| 1. |
- Stenius, P, et al.
(författare)
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Nonionic hydrophilic surfaces: adsorption and interactions
- 1990
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Ingår i: Croatica Chemica Acta. - 0011-1643 .- 1334-417X. ; 63, s. 501-516
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Tidskriftsartikel (refereegranskat)abstract
- An overview is given of recent studies of nonionic, hydrophilic surfaces formed by the adsorption surfactants or surface active polymers. Hydrophobic surfaces can be easily hydrophilized by the adsorption of nonionic surfactants or block copolymers containing hydrophobic chain segements; the cooperative interaction between the hydrocarbon moieties contributes more to the free energy of adsorption than the interaction with the hydrophobic surface. Hydrophilic layers are also readily formed on hydrophilic surfaces provided specific interaction between the hydrophilic end groups and the surface creates a sufficiently hydrophobic surface so that a second layer can bed formed through cooperative interaction. The temperature dependence of the interaction forces between layers of surfactants can be closely correlated with their phase equilibria with water. In order to prevent protein adsorption the surface should be neither charged nor hydrophobic; it is shown that, accordingly, protein adsorption is extremely low on poly ethylene oxide-covered surfaces.
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| 2. |
- Blomberg, E, et al.
(författare)
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Adhesion of trimyristin fat to radio frequency plasma treated PVC and chromium
- 1990
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Ingår i: Langmuir. - 0743-7463 .- 1520-5827. ; 6, s. 1499-1504
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Tidskriftsartikel (refereegranskat)abstract
- There is an increasing belief in the use of surface modification techniques to reduce the adhesion of soil to surface so that only weak detergents or mechanical means is required for the soil removal. In this work, we have studied how the soil adhesion is affected by controlled and well-defined modification of thr surface. Various surfaces were prepared by radio frequency plasma treatment combined with surface derivatization techninques. Adsorption and displacement of trimyristin , a model soil, were investigated by ellipsometry. Two fundametally different and succesful approaches to realize a good soil-repellant surface werw found:(i) strongly polar surfaces of poly(ethylene oxide) that interact strongly with water or (ii) surfaces which contain cross-linked fluorocarbon moieties.
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| 3. |
- Cho, DL, et al.
(författare)
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Structure and surface properties of plasma polymerized acrylic acid layers
- 1990
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Ingår i: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 41, s. 1373-1390
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Tidskriftsartikel (refereegranskat)abstract
- Thin plasma polymerized layers of acrylic acid (PPAA) were deposited onto polyethylene and muscovite mica surfaces. Structure and surface properties of the deposited layer depend on the polymerization conditions. The content of carboxylic groups in the layer decreases, whereas the degree of crosslinking or branching increases, with increasing discharge power. A soft, sticky layer with a low contact angle against water is obtained when a low discharge power (5 W) is used. In contrast, a hard film with a rather high water contact angle is obtained when the discharge power is high (50 W). A surface force apparatus was employed to study some film properties including adhesion force, crack formation, and capillary condensation. The adhesion force between plasma polymerized acrylic acid layers prepared at a low discharge power is high in dry air. It decreases remarkably in humid air and no adhesion is observed in water. In dry air, the adhesion force between PPAA layers decreases as the discharge power increases.
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| 4. |
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| 5. |
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| 6. |
- Elwing, H, et al.
(författare)
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Protein and detergent interaction phenomena on solid surfaces with gradients in chemical composition
- 1990
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Ingår i: Advances in Colloid and Interface Science. - 0001-8686 .- 1873-3727. ; 32, s. 317-339
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Tidskriftsartikel (refereegranskat)abstract
- We have recently described a new method for analysis of protein interaction on solid surfaces. The basic idea of the method is to make a gradient of chemical groups on the surface and to quantify protein adsorption along the gradient with the use of optical methods such as fluorescence measurements or ellipsometry. We have used the technique for experiments on protein adsorption and exchange, and detergent interaction on wettability gradients made on, e.g., silicon oxide surfaces. Several new observations were made which can not be observed without the use of the gradient method. This contribution is a short review of these obtaineer results and related research problems.
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| 7. |
- Gölander, C-G, et al.
(författare)
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Absorption of human lysozyme and adsorbate enzyme activity as quantified by means of total internal reflection fluorescence, 125I labelling and ESCA
- 1990
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Ingår i: Colloids and Surfaces. - 0166-6622 .- 1873-4340. ; 50, s. 113-130
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption of human lyozyme to bare mica and mica hydrophobised with a C20NH2/C20OH Langmuir-Blodgett film was quantified by means of ESCA, radiotracer technique and total internal retlection fluorescence (TIRF). The ESCA isotherm on bare mica showed a sigmoidal shape with a transition region in the concentration range 0.02-0.04 mg ml -1 and a semiplateau region above 0.05-0.2 mg ml -1. The adsorption values here rougly corresponded to a side-up monolayer, 2.2-2.5 mg m-2. In contrast, on hydrophobised mica, a gradual increase in adsorption was obseved over the whole concentration range studied, 10-3-10 mg ml-1. The adsorbed amount in equilibrium with a 1 mg ml -1 slution was 1.4 mg m -2. At concentrations above phobised mica surface. These results are consistent with a strong electrostatic force dominationg the adsorption on bare mica and a weak hydrophobic driving force for adsorption on hydrophoised mica. Although the isotherm shapes were similar, the absolute adsorption values obtained from TIRF and radioactive measurements were considerably different from those obtained from ESCA. The lower apparent adsorption values, can be rationalized by a change in fluorescein-labelled lysozyme, e.g., roughly half of the ESCA values, can be rationalized by a change in fluorescence quantum yield of the fluors on adsorption or possibly by preferential adsorption of unlabelled lysozyme. The apparent two to three times higher adsorption values obtained from 125 I labelling measurements can be explained by an apparent sample area which is lager than the geometric area due to adsorption of labelled lysozyme in the interstices between mica layers. The normalized adsorption of fluorescein labelled polyclonal anti-lysozyme antibodies was similar on bare and hydrophilised mica. around 0.9 mole/mole for a surface equilibrated in a lysozyme solution at 0.02 mg ml -1. and 0.3 mole/mole at 2.0 mg ml -1(size exclusion). The steady state binding and steady state enzymatic cleavage of a fluorogenic lysozyme substrate, 4-methylumbelliferyl N,N,N-triacetyl-B-chitotrioside, on the lysozyme adsorbate layers.
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| 8. |
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Gölander, C-G, et al.
(författare)
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Structure and surface properties of diaminocyclohexane plasma polymer films
- 1993
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Ingår i: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 49, s. 39-51
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Tidskriftsartikel (refereegranskat)abstract
- Plasma polymers of three isomers of diaminocyclohexane (DACH) were deposited on polyethylene, SiO2, and mica at 20 °C. The deposition rate was measured as a function of plasma density and power; a maximum was observed in the latter function. The deposition rate was highest for the monomer with the highest flow rate. The film refractive index was observed to increase with both power density and the degree of fragmentation in the plasma. Film composition was measured by elementary analysis, and was found to be almost identical for each of the three isomers; a mechanism for the polymerization reaction is proposed. The percentage of primary amino groups decreased with increasing power density and with film thickness. Surface force measurements of the thickness and refractive index agreed well with the corresponding ellipsometry values in dry air, and an adhesive force, independent of power density, was measured. When the film was exposed to water vapor, it swelled considerably and the adhesion was determined by capillary forces. Associated with swelling, at high power, was an extremely regular 2-ply rope pattern of protruding material.
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Kiss, E, et al.
(författare)
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Chemical derivatization of muscovite mica surfaces
- 1990
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Ingår i: Colloids and Surfaces. - 0166-6622 .- 1873-4340. ; 49, s. 335-342
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Tidskriftsartikel (refereegranskat)abstract
- A method to modify mica chemically by means of a plasma discharge in water vapour, to form reactive silanol groups, followed by silyation with isocyanatopropyldimethylchlorosilane has been developed. The introduction of isocyanatopropyl moieties on the surface enables the performance of a wide range of organic derivatization reactions. As examples, amino- and ethylene oxide-functional surfaces have been prepared. The surface film compositions have been quantitatively studied by ESCA. The interaction force in water between poly (ethylene oxide) layers covalently attached to mica, as measured in a surface force apparatus, was repulsive at separations less than 20-30 nm.
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| 17. |
- Kiss, E, et al.
(författare)
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Static and dynamic wetting behaviour of poly(ethylene oxide) layer formed on mica substrate
- 1991
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Ingår i: Colloids and Surfaces. - 0166-6622 .- 1873-4340. ; 58, s. 263-270
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Tidskriftsartikel (refereegranskat)abstract
- Dynamic wetting of poly(ethylene oxide)-, PEO; grafted mica surface has been investigated by a tensiometric method based on the Wilhelmy balance. Advancing and receding contact angles were determined under static conditions as well as at different contact line velocities in the range 0.1-5.0 mm s-1. The wetting medium and conditions were chosen according to the phase behaviour of PEO determined in solution. Wetting parameters characterizing the surface/liquid interaction measured on a system below and above the theta conditions differ considerably. Contact angles of water or aqueous electrolyte solution were found to be increased while heterogeneity of the surface was reduced with increasing temperature and salt concentration stressing the role of chain mobility in the special properties of PEO surface. Dynamic wetting of poly(ethylene oxide)-, PEO; grafted mica surface has been investigated by a tensiometric method based on the Wilhelmy balance. Advancing and receding contact angles were determined under static conditions as well as at different contact line velocities in the range 0.1-5.0 mm s-1. The wetting medium and conditions were chosen according to the phase behaviour of PEO determined in solution. Wetting parameters characterizing the surface/liquid interaction measured on a system below and above the theta conditions differ considerably. Contact angles of water or aqueous electrolyte solution were found to be increased while heterogeneity of the surface was reduced with increasing temperature and salt concentration stressing the role of chain mobility in the special properties of PEO surface.
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| 18. |
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| 19. |
- Malmsten, M, et al.
(författare)
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Adsorption of complement protein C3 at polymer surfaces
- 1996
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Ingår i: Journal of Colloid and Interface Science. - 0021-9797 .- 1095-7103. ; 179, s. 163-172
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption of C3 at poly(methyl methacrylate) (PMMA) and poly(styrene) (PS) surfaces was investigated with in situ ellipsometry and compared to that at (hydrophilic and negatively charged) silica and (hydrophobic) methylated silica. The adsorption of C3 at PMMA was higher than that at PS, while the adsorbed layer thickness was the same for the two surfaces. For both PMMA and PS the adsorbed layer thickness (10±2 nm) corresponds rather closely to that of end-on oriented C3 molecules. The adsorption of C3 at PMMA and PS was found to be intermediate between that at silica and methylated silica, although the adsorbed layer thickness was similar for all surfaces. The competitive adsorption between C3, human serum albumin (HSA), and factor B was investigated with ellipsometry and total internal reflection fluorescence spectroscopy (TIRF). Addition of HSA after C3 preadsorption resulted in fractional C3 desorption for both PMMA and PS. Factor B deposition at PS after preadsorption of C3 and blocking with HSA was found to be largely due to specific binding to C3/C3b, while in the case of PMMA, factor B was largely accumulated through passive (displacement) adsorption.
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| 20. |
- Malmsten, Martin, et al.
(författare)
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Adsorption of complement protein C3 at polymer surfaces and the demonstration of a specific binding of factor B by adsorbed C3
- 1996
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 179:1, s. 163-172
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption of C3 at poly(methyl methacrylate) (PMMA) and poly(styrene) (PS) surfaces was investigated within situellipsometry and compared to that at (hydrophilic and negatively charged) silica and (hydrophobic) methylated silica. The adsorption of C3 at PMMA was higher than that at PS, while the adsorbed layer thickness was the same for the two surfaces. For both PMMA and PS the adsorbed layer thickness (10 ± 2 nm) corresponds rather closely to that of end-on oriented C3 molecules. The adsorption of C3 at PMMA and PS was found to be intermediate between that at silica and methylated silica, although the adsorbed layer thickness was similar for all surfaces. The competitive adsorption among C3, human serum albumin (HSA), and factor B was investigated with ellipsometry and total internal reflection fluorescence spectroscopy (TIRF). Addition of HSA after C3 preadsorption resulted in fractional C3 desorption for both PMMA and PS. Factor B deposition at PS after preadsorption of C3 and blocking with HSA was found to be largely due to specific binding to C3/C3b, while in the case of PMMA, factor B was largely accumulated through passive (displacement) adsorption.
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| 21. |
- Tammela, T L, et al.
(författare)
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An Intraprostatic Modified Release Formulation of Antiandrogen 2-Hydroxyflutamide for Localized Prostate Cancer
- 2017
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Ingår i: Journal of Urology. - : Ovid Technologies (Wolters Kluwer Health). - 0022-5347 .- 1527-3792. ; 198:6, s. 1333-1339
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate tolerability, safety and antitumor effects of a novel intra-prostatic depot formulation of antiandrogen 2-hydroxyflutamide (2-HOF in NanoZolid(®)) in men with localized prostate cancer (PCa).MATERIALS AND METHODS: Two clinical trials, LPC-002 and LPC-003, were conducted on a total of 47 men. The formulation was injected transrectally into the prostate with ultrasound guidance. In LPC-002 the effects on prostate specific antigen (PSA) and prostate volume (PV) were measured over 6 months on 24 patients. In LPC-003, antitumor effects were evaluated with histopathology, magnetic resonance imaging (MRI) including spectroscopy (MRS) during 6 or 8 weeks on 23 patients. In both studies, testosterone and 2-HOF in plasma were measured, as well as quality-of-life parameters.RESULTS: In LPC-002 (mean dose 690 mg) a reduction in PSA and PV was observed. The nadir values for PSA and PV were on average 24.9 % and 14.0 % below baseline, respectively. When increasing the dose in LPC-003 (920 mg and 1740 mg), the average PSA dropped 16 % and 23 %, respectively, after 6 and 8 weeks. MRI/MRS showed morphological changes and a global drop in metabolite concentrations following treatment indicating an antitumor response. The injections did not result in hormone related side effects. In total, three serious adverse events were reported, all resolved by oral antibiotic treatment.CONCLUSIONS: The intraprostatic injections of 2-HOF depot formulations indicated anti-tumor effects and proved safe and tolerable. However, for better anti-cancer effects higher doses and better dose distribution are suggested.
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