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Östblom, Mattias
Publications (10 of 17) Show all publications
Bittoun, E., Marmur, A., Östblom, M., Ederth, T. & Liedberg, B. (2009). Filled Nanoporous Surfaces: Controlled Formation and Wettability. LANGMUIR, 25(20), 12374-12379
Open this publication in new window or tab >>Filled Nanoporous Surfaces: Controlled Formation and Wettability
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2009 (English)In: LANGMUIR, ISSN 0743-7463, Vol. 25, no 20, p. 12374-12379Article in journal (Refereed) Published
Abstract [en]

The controlled filling of hydrophobic nanoporous surfaces with hydrophilic molecules and their wetting properties are described and demonstrated by using thiocholesterol (TC) self-assembled monolayers (SAMs) on gold and mercaptoundecanoic acid (MUA) as the filling agent. A novel procedure was developed for filling the nanopores in the TC SAMs by immersing them into a "cocktail" solution of TC and MUA, with TC in huge excess. This procedure results in an increasing coverage of MUA with increasing immersion time up to an area fraction of similar to 23%, while the amount of TC remains almost constant. Our findings strongly support earlier observations where linear omega-substituted alkanethiols selectively fill defects (nanopores) in the TC SAM (Yang et al. Langmuir 1997, 12, 1704-1707). They also support the formation of a homogeneously mixed SAM, given by the distribution of TC on the gold surface, rather than of a phase-segregated overlayer structure with domains of varying size, shape, and composition. The wetting properties of the Filled SAMs were investigated by measuring the most stable contact angle as well as contact angle hysteresis. It is shown that the most stable contact angle is very well described by the Cassie equation, since the drops arc much larger than the scale of chemical heterogeneity of the SAM surfaces. In addition, it is demonstrated that contact angle hysteresis is sensitive to the chemical heterogeneity of the surface, even at the nanometric scale.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-51384 (URN)10.1021/la9016992 (DOI)
Available from: 2009-10-30 Created: 2009-10-30 Last updated: 2017-01-11
Ederth, T., Nygren, P., Ekblad, T., Östblom, M., Liedberg, B., Pettitt, M., . . . Callow, J. (2007). Interactions of algal spores and diatoms with mixed synthetic peptide SAMs. In: : . Paper presented at LB12 - The 12th International Conference on Organized Molecular Films, July 1 - 5, 2007, Krákow, Poland.
Open this publication in new window or tab >>Interactions of algal spores and diatoms with mixed synthetic peptide SAMs
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2007 (English)Conference paper, Poster (with or without abstract) (Other academic)
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-44508 (URN)76919 (Local ID)76919 (Archive number)76919 (OAI)
Conference
LB12 - The 12th International Conference on Organized Molecular Films, July 1 - 5, 2007, Krákow, Poland
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-01-11Bibliographically approved
Li, W., Östblom, M., Xu, L., Hellsten, A., Leanderson, P., Liedberg, B., . . . Yuan, X. (2006). Cytocidal effects of atheromatous plaque components: The death zone revisited. The FASEB Journal, 20(13), 2281-2290
Open this publication in new window or tab >>Cytocidal effects of atheromatous plaque components: The death zone revisited
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2006 (English)In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 20, no 13, p. 2281-2290Article in journal (Refereed) Published
Abstract [en]

Objective: Earlier we suggested that atheroma lesions constitute a "death zone" containing toxic materials that may cause dysfunction and demise of invading macrophages to prevent the removal of plaque materials. Here we have assessed the cytotoxic effects of nonfractionated gruel and insoluble (ceroid-like) material derived from advanced human atheroma. Methods and Results: The insoluble material within advanced atherosclerotic plaque was isolated following protease K digestion and extensive extraction with aqueous and organic solvents. FTIR, Raman, and atomic absorption spectroscopy suggested that, despite its fluorescent nature, this material closely resembled hydroxyapatite and dentin, but also contained a significant amount of iron and calcium. When added to J774 cells and human macrophages in culture, this insoluble substance was phagocytosed, and progressive cell death followed. However, an even more cytotoxic activity was found in the atheromatous "gruel" that contains abundant carbonyls/aldehydes. Cell death caused by both crude gruel and ceroid could be blocked by preincubating cells with the lipophilic iron chelator salicylaldehyde isonicotinoyl hydrazone, apoferritin, BAPTA/AM, or sodium borohydride, indicating that cellular iron, calcium, and reactive aldehyde(s) are responsible for the observed cytotoxicity. Conclusions: Toxic materials within atheromatous lesions include both ceroid and even more cytotoxic lipidaceous materials. The cytotoxic effects of these plaque components may help explain the persistence of atherosclerotic lesions. © FASEB.

Keywords
Apoferritin, Apoptosis, Atherosclerosis, Carbonyls, Ceroid, Iron, Macrophages
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-50100 (URN)10.1096/fj.06-6114com (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Li, W., Östblom, M., Xu, L., Hellsten, A., Leanderson, P., Liedberg, B., . . . Yuan, X. M. (2006). Cytocidal effects of atheromatous plaque components: the death zone revisited.. The FASEB Journal, 20, 2281-2290
Open this publication in new window or tab >>Cytocidal effects of atheromatous plaque components: the death zone revisited.
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2006 (English)In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 20, p. 2281-2290Article in journal (Refereed)
Abstract [en]

   

Identifiers
urn:nbn:se:liu:diva-35728 (URN)28331 (Local ID)28331 (Archive number)28331 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
Östblom, M., Valiokas, R., Konradsson, P., Svensson, S., Liedberg, B., Garrett, M. & Allara, D. (2006). Ice nucleation and phase behavior on oligo(ethylene glycol) and hydroxyl self-assembled monolayers: Simulations and experiments. Journal of Physical Chemistry B, 110(4), 1830-1836
Open this publication in new window or tab >>Ice nucleation and phase behavior on oligo(ethylene glycol) and hydroxyl self-assembled monolayers: Simulations and experiments
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2006 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 4, p. 1830-1836Article in journal (Refereed) Published
Abstract [en]

The nucleation and phase behavior of ultrathin D2O-ice overlayers have been studied on oligo(ethylene glycol) (OEG)-terminated and hydroxyl self-assembled monolayers (SAMs) at low temperatures in ultrahigh vacuum. Infrared reflection-absorption spectroscopy (IRAS) is used to characterize the ice overlayers, the SAMs, and the interactions occurring between the ice and the SAM surfaces. Spectral simulations, based on optical models in conjunction with Maxwell Garnett effective medium theory, point out the importance of including voids in the modeling of the ice structures, with void fractions reaching 60% in some overlayers. The kinetics of the phase transition from amorphous-like to crystalline-like ice upon isothermal annealing at 140 K is found to depend on the conformational state of the supporting OEG SAM surface. The rate is fast on the helical OEG SAMs and slow on the corresponding all-trans SAMs. This difference in kinetics is most likely due to a pronounced D2O interpenetration and binding to the all-trans segments of the ethylene glycol portion of the SAM. No such penetration and binding was observed on the helical OEG SAM. © 2006 American Chemical Society.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-50302 (URN)10.1021/jp056007q (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Valiokas, R., Östblom, M., Björefors, F., Liedberg, B., Shi, J. & Konradsson, P. (2006). Structural and kinetic properties of laterally stabilized, oligo(ethylene glycol)-containing alkylthiolates on gold: A modular approach. Biointerphases, 1(1), 22-34
Open this publication in new window or tab >>Structural and kinetic properties of laterally stabilized, oligo(ethylene glycol)-containing alkylthiolates on gold: A modular approach
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2006 (English)In: Biointerphases, ISSN 1934-8630, E-ISSN 1559-4106, Vol. 1, no 1, p. 22-34Article in journal (Refereed) Published
Abstract [en]

The formation of highly ordered self-assembled monolayers (SAMs) on goldfrom an unusually long and linear compound HS(CH2)15CONH(CH2CH2O)6CH2CONH(CH2)15CH3 is investigated by contact angle goniometry, ex situ null ellipsometry, cyclic voltammetry and infrared reflection-absorption spectroscopy. The molecules are found to assemble in an upright position as a complete monolayer within 60 min. The overall structure of the SAM reaches equilibrium within 24 h as evidenced by infrared spectroscopy, although a slight improvement in water contact angles is observed over a period of a few weeks. The resulting SAM is 60 Å thick and it displays an advancing water contact angle of 112° and excellent electrochemicalblocking characteristics with typical current densities about 20 times lower as compared to those observed for HS(CH2)15CH3 SAMs. The dominating crystalline phases of the supporting HS(CH2)15 and terminal (CH2)15CH3 alkyl portions, as well as the sealed oligo(ethylene glycol) (OEG) “core,” appear as unusually sharp features in the infrared spectra at room temperature. For example, the splitting seen for the CH3 stretching and CH2 scissoring peaks is normally only observed for conformationally trapped alkylthiolate SAMs at low temperatures and for highly crystalline polymethylenes. Temperature-programmed infrared spectroscopy in ultrahigh vacuum reveals a significantly improved thermal stability of the SAM under investigation, as compared to two analogous OEG derivatives without the extended alkyl chain. Our study points out the advantages of adopting a “modular approach” in designing novel SAM-forming compounds with precisely positioned in plane stabilizing groups. We demonstrate also the potential of using the above set of compounds in the fabrication of “hydrogel-like” arrays with controlled wetting properties for application in the ever-growing fields of protein and cell analysis, as well as for bioanalytical applications.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2006
National Category
Physical Chemistry
Identifiers
urn:nbn:se:liu:diva-33872 (URN)10.1116/1.2188521 (DOI)000203008000008 ()20408612 (PubMedID)19947 (Local ID)19947 (Archive number)19947 (OAI)
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2018-05-30Bibliographically approved
Östblom, M., Ekeroth, J., Konradsson, P. & Liedberg, B. (2006). Structure and desorption energetics of ultrathin D2O ice overlay ers on serine- And serinephosphate-terminated self-assembled monolayers. Journal of Physical Chemistry B, 110(4), 1695-1700
Open this publication in new window or tab >>Structure and desorption energetics of ultrathin D2O ice overlay ers on serine- And serinephosphate-terminated self-assembled monolayers
2006 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 4, p. 1695-1700Article in journal (Refereed) Published
Abstract [en]

This paper reports on the structure and desorption dynamics of thin D 2O ice overlayers (0.2-10 monolayers) deposited on serine- and serinephosphate- (with H+, Na+, Ca2+ counterions) terminated self-assembled monolayers (SAMs). The D2O ice overlayers are deposited on the SAMs at ~85 K in ultrahigh vacuum and characterized with infrared reflection absorption spectroscopy (IRAS). Reflection absorption (RA) spectra obtained at sub-monolayer D2O coverage reveal that surface modes, e.g. free dangling OD stretch, dominate on the serine SAM surface, whereas vibrational modes characteristic for bulk ice are more prominent on the serinephosphate SAMs. Temperature programmed desorption mass spectrometry (TPD-MS) and TPD-IRAS are subsequently used to investigate the energetics and the structural transitions occurring in the ice overlayer during temperature ramping. D2O ice (~2.5 monolayers) on the serine SAMs undergoes a gradual change from an amorphous- to a crystalline-like phase upon increasing the substrate temperature. This transition is not as pronounced on the serine phosphate SAM most likely because of reduced mobility due to strong pinning to the surface. We show also that the energy of desorption for a sub-monolayer of D2O ice on serinephosphate SAM surfaces with a Na+ and Ca2+ counterions is equally high or even exceeds previously reported values for analogous high-energy SAMs. © 2006 American Chemical Society.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-50301 (URN)10.1021/jp055169j (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Riepl, M., Östblom, M., Lundström, I., Svensson, S., Van, D. G. .., Schaferling, M. & Liedberg, B. (2005). Molecular gradients: An efficient approach for optimizing the surface properties of biomaterials and biochips. Langmuir, 21(3), 1042-1050
Open this publication in new window or tab >>Molecular gradients: An efficient approach for optimizing the surface properties of biomaterials and biochips
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2005 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 21, no 3, p. 1042-1050Article in journal (Refereed) Published
Abstract [en]

A variety of molecular gradients of alkanethiols with the structure HS-(CH2)m-X (m = 15, X = COOH, CH2NH 2, or CH3) and oligo(ethylene glycol)-terminated alkanethiols with the structures HS-(CH2)15-CO-NH-Eg n (n = 2, 4, or 6), HS-(CH2)15-CO-NH-Eg 2-(CH2)2-NH-CO-(CH2) 4-biotin, and HS-(CH2)15-CO-NH-Eg 6-CH2-COOH were prepared on polycrystalline gold films. These gradients were designed to serve as model surfaces for fundamental studies of protein adsorption and immobilization phenomena. Ellipsometry, infrared spectroscopy, and X-ray photoelectron spectroscopy, operating in scanning mode, were used to monitor the layer composition, gradient profiles, tail group conformation, and overall structural quality of the gradient assemblies. The gradient profiles were found to be 4-10 mm wide, and they increased in width with increasing difference in molecular complexity between the thiols used to form the gradient. The oligo(ethylene glycol) thiols are particularly interesting because they can be used to prepare so-called conformational gradients, that is, gradients that display a variation in oligo(ethylene glycol) chain conformation from all trans on the extreme Eg 2,4 sides, via an amorphous-like phase in the mixing regimes, to helical at the extreme Eg6 sides. We demonstrate herein a series of experiments where the above gradients are used to evaluate nonspecific binding of the plasma protein fibrinogen, and in agreement with previous studies, the highest amounts of nonspecifically bound fibrinogen were observed on all-trans monolayers, that is, on the extreme Eg2,4 sides. Moreover, gradients between Eg2 and a biotinylated analogue have been prepared to optimize the conditions for the immobilization of streptavidin. Ellipsometry and infrared spectroscopy reveal high levels of immobilization over a fairly broad range of compositions in the gradient regime, with a maximum between 50 and 60% of the biotinylated analogue in the monolayer. A pi gradient composed of (NH3+/COO-)-terminated thiols was also prepared and evaluated with respect to its ability to separate differently charged proteins, pepsin, and lysozyme, on a solid surface.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-45519 (URN)10.1021/la048358m (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13
Östblom, M., Liedberg, B., Demers, L. & Mirkin, C. (2005). On the structure and desorption dynamics of DNA bases adsorbed on gold: A temperature-programmed study. Journal of Physical Chemistry B, 109(31), 15150-15160
Open this publication in new window or tab >>On the structure and desorption dynamics of DNA bases adsorbed on gold: A temperature-programmed study
2005 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, no 31, p. 15150-15160Article in journal (Refereed) Published
Abstract [en]

The structure and desorption dynamics of mono- and multilayer samples of adenine, cytosine, guanine, and thymine on polycrystalline gold thin films are studied using temperature-programmed desorption-infrared reflection absorption spectroscopy (TPD-IRAS) and temperature-programmed desorption-mass spectroscopy (TPD-MS). It is shown that the pyrimidines, adenine and guanine, adsorb to gold in a complex manner and that both adhesive (adenine) and cohesive (guanine) interactions contribute the apparent binding energies to the substrate surface. Adenine displays at least two adsorption sites, including a high-energy site (210°C, ~136 kj/mol), wherein the molecule coordinates to the gold substrate via the NH2 group in an sp3-like, strongly perturbed, nonplanar configuration. The purines, cytosine and thymine, display a less complicated adsorption/desorption behavior. The desorption energy for cytosine (160°C, ~122 kJ/mol) is similar to those obtained for adenine and guanine, but desorption occurs from a single site of dispersed, nonaggregated cytosine. Thymine desorbs also from a single site but at a significantly lower energy (100°C, ~104 kJ/mol). Infrared data reveal that the monolayer architectures discussed herein are structurally very different from those observed for the bases in the bulk crystalline state. It is also evident that both pyrimidines and purines adsorb on gold with the plane of the molecule in a nonparallel orientation with respect to the substrate surface. The results of this work are discussed in the context of improving the understanding of the design of capturing oligonucleotides or DNA strands for bioanalytical applications, in particular, for gold nanoparticle-based assays. © 2005 American Chemical Society.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-50440 (URN)10.1021/jp051617b (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Wang, X., Östblom, M., Johansson, T. & Inganäs, O. (2004). PEDOT surface energy pattern controls fluorescent polymer deposition by dewetting. Thin Solid Films, 449(1-2), 125-132
Open this publication in new window or tab >>PEDOT surface energy pattern controls fluorescent polymer deposition by dewetting
2004 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 449, no 1-2, p. 125-132Article in journal (Refereed) Published
Abstract [en]

An elastomeric stamp of poly(dimethylsiloxane) (PDMS) can modify the surface energy of some surfaces when brought into conformal contact with these for some time. The substrates under investigation are a conducting polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) and a polyelectrolyte poly(sodium 4-styrenesulfonate) (NaPSS). The changes in surface wetting are characterized by contact angle measurement. Changes are due to the PDMS stamp, which leaves low molecular weight residues on the surface, as shown by infrared reflection absorption spectroscopy. This process may also be operating when other inks are transferred in microcontact printing. Patterning of fluorescent polymer film with feature size of 10–100 μm range is done by confining polymer solutions on the modified surface, by means of spin- or dip-coating. The profile of the patterned film and factors that influence the profile are discussed. This technique is a convenient way to build polymer microstructures for application in organic and biomolecular electronics and photonics.

Keywords
Surface energy, Surface modification by PDMS stamp, Contact angle analysis, IRA spectrum, Polymer patterning
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-13884 (URN)10.1016/j.tsf.2003.10.153 (DOI)
Available from: 2006-07-07 Created: 2006-07-07 Last updated: 2018-10-08
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