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Browsing Faculty of Health and Society by Title
Now showing items 1-20 of 1291
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25 years of factorial surveys in sociology: A review Wallander, Lisa
Journal article in Social Science Research;3 : ELSEVIER (2009)peer-reviewed 
scientific
ARTICLE
English abstract: The aim of the factorial survey approach is to uncover the social and individual structures of human judgements of social objects. By having respondents evaluate samples of vignettes (fictive descriptions), in which several factors describing the object of interest are simultaneously manipulated, this approach has a number of advantages over traditional social survey research. The aim of the present article is to provide an easy-to-follow overview of the various ways in which the approach has been applied within sociology between 1982 and 2006. The review, which is based on 106 articles published in central sociology journals, is organised into three different sections: ‘‘factorial survey applications”, ‘‘factorial survey designs” and ‘‘factorial survey analyses”. -
Accountability and psychiatric disorders: how do forensic psychiatric... Höglund, Pontus; Levander, Sten; Anckarsäter, Henrik; Radovic, Susanna
Journal article in International journal of law and psychiatry;6 : Elsevier (2009)peer-reviewed
scientific
ARTICLE
English abstract: Swedish penal law does not exculpate on the grounds of diminished accountability; persons judged to suffer from severe mental disorder are sentenced to forensic psychiatric care instead of prison. Re-introduction of accountability as a condition for legal responsibility has been advocated, not least by forensic psychiatric professionals. To investigate how professionals in forensic psychiatry would assess degree of accountability based on psychiatric diagnoses and case vignettes, 30 psychiatrists, 30 psychologists, 45 nurses, and 45 ward attendants from five forensic psychiatric clinics were interviewed. They were asked (i) to judge to which degree (on a dimensional scale from 1 to 5) each of 12 psychiatric diagnoses might affect accountability, (ii) to assess accountability from five case vignettes, and (iii) to list further factors they regarded as relevant for their assessment of accountability. All informants accepted to provide a dimensional assessment of accountability on this basis and consistently found most types of mental disorders to reduce accountability, especially psychotic disorders and dementia. Other factors thought to be relevant were substance abuse, social network, personality traits, social stress, and level of education. -
Activator protein-1 in carotid plaques is related to cerebrovascular... Goncalves, Isabel; Stollenwerk, Maria M; Lindholm, Marie W; Dias, Nuno; Pedro, Luis M; Fernandes e Fernandes, José; Moses, Jonatan; Nordin Fredrikson, Gunilla; Nilsson, Jan; Ares, Mikko PS
Journal article in Cardiovascular Pathology;1 : Elsevier (2011)peer-reviewed
scientific
ARTICLE
English abstract: Transcription factor activator protein-1 regulates genes involved in inflammation and repair. The aim of this study was to determine whether transcription factor activator protein-1 activity in carotid plaques is related to symptoms, lipid accumulation, or extracellular matrix composition. Methods: Twenty-eight atherosclerotic carotid plaques were removed by endarterectomy and divided into two groups based on the presence or absence of ipsilateral symptoms (b1 month ago). Activator protein-1 DNA binding activity was assessed, and subunit (c-Jun, JunD, JunB, c-Fos, FosB, Fra-1, Fra-2) protein levels analyzed by immunoblotting. Distribution of c-Jun in plaques was analyzed by immunohistochemistry. Results: Plaques associated with symptoms had increased activator protein-1 activity and increased expression of c-Jun and JunD, as compared to asymptomatic plaques. Fra-1 and Fra-2 were present in equal amounts in both groups, whereas JunB, FosB, and c-Fos were undetectable. Activator protein-1 activity correlated with cholesteryl ester and elastin in plaques and decreased with age. Activator protein-1 activity did not correlate with collagen, calcified tissue, or proteoglycan content. Conclusions: Activator protein-1 is increased in plaques associated with symptoms. The correlation between activator protein-1 and cholesteryl esters suggests that high activator protein-1 is a marker of plaque vulnerability. Activator protein-1 expression can also reflect the activation of repair processes. -
Active site-inactivated factor VIIa inhibits nuclear factor kappa B a... Stollenwerk, Maria Magdalena; Lasson, Åke; Andersson, Roland
Journal article in Journal of Surgical Research;2 : Elsevier (2012)peer-reviewed
scientific
ARTICLE
English abstract: BACKGROUND: Intestinal ischemia and reperfusion (I/R) injury is a pivotal mechanism in critical illness and in the development of multiple organ dysfunction syndrome, in which the nuclear factor kappa B (NF-κB) activation plays a central role. Intestinal I/R injury initiates the extrinsic tissue factor or factor VIIa-dependent pathway of coagulation, also of importance in multiple organ dysfunction syndrome. Our aim was to analyze NF-κB activation in I/R injury in the rat intestine and in two main "shock" organs, that is, the liver and lungs. Pretreatment with active site-inactivated factor VII (FVIIai), an inhibitor of the extrinsic pathway, was evaluated. -
Activity based assessment (BIA) – inter-rater reliability and staff e... Kjellin, Lars; Cizinsky Sjödahl, Rosmarie; Eklund, Mona
Journal article in Scandinavian Journal of Occupational Therapy (2008)peer-reviewed
scientific
ARTICLE -
Activity of lactoperoxidase when adsorbed on protein layers 
Haberska, Karolina; Svensson, Olof; Shleev, Sergey; Lindh, Liselott; Arnebrant, Thomas; Ruzgas, Tautgirdas
Journal article in Talanta;5 : Elsevier B.V. (2008)peer-reviewed
scientific
ARTICLE
English abstract: Lactoperoxidase (LPO) is an enzyme, which is used as an antimicrobial agent in a number of applications, e.g., food technology. In the majority of applications LPO is added to a homogeneous product phase or immobilised on product surface. In the latter case, however, the measurements of LPO activity are seldom reported. In this paper we have assessed LPO enzymatic activity on bare and protein modified gold surfaces by means of electrochemistry. It was found that LPO rapidly adsorbs to bare gold surfaces resulting in an amount of LPO adsorbed of 2.9 mg/m2. A lower amount of adsorbed LPO is obtained if the gold surface is exposed to bovine serum albumin, bovine or human mucin prior to LPO adsorption. The enzymatic activity of the adsorbed enzyme is in general preserved at the experimental conditions and varies only moderately when comparing bare gold and gold surface pretreated with the selected proteins. The measurement of LPO specific activity, however, indicate that it is about 1.5 times higher if LPO is adsorbed on gold surfaces containing a small amount of preadsorbed mucin in comparison to the LPO directly adsorbed on bare gold. 
Haberska08.pdf
(673.1Kb)
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Adaptation to Swedish and further development of the “Consequences of... Bolejko, Anetta; Wann-Hansson, Christine; Zackrisson, Sophia; Brodersen, John; Hagell, Peter
Journal article in Scandinavian Journal of Caring Sciences; : Wiley-Blackwell (2012)peer-reviewed
scientific
ARTICLE
English abstract: Abstract Scand J Caring Sci; 2012 Adaptation to Swedish and further development of the 'Consequences of Screening - Breast Cancer' questionnaire: a multimethod study Rationale: Experiencing a false-positive screening mammography can cause considerable psychosocial distress. The Consequences of Screening - Breast Cancer questionnaire (COS-BC parts 1 and 2), recently developed in Denmark, is the only condition-specific questionnaire for measuring short- and long-term psychosocial consequences of false-positive mammographic screening. Additional studies are needed to further test the COS-BC before use across cultures. Furthermore, studies have suggested that the consequences of false-positive screening results are partly common across cancer screening settings, although this hypothesis remains largely untested. Objectives: This study (i) assesses content validity of a Swedish version of the COS-BC, (ii) tests whether items expressing long-term consequences of false-positive lung cancer screening results are relevant in a breast cancer screening context and (iii) explores the usefulness of taking results from Rasch analyses of the source version as an aid in questionnaire translation and adaptation. Methods: Following dual-panel translation, content validity was assessed through qualitative interviews with representatives of the target population and the content validity index (CVI). Item locations and Rasch model fit of the source questionnaires were considered in the translation and assessment process. Results: The COS-BC items were generally found relevant and provided coverage of the target construct. Content validity was supported also for nine of 10 lung cancer screening items. Scale CVI values were ≥0.81. Previous Rasch data were useful in facilitating translation and assessing item content validity. The resulting Swedish version of the COS-BC parts 1 and 2 consists of 34 and 23 items, respectively. Conclusion: This study illustrates the value of methodological triangulation and use of data from previous Rasch analyses in questionnaire translation and adaptation. We found support for the hypothesis that consequences of false-positive screening are common across cancer screening settings. Psychometric properties of the Swedish COS-BC remain to be established -
Adapting the Individualised Care Scale for cross-cultural comparison:... Suhonen, Riitta; Berg, Agneta; Idvall, Ewa; Kalafati, Maria; Katajisto, Jouko; Land, Lucy; Lemonidou, Chryssoula; Schmimdt, Lee; Välimäki, Maritta; Leino-Kilpi, Helena
Journal article in Scandinavian Journal of Caring Sciences;2 (2010)peer-reviewed
scientific
ARTICLE
English abstract: Rationale: Cross-cultural comparative studies using reliable and valid instruments can increase awareness of the differences and similarities between health worker's ability to respond to patients' individual needs within different health systems. This will enable a better understanding of cultural perspectives in individualized nursing care. Aim: To describe the translation and adaptation process of the Individualized Care Scale (ICS) and examine its reliability and validity in a cross-cultural study. Design: A cross-sectional comparative study. Settings: Twenty-seven orthopaedic and trauma in-patient units at 14 hospitals in 5 countries. Participants: A total of 1126 patients were included in the study: Finland (n = 425), Greece (n = 315), Sweden (n = 218), UK (n = 135) and USA (n = 33). Methods: A systematic forward- and back-translation procedure using bilingual techniques, a committee approach, pretest techniques and pilot testing were used with a convenience sample to produce a valid ICS for each participating group. Psychometric evaluation of the adapted ICS was based on means, SD, missing data analysis, Cronbach's alpha coefficients and average inter-item correlations. Construct validity was examined using sub-scale correlations to total scales and principal components analysis. Results: The use of the range of options and the sub-scale mean scores ranging from 2.72 to 4.30 demonstrated the sensitivity of the scale. Cronbach's alpha coefficients (0.77-0.97) and average inter-item correlations (0.37-0.77) were acceptable. The sub-scale correlations to total scales were high (0.83-0.97). The underlying theoretical construct of the ICS was demonstrated by the explained variances ranging from 58% to 79%. Conclusions: The ICS shows promise as a tool for evaluating individualized care in European cultures. The international expansion of an existing instrument developed for one country facilitates comparative studies across countries. There is a need to further test the construct validity and appropriateness of the ICS in different settings in European and nonwestern cultures. -
Adolescent lifestyle risk by gender and ethnic background: Findings f... Pauwels, Lieven; Svensson, Robert
Journal article in European Journal of Criminology;1 : Sage Publications (2009)peer-reviewed
scientific
ARTICLE
English abstract: The aim of this paper is to explain individual differences in lifestyle risk. Lifestyle risk has previously been identified as a key social mechanism which has strong direct effects on juvenile offending. Building on statements derived from the Situational Action Theory (SAT), we test the assumptions that (1) family structure explains individual differences in lifestyle risk, (2) these effects are moderated by mechanisms of social control, and (3) the effects of mechanisms of control are moderated by the effect of propensity to offend (morality and self-control). It is assumed that this model holds in different population segments such as subpopulations by gender and ethnic background. Results from two independently drawn urban samples in Belgium and Sweden are used to discuss the generalization of these findings. Mixed support is found for the `equality of effects' thesis -
Adolescent mental health and utilisation of psychiatric care : the ro...
Ivert, Anna-Karin : Malmö University, Faculty of Health and Society
Malmö University Health and Society Doctoral Dissertations;1 (2013)DOCTORAL
THESIS
English abstract: The studies included in this thesis aim to illustrate different aspects of mental health and the utilisation of psychiatric care among Swedish children and adolescents, with the overarching aim being to improve the existing knowledge on how the neighbourhood of residence and parental country of birth influence adolescents’ mental health and their pathways into and utilisation of psychiatric care. The first study investigates referral pathways to child and adolescent psychiatric clinics, directing a special focus at how these pathways differ on the basis of parental country of birth and neighbourhood of residence. The results show that parental country of birth plays an important role in how children and adolescents are referred to the child and adolescent psychiatric sector. Children and adolescents with Swedish-born parents appear more often to have been referred by their families, whereas by comparison with children and adolescents with Swedish-born parents, those with foreign-born parents had more often than been referred by someone outside the family, such as the social services or their school. Neighbourhood of residence was found to play a significant role in relation to family referrals; children and adolescents living in neighbourhoods with low levels of socioeconomic deprivation were more likely to have been referred by their families by comparison with those from more deprived neighbourhoods. The second study investigates how parental country of birth and individual gender are associated with the utilisation of psychiatric care. The findings from the study indicate that adolescents whose parents were born in middleor low-income countries present lower levels of psychiatric outpatient care utilisation than those with Swedish-born parents. Initially, no associations 7 were found between parental country of birth and inpatient care. Following adjustment for socio-demographic variables, it was found that adolescents whose parents were born in low-income countries were also less likely to utilise inpatient care. Girls were more likely to have utilised psychiatric care, but controlling for possible interactions revealed that this was true primarily for girls with parents born in Sweden or other high-income countries. In the third study, psychiatric care utilisation patterns are analysed in relation to the neighbourhood of residence. In part the aim was to investigate the validity of the neighbourhood when it comes to understanding variations in adolescents’ utilisation of psychiatric care, but the study also examines whether neighbourhood socioeconomic deprivation is associated with individual variations in the utilisation of psychiatric care. The results indicate that the neighbourhood of residence has little influence on the utilisation of psychiatric care, only 1.6 % of the variance was found at the neighbourhood level. No clear association between the neighbourhood level of socioeconomic deprivation and levels of psychiatric care utilisation was found in the study. The final study investigates how adolescents’ perceptions of the social characteristics of their neighbourhood are related to their self-reported mental health, while controlling for the socioeconomic structure of the neighbourhood. The results show that adolescents’ perceptions of their neighbourhood are associated with their self-reported mental health, particularly their perceptions of social disorder. However, these associations differ between girls and boys, and between adolescents with Swedish- and foreign-born parents. In conclusion, the results presented in the thesis show that parental country of birth is an important factor when it comes to understanding differences in referral patterns and in the utilisation of psychiatric care. However, the role of the neighbourhood of residence appears to be more complex.
15177 Ivert muep_ny(kappan).pdf
(670.0Kb)
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Adsorption behaviour and surfactant elution of cationic salivary prot...
Svendsen, Ida; Lindh, Liselott; Arnebrant, Thomas
Journal article in Colloids and Surfaces B: Biointerfaces;2 : Elsevier (2006)peer-reviewed
scientific
ARTICLE
English abstract: Adsorption of the cationic salivary proteins lactoferrin, lactoperoxidase, lysozyme and histatin 5 to pure (hydrophilic) and methylated (hydrophobized) silica surfaces was investigated by in situ ellipsometry. Effects of concentration (≤10 μg ml−1, for lysozyme ≤200 μg ml−1) and dependence of surface wettability, as well as adsorption kinetics and elutability of adsorbed films by buffer and sodium dodecyl sulphate (SDS) solutions were investigated. Results showed that the amounts adsorbed decreased in the order lactoferrin ≥ lactoperoxidase > lysozyme ≥ histatin 5. On hydrophilic silica, the adsorption was most likely driven by electrostatic interactions, which resulted in adsorbed amounts of lactoferrin that indicated the formation of a monolayer with both side-on and end-on adsorbed molecules. For lactoperoxidase the adsorbed amounts were somewhat higher than an end-on monolayer, lysozyme adsorption showed amounts corresponding to a side-on monolayer, and histatin 5 displayed adsorbed amounts in the range of a side-on monolayer. On hydrophobized substrata, the adsorption was also mediated by hydrophobic interactions, which resulted in lower adsorbed amounts of lactoferrin and lactoperoxidase; closer to side-on monolayer coverage. For both lysozyme and histatin 5 the adsorbed amounts were the same as on the hydrophilic silica. The investigated proteins exhibited fast adsorption kinetics, and the initial kinetics indicated mass transport controlled behaviour at low concentrations on both types of substrates. Buffer rinsing and SDS elution indicated that the proteins in general were more tightly bound to the hydrophobized surface compared to hydrophilic silica. Overall, the surface activity of the investigated proteins implicates their importance in the salivary film formation.
sdarticle.pdf
(461.2Kb)
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Adsorption behaviour of statherin and a statherin peptide onto hydrox... Santos, Olga; Liselott, Lindh; Kosoric, Jelena; Hector, Mark; Anderson, Paul
Journal article in Journal of Interface and Colloid Science 2 : Elsevier (2007)peer-reviewed
scientific
ARTICLE
English abstract: The salivary protein statherin is known to adsorb selectively onto hydroxyapatite (HA), which constitutes the main mineral of the tooth enamel. This adsorption is believed to be crucial for its function as an inhibitor of primary (spontaneous) and secondary (crystal growth) precipitation of calcium phosphate salts present in saliva. A fragment corresponding to the first 21 N-terminus amino acids of statherin (StN21) was previously found to reduce the rate of demineralisation of HA. Therefore, the interfacial properties of this peptide and statherin onto silica, hydrophobized silica and HA discs was studied by in situ ellipsometry. Their reversibility induced by dilution and elutability induced by buffer and sodium dodecyl sulphate (SDS) was also determined. The results revealed that statherin adsorbed at a greater extent onto the HA as compared to StN21, suggesting that the hydrogen bonding between the uncharged polar residues at the C-terminal region of statherin and HA contributes to its adsorption. However, on both silica surfaces the peptide adsorption appeared to proceed in a similar way. Onto the hydrophobized silica the adsorption of both peptides was suggested to occur either via multilayer formation or adsorption of aggregates from solution, while onto the hydrophilic silica adsorption of peptide aggregates from solution was the suggested mechanism. Further, both peptides were observed to be strongly adsorbed onto HA, even after SDS treatment, in comparison to the layers adsorbed onto hydrophobized silica. Both peptide layers were found to be weakly adsorbed onto the hydrophilic silica surface as they were totally removed by buffer dilution. -
Adsorption behaviour of statherin and a statherin peptide onto hydrox... Santos, Olga; Kosoric, Jelena; Hector, Mark P; Anderson, Paul; Lindh, Liselott
Journal article in Journal of colloid and interface science;2 (2008)peer-reviewed
scientific
ARTICLE
English abstract: The salivary protein statherin is known to adsorb selectively onto hydroxyapatite (HA), which constitutes the main mineral of the tooth enamel. This adsorption is believed to be crucial for its function as an inhibitor of primary (spontaneous) and secondary (crystal growth) precipitation of calcium phosphate salts present in saliva. A fragment corresponding to the first 21 N-terminus amino acids of statherin (StN21) was previously found to reduce the rate of demineralization of HA. Therefore, the interfacial properties of this peptide and statherin onto silica, hydrophobized silica and HA discs was studied by in situ ellipsometry. Their reversibility induced by dilution and elutability induced by buffer and sodium dodecyl sulfate (SDS) was also determined. The results revealed that statherin adsorbed at a greater extent onto the HA as compared to StN21, suggesting that the hydrogen bonding between the uncharged polar residues at the C-terminal region of statherin and HA contributes to its adsorption. However, on both silica surfaces the peptide adsorption appeared to proceed in a similar way. Onto the hydrophobized silica the adsorption of both peptides was suggested to occur either via multilayer formation or adsorption of aggregates from solution, while onto the hydrophilic silica adsorption of peptide aggregates from solution was the suggested mechanism. Further, both peptides were observed to be strongly adsorbed onto HA, even after SDS treatment, in comparison to the layers adsorbed onto hydrophobized silica. Both peptide layers were found to be weakly adsorbed onto the hydrophilic silica surface as they were totally removed by buffer dilution. -
Adsorption from Black Tea and Red Wine onto IN Vitro Salivary Pellicl... Joiner, Andrew; Arnebrant, Thomas; Malmsten, M; Elofsson, U.M.
Journal article in European journal of oral sciences;5 : Blackwell Publisher (2003)peer-reviewed
scientific
ARTICLE
English abstract: The adsorption of black tea and red wine components onto a pellicle-like protein layer formed in vitro by adsorption from whole unstimulated saliva on hydroxyapatite discs were studied by in situ ellipsometry. It was found that components from black tea readily adsorbed to the pellicle. Subsequent exposure to saliva led to further adsorption of salivary components to give an overall increase in the amounts adsorbed. The amounts adsorbed increased still further following a third tea and saliva exposure. Components of red wine gave significantly greater amounts of adsorption to the pellicle than black tea. The adsorption of components of black tea gave a concomitant increase in colour or stain as measured by a reflectance chromameter. In all cases, the black tea- and red wine-modified pellicles were not eluted by either phosphate buffer or sodium dodecyl sulphate (SDS) rinses. Thus, black tea and red wine components have been shown to have a profound effect on in vitro pellicle maturation, causing thickened layers of stained material to build up, which are not readily removed. -
Adsorption of chlorhexidine and black tea onto in vitro salivary pell... Arnebrant, Thomas; Joiner, Andrew; Elofsson, Ulla
Journal article in European Journal of Oral Sciences (2006)peer-reviewed
scientific
ARTICLE
English abstract: The adsorption from 0.2% (w/w) chlorhexidine and black tea solutions onto an in vitro pellicle from whole unstimulated saliva on hydroxyapatite discs was studied by ellipsometry. It was found that chlorhexidine adsorbed to the pellicle causing a modification of the pellicle properties, leading to a subsequent increase in adsorption of salivary and black tea components. There was a distinct order of addition effect, whereby chlorhexidine followed by black tea gave an overall greater adsorption of components compared to black tea followed by chlorhexidine. This increase in adsorption gave a concomitant increase in colour or stain as measured by a reflectance chromameter. The increase in adsorbed amounts and stain was modified in part by the adsorption of salivary fractions between the chlorhexidine and black tea treatments. In all cases, the chlorhexidine and black tea modified pellicles were not readily removed by either phosphate or sodium dodecyl sulphate rinses. Thus, following chlorhexidine exposure, the accelerated adsorption of salivary and black tea components can ultimately lead to increased staining of the pellicle. -
Adsorption of delmopinol at the solid/liquid interface - the role of ... Svensson, Olof; Halthur, Tobias; Sjödin, Torgny; Arnebrant, Thomas
Journal article in Journal of Colloid and Interface Science;1 : Elsevier Inc. (2010)peer-reviewed
scientific
ARTICLE
English abstract: Delmopinol is a tertiary amine surfactant that is used to counteract dental plaque formation. As it is of interest to understand the interfacial behavior from both fundamental and applied perspectives the adsorption of delmopinol to model surfaces was investigated. Adsorption on Teflon, titanium and stainless steel was studied by radioactive labeling and adsorption on silica was studied by quartz crystal microbalance (QCM), ellipsometry and particle electrophoresis. It was shown that the adsorption of delmopinol was complex and strongly influenced by pH and concentration. Pronounced peak values were detected in the adsorption curves (adsorbed amount versus concentration) exceeding the expected value for a bilayer type of structure. To account for this behavior two surface active component were assumed to be present. Accordingly, the high amounts result from the deposition of the component with lower solubility and the decrease at the critical micelle concentration can be explained by solubilization of this component. Based on data from several experimental methods and the pH dependence of the effect we propose an explanation in which the protonated and non-protonated forms of delmopinol represent the two components. However, it cannot be excluded that the component with the lower solubility could be a compound chemically different from delmopinol in the sample. -
Adsorption of HSA, IgG and laminin-1 on model hydroxyapatite surfaces...
Svendsen, Ida; Santos, Olga; Sotres, Javier; Wennerberg, Ann; Breding, Karin; Arnebrant, Thomas; Lindh, Liselott
Journal article in Biofouling : The Journal of Bioadhesion and Biofilm Research;1 : Taylor & Francis Group (2012)peer-reviewed
scientific
ARTICLE
English abstract: Ellipsometry and mechanically assisted sodium dodecyl sulphate elution was utilized to study the adsorption of human serum albumin (HSA), human immunoglobulin G (IgG), and laminin-1, as well as competitive adsorption from a mixture of these proteins on spin-coated and sintered hydroxyapatite (HA) surfaces, respectively. The HA surfaces were characterized with respect to wettability and roughness by means of water contact angles and atomic force microscopy, respectively. Both surface types were hydrophilic, and the average roughness (Sa) and surface enlargement (Sdr) were lower for the sintered compared to the spin-coated HA surfaces. The adsorbed amounts on the sintered HA increased as follows: HSA < laminin-1 < IgG < the protein mixture. For the competitive adsorption experiments, the adsorbed fractions increased accordingly: HSA < laminin-1 < IgG on both types of HA substratum. However, a higher relative amount of HSA and laminin-1 and a lower relative amount of IgG was found on the spin-coated surfaces compared to the sintered surfaces. The effects observed could be ascribed to differences in surface roughness and chemical composition between the two types of HA substratum, and could have an influence on selection of future implant surface coatings.
manuscript_Svendsen_et_al_111027.pdf
(1.496Mb)
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Adsorption of HSA, IgG and laminin-1 on model titania surfaces – effe... Santos, Olga; Svendsen, Ida E; Lindh, Liselott; Arnebrant, Thomas
Journal article in Biofouling;9 : Taylor & Francis (2011)peer-reviewed
scientific
ARTICLE
English abstract: This study investigated the effect of glow discharge treatment of titania surfaces on plasma protein adsorption, by means of ellipsometry and mechanically assisted SDS elution. The adsorption and film elution of three plasma proteins, viz. human serum albumin (HSA), human immunoglobulin G (IgG) and laminin-1, as well as competitive adsorption from a mixture of the three proteins, showed that the adsorbed amount of the individual proteins after 1 h increased in the order HSA <IgG <laminin-1 ≤ protein mixture. Film elutability showed that 30 min of SDS interaction resulted in almost complete removal of adsorbed films. No difference in the total adsorbed amounts of individual proteins, or from the mixture, was observed between untreated and glow discharge treated titania surfaces. However, the composition of the adsorbed films from the mixture differed between the untreated and glow discharge treated substrata. On glow discharge-treated titania the fraction of HSA increased, the fraction of laminin-1 decreased and the fraction of IgG was unchanged compared to the adsorption on the untreated titania, which was attributed to protein-protein interactions and competitive/associative adsorption behaviour. -
Adsorption of lipid liquid crystalline nanoparticles on cationic, hyd... Chang, Debby P.; Jankunec, Marija; Barauskas, Justas; Tiberg, Fredrik; Nylander, Tommy
Journal article in ACS Applied Materials and Interfaces;5 : American Chemical Society (2012)peer-reviewed
scientific
ARTICLE
English abstract: Investigation of nonlamellar nanoparticles formed by dispersion of self-assembled lipid liquid crystalline phases is stimulated by their many potential applications in science and technology; resulting from their unique solubilizing, encapsulating, and space-dividing nature. Understanding the interfacial behavior of lipid liquid crystalline nanoparticles (LCNPs) at surfaces can facilitate the exploitation of such systems for a number of potentially interesting uses, including preparation of functional surface coatings and uses as carriers of biologically active substances. We have studied the adsorption of LCNP, based on phosphatidylcholine/glycerol dioleate and Polysorbate 80 as stabilizers, at different model surfaces by use of in situ ellipsometry. The technique allows time-resolved monitoring of the layer thickness and the amount adsorbed, thereby providing insights into the restructuring of the lipid nanoparticle upon adsorption. The effects of solvent condition, electrolyte concentration, particle size, and surface chemistry on adsorbed layer properties were investigated. Furthermore, the internal structures of the particles were investigated by cryo-transmission electron microscopy and small angle X-ray diffraction on the corresponding liquid crystalline phases in excess water. LCNPs are shown to form well-defined layers at the solid–liquid interface with a structure and coverage that are determined by the interplay between the self-assembly properties of the lipids and lipid surface interactions, respectively. At the hydrophobic surface, hydrophobic interaction results in a structural transition from the original LCNP morphology to a monolayer structure at the interface. In contrast, at cationic and hydrophilic surfaces, relaxation is a relatively slow process, resulting in much thicker adsorbed layers, with thickness and adsorption behavior that to a greater extent reflect the original bulk LCNP properties. -
Adsorption of lipid liquid crystalline nanoparticles : effects of par... Chang, Debby P.; Jankunec, Marija; Barauskas, Justas; Tiberg, Fredrik; Nylander, Tommy
Journal article in Langmuir;29 : American Chemical Society (2012)peer-reviewed
scientific
ARTICLE
English abstract: Controlling the interfacial behavior and properties of lipid liquid crystalline nanoparticles (LCNPs) at surfaces is essential for their application for preparing functional surface coatings as well as understanding some aspects of their properties as drug delivery vehicles. Here we have studied a LCNP system formed by mixing soy phosphatidylcholine (SPC), forming liquid crystalline lamellar structures in excess water, and glycerol dioleate (GDO), forming reversed structures, dispersed into nanoparticle with the surfactant polysorbate 80 (P80) as stabilizer. LCNP particle properties were controlled by using different ratios of the lipid building blocks as well as different concentrations of the surfactant P80. The LCNP size, internal structure, morphology, and charge were characterized by dynamic light scattering (DLS), synchrotron small-ange X-ray scattering (SAXS), cryo-transmission electron microscopy (cryo-TEM), and zeta potential measurements, respectively. With increasing SPC to GDO ratio in the interval from 35:65 to 60:40, the bulk lipid phase structure goes from reversed cubic micellar phase with Fd3m space group to reversed hexagonal phase. Adding P80 results in a successive shift toward more disorganized lamellar type of structures. This is also seen from cryo-TEM images for the LCNPs, where higher P80 ratios results in more extended lamellar layers surrounding the inner, more dense, lipid-rich particle core with nonlamellar structure. When put in contact with a solid silica surface, the LCNPs adsorb to form multilayer structures with a surface excess and thickness values that increase strongly with the content of P80 and decreases with increasing SPC:GDO ratio. This is reflected in both the adsorption rate and steady-state values, indicating that the driving force for adsorption is largely governed by attractive interactions between poly(ethylene oxide) (PEO) units of the P80 stabilizer and the silica surface. On cationic surface, i.e., silica modified with 3-aminopropltriethoxysilane (APTES), the slightly negatively charged LCNPs give rise to a very significant adsorption, which is relatively independent of LCNP composition. Finally, the dynamic thickness measurements indicate that direct adsorption of intact particles occurred on the cationic surface, while a slow buildup of the layer thickness with time is seen for the weakly interacting systems.
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