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Vahlberg, Cecillia
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Publications (10 of 23) Show all publications
Lindell, L., Vahlberg, C., Uvdal, K., Fahlman, M. & Braun, S. (2015). Self-assembled monolayer engineered interfaces: Energy level alignment tuning through chain length and end-group polarity. Journal of Electron Spectroscopy and Related Phenomena, 204, 140-144
Open this publication in new window or tab >>Self-assembled monolayer engineered interfaces: Energy level alignment tuning through chain length and end-group polarity
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2015 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 204, p. 140-144Article in journal (Refereed) Published
Abstract [en]

We explore the different mechanisms through which self-assembled monolayers can tailor energy level alignment at metal-organic semiconductor interfaces. We show that the large work function variation that can be induced by the self-assembled monolayer on gold has limited ability to tailor the interface energy level alignment of a subsequent organic semiconductor overlayer. (C) 2015 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2015
Keywords
Self-assembled monolayer; SAM; F4-TCNQ; Interfaces; Energy level alignment
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-122663 (URN)10.1016/j.elspec.2015.04.006 (DOI)000363078400017 ()
Note

Funding Agencies|Swedish Energy Agency, STEM; Swedish Research Council [2013-4022]; Goran Gustafsson Foundation

Available from: 2015-11-16 Created: 2015-11-13 Last updated: 2017-12-01
Vahlberg, C., Linares, M., Norman, P. & Uvdal, K. (2012). Phenylboronic Ester- and Phenylboronic Acid-Terminated Alkanethiols on Gold Surfaces. The Journal of Physical Chemistry C, 116(1), 796-806
Open this publication in new window or tab >>Phenylboronic Ester- and Phenylboronic Acid-Terminated Alkanethiols on Gold Surfaces
2012 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 1, p. 796-806Article in journal (Refereed) Published
Abstract [en]

In this work, it is shown that a well-organized monolayer of phenylboronic ester-terminated thiol (BOR-capped) on gold surfaces can be prepared. Our results also show that the BOR-capped molecular system can be cleaved directly on the surface, resulting in an unprotected BOR-uncapped monolayer with the boronic acid functional groups available for coordination to diol molecules in the ambient media. The monolayers of BOR-capped and BOR-uncapped were characterized using infrared spectroscopy, near edge X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy, ellipsometry, and contact angle goniometry. The X-ray photoelectron spectroscopy results showed that both BOR-capped and BOR-uncapped are chemically linked to the gold substrate. According to the infrared spectroscopy results, the main component of the CO vibrational mode present in the amide moiety is perpendicular oriented relative to the gold surface normal for the BOR-capped molecular system. The near edge X-ray absorption fine structure spectroscopy resonance peak located at approximately 285 eV, assigned to pi(1)* transitions, was used to estimate the average tilt angle of the vector parallel to the pi* orbitals of the aromatic ring relative to the gold surface normal. The average tilt angle is estimated to be approximately 63 degrees for the BOR-capped monolayer on gold surfaces. The aromatic ring of the BOR-uncapped molecule has a more tilted orientation compared to the BOR-capped one. The experimental infrared spectroscopy and near edge X-ray absorption fine structure spectroscopy results were supported with theoretical modeling including calculations of vibrational modes and of excitation processes.

Place, publisher, year, edition, pages
American Chemical Society, 2012
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-75282 (URN)10.1021/jp208597x (DOI)000298978700098 ()
Note

Funding Agencies|Swedish research council Carl Tryggers Foundation|621-2010-5014|CeNano at LiU||

Available from: 2012-02-27 Created: 2012-02-24 Last updated: 2017-12-07
Vahlberg, C., Linares, M., Villaume, S., Norman, P. & Uvdal, K. (2011). Noradrenaline and a Thiol Analogue on Gold Surfaces: An Infrared Reflection-Absorption Spectroscopy, X-ray Photoelectron Spectroscopy, and Near-Edge X-ray Absorption Fine Structure Spectroscopy Study. The Journal of Physical Chemistry C, 115(1), 165-175
Open this publication in new window or tab >>Noradrenaline and a Thiol Analogue on Gold Surfaces: An Infrared Reflection-Absorption Spectroscopy, X-ray Photoelectron Spectroscopy, and Near-Edge X-ray Absorption Fine Structure Spectroscopy Study
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2011 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 115, no 1, p. 165-175Article in journal (Refereed) Published
Abstract [en]

Self-assembled monolayers and multilayers of a noradrenaline analogue (Nor-Pt) on gold substrates as well as multilayers of noradrenaline have been investigated by means of the molecular orientation, the molecule surface interaction, the molecular composition and the functional group availability for further biointeraction processes, using X-ray photoelectron spectroscopy (XPS), infrared reflection absorption spectroscopy (IRAS), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. A chemical shift (1.7 eV) of the S 2p peak to lower binding energies is observed, in the XPS spectrum, indicating that the Nor-Pt molecules are chemisorbed onto the gold substrate. The IR results show that Nor-Pt adsorbate has the C=O stretching vibration modes parallel oriented relative to the gold substrate. The average tilt angle of the aromatic ring relative to the gold surface normal is determined to be approximately 51 degrees, based on the NEXAFS measurements on Nor-Pt monolayers. The experimental results and assignments are supported with theoretical studies where we use the building block principle in the spectral analysis and compare with the measurements of noradrenaline and Nor-Pt. The theoretical calculations are shown to be useful; for angle dependence NEXAFS studies as resonances with fully pi* or sigma* character are preferred for correct analysis.

Place, publisher, year, edition, pages
American Chemical Society, 2011
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-66293 (URN)10.1021/jp105696j (DOI)000285818200024 ()
Available from: 2011-03-11 Created: 2011-03-11 Last updated: 2017-12-11Bibliographically approved
Vahlberg, C. (2011). Structure analysis and molecular recognition studies of bio-functionalized surfaces. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Structure analysis and molecular recognition studies of bio-functionalized surfaces
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Biological and chemical reactions involved in physiological processes are often complex and very sophisticated. Such processes can be mimicked in the laboratory to obtain important knowledge, valuable for the  development of new diagnostic methods, drugs and biosensors. This  thesis includes investigations of bio-functionalized surfaces that can be used as model systems to mimic naturally existing biomolecular recognition processes.

In this thesis, three different peptides, of our own design, that mimic parts of the second and third intracellular loops of the α2A-adrenergic receptor, are studied. The peptides were immobilized onto gold substrates, through thiol chemistry. The interaction between the peptides and the G-protein was investigated using surface plasmon resonance (SPR). The G-protein showed the highest binding capability for surfaces functionalized with a peptide mimicking the n-terminal of the third intracellular loop (GPR-i3n). The binding was enhanced when the pure GPR-i3n peptide was mixed with a short oligopeptide (3GC). A tentative explanation for the obtained results is that the presence of the 3GC molecule enables conformational changes of the GPR-i3n monolayer which affect the interaction with the G-protein. The results from the SPR measurements also indicated that the conformation of the G-protein was kept intact during the interaction with a peptide mimicking the c-terminal of the third intracellular loop (GPR-i3c). Multilayers were formed on the surfaces functionalized with a peptide mimicking the second intracellular loop (GPR-i2c) and the GPR-i3n peptide. We suggest that conformational changes of the G-protein are induced during the interaction with the surfaces functionalized with the GPR-i3n and GPR-i2c peptides.

Comprehensive surface characterizations of four biomolecular systems, based upon the functional groups: noradrenaline, phenylboronic-ester, phenylboronic-acid and benzenesulfonamide, are presented in the thesis. The aim is to develop a platform for detailed molecular recognition studies on surfaces. The molecular systems were characterized using infrared spectroscopy, X-ray photoelectron spectroscopy, near edge X-ray absorption fine structure spectroscopy, ellipsometry and contact angle goniometry. Noradrenaline was chosen as it is a neurotransmitter that interacts with the extracellular loops of adrenergic receptors. In this work, the noradrenaline analogue (Nor-Pt) of our own design, was equipped with a -SH handle to be linked to surfaces and with the free noradrenaline group available for interaction studies. The Nor-Pt molecules were organized on the surfaces with the sulfur atom close to the gold substrate and the aromatic ring available for possible interactions with other biomolecules in the ambient media. The main component of the C=O vibrational mode present in the amide moiety had a parallel orientation relative to the plane of the gold surface, based on the infrared spectroscopy results. The phenylboronic system was designed as a simple mimicry of an  adrenergic receptor as the boronic acid functional group binds to diol containing molecules such as noradrenaline. The boronic  esterterminated alkane thiol (BOR-Capped) was chemisorbed onto gold substrates. We showed that BOR-Capped was linked to the gold substrate via thiolate bond formation and formed a well-organized monolayer. The pinacolyl protection group was removed directly from the BOR-Capped monolayer on the surfaces, which resulted in an unprotected monolayer terminated with the boronic acid functional group (BOR-Uncapped). The strong chemical bond to the gold substrate was retained during the deprotection procedure as only thiolate sulfur species were observed for the BOR-Uncapped molecular system. The benzenesulfonamide based molecule was designed as a model system for bioselective surfaces. An amine-terminated alkane thiol was adsorbed onto a gold substrate. In a second step, a benzenesulfonamide derivative was linked to the amine-terminated monolayer by the formation of an amide bond. We showed that the resulting benzenesulfonamide-terminated alkane thiol (AUT-C6) formed a well-organized and semi-thick monolayer on the gold substrate. The polarization dependence of NEXAFS was used to determine the average tilt angle of the aromatic ring structures of Nor-Pt, BOR-Capped, BOR-Uncapped and AUT-C6. The results indicate that the aromatic ring planes of BOR-Capped and AUT-C6 have a preferential orientation toward the surface normal. The aromatic ring structures of Nor-Pt and BOR-Uncapped were determined to have a more tilted orientation relative to the gold surface normal.

Finally, the interaction between carbonic anhydrase and the AUT-C6 molecule was investigated using surface plasmon resonance and ellipsometry. The surface immobilized benzenesulfonamide was shown to bind to carbonic anhydrase and the results indicated that the interaction is specific.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2011. p. 56
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1404
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-71457 (URN)9789173930505 (ISBN)
Public defence
2011-11-11, Planck, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 10:15 (Swedish)
Opponent
Supervisors
Available from: 2011-10-19 Created: 2011-10-19 Last updated: 2017-12-15Bibliographically approved
Selegård, L., Khranovskyy, V., Söderlind, F., Vahlberg, C., Ahrén, M., Käll, P.-O., . . . Uvdal, K. (2010). Biotinylation of ZnO Nanoparticles and Thin Films: A Two-Step Surface Functionalization Study. ACS APPLIED MATERIALS and INTERFACES, 2(7), 2128-2135
Open this publication in new window or tab >>Biotinylation of ZnO Nanoparticles and Thin Films: A Two-Step Surface Functionalization Study
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2010 (English)In: ACS APPLIED MATERIALS and INTERFACES, ISSN 1944-8244, Vol. 2, no 7, p. 2128-2135Article in journal (Refereed) Published
Abstract [en]

This study reports ZnO nanoparticles and thin film surface modification using a two-step functionalization strategy. A small silane molecule was used to build up a stabilizing layer and for conjugation of biotin (vitamin B7), as a specific tag. Biotin was chosen because it is a well-studied bioactive molecule with high affinity for avidin. ZnO nanoparticles were synthesized by electrochemical deposition under oxidizing condition, and ZnO films were prepared by plasma-enhanced metal organic chemical vapor deposition. Both ZnO nanoparticles and ZnO thin films were surface modified by forming a (3-mercaptopropyl)trimethoxysilane (MPTS) layer followed by attachment of a biotin derivate. lodoacetyl-PEG2-biotin molecule was coupled to the thiol unit in MPTS through a substitution reaction. Powder X-ray diffraction, transmission electron microscopy, X-ray photoemission electron microscopy, atomic force microscopy. X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure spectroscopy were used to investigate the as-synthesized and functionalized ZnO materials. The measurements showed highly crystalline materials in both cases with a ZnO nanoparticle diameter of about 5 nm and a grain size of about 45 nm for the as-grown ZnO thin films. The surface modification process resulted in coupling of silanes and biotin to both the ZnO nanoparticles and ZnO thin films. The two-step functionalization strategy has a high potential for specific targeting in bioimaging probes and for recognition studies in biosensing applications.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA, 2010
Keywords
ZnO nanoparticles, thin films XRD, TEM, XPS, NEXAFS, biotin, PEEM
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-58542 (URN)10.1021/am100374z (DOI)000280367000049 ()
Available from: 2010-08-13 Created: 2010-08-13 Last updated: 2015-05-29
Kanungo, J., Selegård, L., Vahlberg, C., Uvdal, K., Saha, H. & Basu, S. (2010). XPS study of palladium sensitized nano porous silicon thin film. BULLETIN OF MATERIALS SCIENCE, 33(6), 647-651
Open this publication in new window or tab >>XPS study of palladium sensitized nano porous silicon thin film
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2010 (English)In: BULLETIN OF MATERIALS SCIENCE, ISSN 0250-4707, Vol. 33, no 6, p. 647-651Article in journal (Refereed) Published
Abstract [en]

Nano porous silicon (PS) was formed on p-type monocrystalline silicon of 2-5 Omega cm resistivity and (100) orientation by electrochemical anodization method using HF and ethanol as the electrolytes. High density of surface states, arising due to its nano structure, is responsible for the uncontrolled oxidation in air and for the deterioration of the PS surface with time. To stabilize the material PS surface was modified by a simple and low cost chemical method using PdCl2 solution at room temperature. X-ray photoelectron spectroscopy (XPS) was performed to reveal the chemical composition and the relative concentration of palladium on the nanoporous silicon thin films. An increase of SiO2 formation was observed after PdCl2 treatment and presence of palladium was also detected on the modified surface. I-V characteristics of Al/PS junction were studied using two lateral Al contacts and a linear relationship was obtained for Pd modified PS surface. Stability of the contact was studied for a time period of around 30 days and no significant ageing effect could be observed.

Place, publisher, year, edition, pages
Indian Academy of Sciences; 1999 / Indian Academy of Sciences, Springer, 2010
Keywords
Porous silicon, passivation, palladium, oxidation, XPS
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-67029 (URN)10.1007/s12034-011-0138-9 (DOI)000288185200001 ()
Available from: 2011-03-25 Created: 2011-03-25 Last updated: 2015-05-29
Savitchi, L., Vahlberg, C., Petoral, R. J. & Uvdal, K. (2007). Mixed monolayers to promote G-protein adsorption: α2A- Adrenergic receptor-derived peptides coadsorbed with formyl-terminated oligopeptides. Langmuir, 23(16), 8474-8479
Open this publication in new window or tab >>Mixed monolayers to promote G-protein adsorption: α2A- Adrenergic receptor-derived peptides coadsorbed with formyl-terminated oligopeptides
2007 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 23, no 16, p. 8474-8479Article in journal (Refereed) Published
Abstract [en]

Pure and mixed monolayers of a synthetic peptide, GPR-i3n, derived from the third intracellular loop of the α2 adrenergic receptor and a shorter inactive oligopeptide, N-formyl-(Gly)3-(Cys) (called 3GC), were prepared on gold surfaces. The mixing ratio of the GPR-i3n and 3GC was used to control G-protein binding capability. The GPR-i3n peptide is specially designed for bovine G-protein selectivity and has been proven to have high affinity to G-proteins [Vahlberg, C.; Petoral, R. M., Jr.; Lindell, C.; Broo, K.; Uvdal, K. Langmuir 2006, 22 (17), 7260−7264]. Pure 3GC monolayers show very low protein adsorption capability. In this study, 3GC is chosen as a coadsorbent, with the aim to induce molecular conformational changes during monolayer formation to enhance G-protein adsorption. A full characterization of the mixed monolayers was done. The monolayer thickness and the mass-related surface coverage for both GPR-i3n and 3GC were investigated using radio labeling. The GPR-i3n was labeled by 125I-targeting tyrosine, and the activity was measured by using radioimmunoassay (RIA). The formation and chemical composition of GPR-i3n and 3GC monolayers were investigated using X-ray photoelectron spectroscopy, and it is shown that both GPR-i3n and 3GC bind chemically to the gold surface. The interaction between the mixed monolayers and G-proteins was investigated by means of real-time surface plasmon resonance. There is a higher protein binding capacity to the monolayer when the GPR-i3n peptide is intermixed with the 3GC coadsorbent, despite the fact that the 3GC itself has a very low G-protein binding capability. This supports a molecular reorientation at the surface, while 3GC is intermixed with GPR-i3n.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-47944 (URN)10.1021/la063447f (DOI)000248229900028 ()
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13Bibliographically approved
Vahlberg, C., Petoral, R. J., Carlsson, A., Broo, K. & Uvdal, K. (2007). Neurotransmitter Derivatives Adsorbed on Gold. In: IVC-17/ICSS-13 ICNT,2007.
Open this publication in new window or tab >>Neurotransmitter Derivatives Adsorbed on Gold
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2007 (English)In: IVC-17/ICSS-13 ICNT,2007, 2007Conference paper, Published paper (Other academic)
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-44595 (URN)77165 (Local ID)77165 (Archive number)77165 (OAI)
Note
Conference proceedingsAvailable from: 2009-10-10 Created: 2009-10-10
Yakimova, R., Steinhoff, G., Petoral, R. J., Vahlberg, C., Khranovskyy, V., Yazdi, G., . . . Lloyd Spetz, A. (2007). Novel material concepts of transducers for chemical and biosensors. Biosensors & bioelectronics, 22(12), 2780-2785
Open this publication in new window or tab >>Novel material concepts of transducers for chemical and biosensors
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2007 (English)In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 22, no 12, p. 2780-2785Article in journal (Refereed) Published
Abstract [en]

The objectives of this work are to contribute to the knowledge about physical and chemical properties of WBG semiconductors, such as ZnO and GaN towards development of advanced bio- and chemical sensors. For the semiconductors, growth techniques typically yielding single crystal material are applied. Thin epitaxial quality films of ZnO and GaN are fabricated on SiC or sapphire substrates. An emphasis is given to ZnO due to the interesting combination of the semiconductor and oxide properties. Surface bio-functionalization of ZnO is performed by APTES, MPA or MP-TMS molecules. We have compared some of the results to (hydroxylated) GaN surfaces functionalized by MP-TMS. The covalent attachment of the self-assembled biomolecular layers has been proven by XPS analysis. For complementary electrical characterization impedance spectroscopy measurements were performed. The results are intended to serve the realization of bioelectronic transducer devices based on SiC or GaN transistors with a ZnO gate layer. To take advantage of the catalytic properties of ZnO, initial prototypes of chemical sensors for gas sensing are processed on ZnO deposited either on SiC or on sapphire and they are further tested for the response to reducing or oxidizing gas ambient. The sensor devices show sensitivity to oxygen in the surface resistivity mode while a Pt Schottky contact ZnO/SiC device responds to reducing gases. These results are compared to published results on Pt/GaN Schottky diodes. © 2007 Elsevier B.V. All rights reserved.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-38763 (URN)10.1016/j.bios.2006.12.032 (DOI)45537 (Local ID)45537 (Archive number)45537 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
Yakimova, R., Petoral, R. J., Yazdi, G., Vahlberg, C., Lloyd Spetz, A. & Uvdal, K. (2007). Surface functionalization and biomedical applications based on SiC. Journal of Physics D: Applied Physics, 40(20), 6435-6442
Open this publication in new window or tab >>Surface functionalization and biomedical applications based on SiC
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2007 (English)In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 40, no 20, p. 6435-6442Article in journal (Refereed) Published
Abstract [en]

The search for materials and systems, capable of operating long term under physiological conditions, has been a strategy for many research groups during the past years. Silicon carbide (SiC) is a material, which can meet the demands due to its high biocompatibility, high inertness to biological tissues and to aggressive environment, and the possibility to make all types of electronic devices. This paper reviews progress in biomedical and biosensor related research on SiC. For example, less biofouling and platelet aggregation when exposed to blood is taken advantage of in a variety of medical implantable materials while the robust semiconducting properties can be explored in surface functionalized bioelectronic devices. © 2007 IOP Publishing Ltd.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-38765 (URN)10.1088/0022-3727/40/20/S20 (DOI)45539 (Local ID)45539 (Archive number)45539 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
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