| 1. |
- Ferreira, Guilherme A., et al.
(författare)
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Addition of n-Alcohols Induces a Variety of Liquid-Crystalline Structures in Surfactant-Rich Cores of Dispersed Block Copolymer/Surfactant Nanoparticles
- 2016
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 1:6, s. 1104-1113
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Tidskriftsartikel (refereegranskat)abstract
- Poly(acrylamide)-b-complex salts made from a symmetric poly(acrylate-b-acrylamide) block copolymer, where the acrylate charges are neutralized by cationic surfactant counterions, form kinetically stable aqueous dispersions of hierarchical aggregates with a liquid-crystalline complex salt core and a diffuse hydrated shell. By the addition of suitable amounts of long-chain alcohols, such as octanol or decanol, the structure of the internal phase can be varied, producing micellar cubic, hexagonal, lamellar, or reverse hexagonal liquid-crystalline phases. In addition, a disordered reverse micellar phase forms at the highest content of octanol. These core structures are the same as those previously obtained for macroscopic homopolymer poly(acrylate) complex salt/water/n-alcohol systems at the corresponding compositions. The poly(acrylamide)-b-complex salt dispersions are kinetically stable for several weeks, with their colloidal properties and internal structures remaining unchanged. The methodology described here establishes an easy and robust protocol for the preparation of colloidal nanoparticles with variable but controlled internal structures.
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| 2. |
- Mestres, Gemma, et al.
(författare)
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Evaluation of Biocompatibility and Release of Reactive Oxygen Species of Aluminum Oxide-Coated Materials
- 2016
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 1:4, s. 706-713
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Tidskriftsartikel (refereegranskat)abstract
- Surface properties of biomaterials can strongly influence biomaterial−host interactions. For this reason, coating processes open a wide range of possibilities to modulate the fate of a biomaterial in the body. This study evaluates the effect of a coating material intended for drug delivery capsules on biocompatibility and the release of reactive oxygen species (ROS), that is, respiratory burst in macrophages that indicates acute inflammation. In parallel with a new approach to develop drug-delivery capsules by directly coating solid-state drug particles, in this study, glass slides and silicon nanoparticles (NPs) were coated with aluminum oxide (Al2O3) using atomic layer deposition. Different sizes of NPs (20 and 310 nm) were suspended at different concentrations (10, 100, and 1000 μg/mL) and were evaluated. The homogeneous coating of slides was proved using X-ray photoelectron spectroscopy, and the coating on NP was observed using transmission electron microscopy. Human dermal fibroblasts and human osteoblasts were able to proliferate on the coated slides and in the presence of a suspension of coated NPs (20 and 310 nm) at a low concentration (10 μg/mL). The macrophages released ROS only when in contact with NPs at a concentration of 1000 μg/mL, where the 20 nm NPs caused a higher release of ROS than the 310 nm NPs. This study shows that Al2O3 coatings do not affect the cells negatively and that the cell viability was compromised only when in contact with a high concentration (1000 μg/mL) of smaller (20 nm) NPs.
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| 3. |
- Park, Jaehyeung, et al.
(författare)
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Three-Dimensional Graphene-TiO2 Nanocomposite Photocatalyst Synthesized by Covalent Attachment
- 2016
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 1:3, s. 351-356
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Tidskriftsartikel (refereegranskat)abstract
- We report the synthesis of a three-dimensional graphene (3DG)-TiO2 nanocomposite by covalently attaching P25 TiO2 nanoparticles onto pristine 3DG through a perfluorophenyl azide-mediated coupling reaction. The TiO2 nanoparticles were robustly attached on the 3DG surface, with minimal particle agglomeration. In photocatalytic CO2 reduction, the 3DG-TiO2 nanocomposite demonstrated excellent activity, about 11 times higher than that of the P25 TiO2 nanoparticles. The enhanced activity can be partially attributed to the highly dispersed state of the P25 TiO2 nanoparticles on the 3DG substrate. This 3DG-based system offers a new platform for fabricating photocatalytic materials with enhanced activities.
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| 4. |
- Welch, Kenneth, 1968-, et al.
(författare)
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Investigation of the Antibacterial Effect of Mesoporous Magnesium Carbonate
- 2016
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 1:5, s. 907-914
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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