive oxygen species, Rhodamine B, Rutile
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-330202 (URN)10.1016/j.jdent.2017.09.001 (DOI)000417204800007 ()28886983 (PubMedID)
Funder
VINNOVA, E!8320
Available from: 2017-09-27 Created: 2017-09-27 Last updated: 2018-08-27Bibliographically approved
Soininen, A. J., Appavou, M.-S., Frykstrand, S., Welch, K., Khaneft, M., Kriele, A., . . . Wuttke, J. (2016). Dynamics of water confined in mesoporous magnesium carbonate. Paper presented at 2016/12/15. Journal of Chemical Physics, 145(23), Article ID 234503.
Open this publication in new window or tab >>Dynamics of water confined in mesoporous magnesium carbonate
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2016 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 145, no 23, article id 234503Article in journal (Refereed) Published
Abstract [en]

We have measured the dynamics of water confined in a porous magnesium carbonate material, Upsalite (R), using the high-resolution neutron backscattering spectrometer SPHERES. We found quasielastic scattering that does not flatten out up to 360 K, which means that the dynamics of water are much slower than in other matrix materials. Specifically, a single Lorentzian line could be fitted to the quasielastic part of the acquired spectra between 220 and 360 K. This, accompanied by an elastic line from dynamically frozen water present at all experimental temperatures, even above the melting point, signaled a significant amount of bound or slow water.

National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-310427 (URN)10.1063/1.4971285 (DOI)000391688900028 ()27984867 (PubMedID)
Conference
2016/12/15
Funder
Swedish Research CouncilVINNOVA
Available from: 2016-12-15 Created: 2016-12-15 Last updated: 2017-11-29Bibliographically approved
Unosson, E., Morgenstern, M., Engqvist, H. & Welch, K. (2016). In vitro antibacterial properties and UV induced response from Staphylococcus epidermidis on Ag/Ti oxide thin films. Journal of materials science. Materials in medicine, 27(3), Article ID 49.
Open this publication in new window or tab >>In vitro antibacterial properties and UV induced response from Staphylococcus epidermidis on Ag/Ti oxide thin films
2016 (English)In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 27, no 3, article id 49Article in journal (Refereed) Published
Abstract [en]

Implanted materials are susceptible to bacterial colonization and biofilm formation, which can result in severe infection and lost implant function. UV induced photocatalytic disinfection on TiO2 and release of Ag+ ions are two promising strategies to combat such events, and can be combined for improved efficiency. In the current study, a combinatorial physical vapor deposition technique was utilized to construct a gradient coating between Ag and Ti oxide, and the coating was evaluated for antibacterial properties in darkness and under UV light against Staphylococcus epidermidis. The findings revealed a potent antibacterial effect in darkness due to Ag+ release, with near full elimination (97%) of viable bacteria and visible cell lysis on Ag dominated surfaces. The photocatalytic activity, however, was demonstrated poor due to low TiO2 crystallinity, and UV light irradiation of the coating did not contribute to the antibacterial effect. On the contrary, bacterial viability was in several instances higher after UV illumination, proposing a UV induced SOS response from the bacteria that limited the reduction rate during Ag+ exposure. Such secondary effects should thus be considered in the development of multifunctional coatings that rely on UV activation. 

Keywords
Silver; Titanium; UV; Antibacterial; SOS response; S. epidermidis
National Category
Medical Materials Materials Engineering Nano Technology
Research subject
Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-249179 (URN)10.1007/s10856-015-5662-5 (DOI)000368728100007 ()26758896 (PubMedID)
Projects
ProViking EBM
Funder
Swedish Foundation for Strategic Research
Available from: 2015-04-12 Created: 2015-04-12 Last updated: 2018-02-08Bibliographically approved
Welch, K., Latifzada, M. A., Frykstrand, S. & Strømme, M. (2016). Investigation of the Antibacterial Effect of Mesoporous Magnesium Carbonate. ACS Omega, 1(5), 907-914
Open this publication in new window or tab >>Investigation of the Antibacterial Effect of Mesoporous Magnesium Carbonate
2016 (English)In: ACS Omega, ISSN 2470-1343, Vol. 1, no 5, p. 907-914Article in journal (Refereed) Published
Abstract [en]

Mesoporous magnesium carbonate (MMC) was first presented in 2013, and this material is currently under consideration for use in a number of biotechnological applications including topical formulations. This study presents the first evaluation of the antibacterial properties of the material with mesoporous silica and two other magnesium-containing powder materials used as references. All powder materials in this study are sieved to achieve a particle size distribution between 25 and 75 μm. The Gram-positive bacterium Staphylococcus epidermidis is used as the model bacterium due to its prevalence on human skin, its likelihood of developing resistance to antibiotics, for example, from routine exposure to antibiotics secreted in sweat, and because it is found inside affected acne vulgaris pores. Quantification of bacterial viability using a metabolic activity assay with resazurin as the fluorescent indicator shows that MMC exerts a strong antibacterial effect on the bacteria and that alkalinity accounts for the major part of this effect. The results open up for further development of MMC in on-skin applications where bacterial growth inhibition without using antibiotics is deemed favorable.

National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-307385 (URN)10.1021/acsomega.6b00124 (DOI)000392719300020 ()
Funder
Swedish Research Council
Available from: 2016-11-14 Created: 2016-11-14 Last updated: 2017-03-02Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4543-1130

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