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Lindholm-Sethson, Britta
Publications (10 of 34) Show all publications
Khani Meynaq, M. Y., Lindholm-Sethson, B. & Tesfalidet, S. (2018). Cationic Interaction with Phosphatidylcholine in a lipid cubic phase studied with electrochemical impedance spectroscopy and Small Angle X-ray Scattering. Journal of Colloid and Interface Science, 528, 321-329
Open this publication in new window or tab >>Cationic Interaction with Phosphatidylcholine in a lipid cubic phase studied with electrochemical impedance spectroscopy and Small Angle X-ray Scattering
2018 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 528, p. 321-329Article in journal (Refereed) Published
Abstract [en]

Hypothesis: Electrochemical Impedance Spectroscopy (EIS) can be used to investigate cationic interaction with the choline headgroup in the ternary system of monoolein/dioleoylphosphatidylcholine/water (MO/DOPC/H2O).

Experiments: EIS was used to estimate the resistance and capacitance of a freestanding membrane of a lipid cubic phase (LCP). The membrane was formed in a small cylindrical aperture separating two compartments, containing one Pt electrode each. The impedance experiments were carried out in a two electrode setup with electrolyte solutions made of KCl, CsCl, MgCl2 and CaCl2 filling the compartments at two different ionic strength. Small angle X-ray diffraction (SAXRD) was used to establish the structure and cell unit parameters of the LCP.

Findings: The interpretation of ionic interaction with phosphatidylcholine was based on estimated membrane resistances and capacitances from EIS measurements. The magnitude of cationic interaction with the lipid headgroup in the water channels is correlated to the membrane resistance that increases in the order Cs+ < K+ < Mg2+ < Ca2+ following the Hofmeister direct series and also reflecting the order of intrinsic binding constants. The membrane capacitance and SAXRD results are discussed as an effect of cationic interaction and it was possible to observe both swelling and condensing effects. The stability of the cubic phase throughout the experiments was confirmed by SAXRD.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-148292 (URN)10.1016/j.jcis.2018.05.065 (DOI)000440127000034 ()
Available from: 2018-06-01 Created: 2018-06-01 Last updated: 2018-09-04Bibliographically approved
Phal, S., Shatri, B., Berisha, A., Geladi, P., Lindholm-Sethson, B. & Tesfalidet, S. (2018). Covalently electrografted carboxyphenyl layers onto gold surface serving as a platform for the construction of an immunosensor for detection of methotrexate. Journal of Electroanalytical Chemistry, 812, 235-243
Open this publication in new window or tab >>Covalently electrografted carboxyphenyl layers onto gold surface serving as a platform for the construction of an immunosensor for detection of methotrexate
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2018 (English)In: Journal of Electroanalytical Chemistry, ISSN 1572-6657, Vol. 812, p. 235-243Article in journal (Refereed) Published
Abstract [en]

Abstract The classical way to modify a gold electrode surface for immunosensor development is through self-assembly of functionalised thiols for subsequent attachment of antibodies. Here is described a new pathway for surface modification using a diazonium salt-based immunosensor for detection of methotrexate (MTX) with electrochemical immittance spectroscopy (EIS). The diazonium salt, 4-carboxybenzenediazonium tetrafluoroborate was synthesized using a diazotization reaction and characterized by IR and cyclic voltammetry (CV). The Au electrode was electrografted with diazonium and used for anti-MTX antibody immobilization. The EIS detection of MTX was studied with and without application of redox probe; Fe(CN)63−/4−. MTX could not be detected using Fe(CN)63−/4−as redox probe, whereas EIS measurements without redox probe and analysis of the data with singular decomposition (SVD) gave good results. A multivariate calibration model showed good linear behavior on a logarithmic scale with a detection limit for MTX of 7×10−12molL−1.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
4-carboxybenzenediazonium tetrafluoroborate, Gold electrode, Antibody, Immunosensor, Singular value decomposition, Cyclic voltammetry, Chronoamperometry, Electrochemical impedance spectroscopy
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-143882 (URN)10.1016/j.jelechem.2017.12.072 (DOI)000445054900014 ()
Funder
Sida - Swedish International Development Cooperation Agency
Available from: 2018-01-12 Created: 2018-01-12 Last updated: 2018-10-30Bibliographically approved
Meynaq, M. Y., Lindholm-Sethson, B. & Tesfalidet, S. (2018). Interaction of anions with lipid cubic phase membranes, an electrochemical impedance study. Journal of Colloid and Interface Science, 528, 263-270
Open this publication in new window or tab >>Interaction of anions with lipid cubic phase membranes, an electrochemical impedance study
2018 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 528, p. 263-270Article in journal (Refereed) Published
Abstract [en]

Hypothesis: Electrochemical impedance spectroscopy is useful to monitor anionic interactions with a Lipid Cubic Phase, as previously demonstrated for cationic interaction (Khani Meynaq et al., 2016). It was expected that the smaller hydrophilic anions, acetate and chloride, would interact differently than the large tryptophan anion with its hydrophobic tail.

Experiment: The impedance measurements enabled estimation of resistances and capacitances of a freestanding lipid cubic phase membrane at exposure to 4 and 40 mM solutions of NaCl, NaOAc and NaTrp. Small-angle X-ray scattering was used for cubic phase identification and to track structural changes within the cubic phase when exposed to the different electrolytes.

Findings: The membrane resistance increases at exposure to the electrolytes in the order Cl− < OAc− < Trp−. The membrane resistance decreases with time at exposure to the hydrophilic anions and increases with time at Trp− exposure. The membrane capacitances were lower for NaTrp compared to NaCl and NaOAc at the corresponding concentrations which is consistent with the results from SAXRD. It is concluded that Trp− ions do not enter the aqueous channels of the cubic phase but are strongly adsorbed to the membrane/electrolyte interface leading to large alteration of the lipid phase structure and a high membrane resistance.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Lipid cubic phase, Electrochemical impedance spectroscopy, Tryphtophan, Chloride, Acetate, Capacitance, Resistance, Anion, Ionic interaction, Small-angle X-ray diffraction
National Category
Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-148295 (URN)10.1016/j.jcis.2018.05.071 (DOI)000440127000028 ()
Available from: 2018-06-01 Created: 2018-06-01 Last updated: 2018-09-04Bibliographically approved
Aghbolagh, M. S., Meynaq, M. Y., Shimizu, K. & Lindholm-Sethson, B. (2017). Aspects on mediated glucose oxidation at a supported cubic phase. Bioelectrochemistry, 118, 8-13
Open this publication in new window or tab >>Aspects on mediated glucose oxidation at a supported cubic phase
2017 (English)In: Bioelectrochemistry, ISSN 1567-5394, E-ISSN 1878-562X, Vol. 118, p. 8-13Article in journal (Refereed) Published
Abstract [en]

A supported liquid crystalline cubic phase housing glucose oxidase on an electrode surface has been suggested as bio-anode in a biofuel. The purpose of this investigation is to clarify some aspect on the mediated enzymatic oxidation of glucose in such a bio-anode where the mediator ferrocene-carboxylic acid and glucose were dissolved in the solution. The enzyme glucose oxidase was housed in the water channels of the mono-olein cubic phase. The system was investigated with cyclic voltammetry at different scan rates and the temperature was varied between 15 degrees C and 30 degrees C. The diffusion coefficient of the mediator and also the film resistance was estimated showing a large decrease in the mass-transport properties as the temperature was decreased. The current from mediated oxidation of glucose at the electrode surface increased with decreasing film thickness. The transport of the mediator in the cubic phase was the rate-limiting step in the overall reaction, where the oxidation of glucose took place at the outer surface of the cubic phase.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Enzymatic biofuel cells, Lipid cubic phase, Liquid-crystal, Monoolein, Glucose oxidase, Ferrocene-carboxylic acid
National Category
Materials Chemistry Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-130584 (URN)10.1016/j.bioelechem.2017.06.010 (DOI)000412258800002 ()28672274 (PubMedID)
Note

Originally included in thesis in manuscript form.

Available from: 2017-01-24 Created: 2017-01-24 Last updated: 2018-06-09Bibliographically approved
Krupinska, K., Geladi, P., Vikholm-Lundin, I. & Lindholm-Sethson, B. (2017). Detection of low levels of Escherichia coli by electrochemical impedance spectroscopy and singular value decomposition. Chemometrics and Intelligent Laboratory Systems, 163, 49-54
Open this publication in new window or tab >>Detection of low levels of Escherichia coli by electrochemical impedance spectroscopy and singular value decomposition
2017 (English)In: Chemometrics and Intelligent Laboratory Systems, ISSN 0169-7439, E-ISSN 1873-3239, Vol. 163, p. 49-54Article in journal (Refereed) Published
Abstract [en]

The first steps are reported in the development of a new ultrasensitive electrochemical biosensor for detection of Escherichia coli (E. coli) in water. Two gold electrodes in a sandwich flow-cell were modified with E. coli polyclonal antibody and exposed to three different concentrations of E. coli. Electrochemical Impedance Spectroscopy was used in combination with Singular Value Decompostion of the complex numbers to monitor the interactions at the electrode surfaces. A linear regression line in the concentration range 10-1000 CFU⁎ml-1 was obtained without use of redox probes or metal nanoparticles for signal amplification.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-128935 (URN)10.1016/j.chemolab.2016.11.008 (DOI)000399857600007 ()
Available from: 2016-12-20 Created: 2016-12-20 Last updated: 2018-06-09Bibliographically approved
Phal, S., Lindholm-Sethson, B., Geladi, P., Shchukarev, A. & Tesfalidet, S. (2017). Determination of methotrexate in spiked human blood serum using multi-frequency electrochemical immittance spectroscopy and multivariate data analysis. Analytica Chimica Acta, 987, 15-24
Open this publication in new window or tab >>Determination of methotrexate in spiked human blood serum using multi-frequency electrochemical immittance spectroscopy and multivariate data analysis
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2017 (English)In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 987, p. 15-24Article in journal (Refereed) Published
Abstract [en]

This article describes an attempt to develop a sensor based on multi-frequency immittance spectroscopy for the determination of methotrexate (MTX) in blood serum using gold electrodes modified with antibodies. The attachment of antibodies was monitored with electrochemical immittance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The EIS measurements of MTX resulted in a data matrix of size 39 × 55. The data were analysed using multivariate data analysis and showed a concentration dependence and time dependence that could be separated. This allowed the calculation of a multivariate calibration model. The model showed good linear behavior on a logarithmic scale offering a detection limit of 5 × 10−12 mol L−1.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Gold electrode, Biosensor, X-ray photoelectron spectroscopy, Singular value decomposition, Multivariate calibration model, Antibody
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-138962 (URN)10.1016/j.aca.2017.08.034 (DOI)000410304700002 ()28916036 (PubMedID)
Available from: 2017-09-05 Created: 2017-09-05 Last updated: 2018-06-09Bibliographically approved
Tesfalidet, S., Geladi, P., Shimizu, K. & Lindholm-Sethson, B. (2016). Detection of methotrexate in a flow system using electrochemical impedance spectroscopy and multivariate data analysis. Analytica Chimica Acta, 914, 1-6
Open this publication in new window or tab >>Detection of methotrexate in a flow system using electrochemical impedance spectroscopy and multivariate data analysis
2016 (English)In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 914, p. 1-6Article in journal (Refereed) Published
Abstract [en]

Abstract Methotrexate (MTX), a common pharmaceutical drug in cancer therapy and treatment of rheumatic diseases, is known to cause severe adverse side effects at high dose. As the side effect may be life threatening, there is an urgent need for a continuous, bed-side monitoring of the nominal MTX serum level in a patient while the chemical is being administered. This article describes a detection of MTX using a flow system that consists two modified gold electrodes. Interaction of MTX with the antibodies fixed on the electrode surface is detected by electrochemical impedance spectroscopy and evaluated using singular value decomposition (SVD). The key finding of this work is that the change in the electrode capacitance is found to be quantitative with respect to the concentration of MTX. Moreover a calibration curve constructed using the principal component regression method has a linear range of six orders of magnitude and a detection limit of 1.65 × 10−10 M.

Keywords
Methotrexate, Impedance spectrometry, Flow cell, Complex number singular value decomposition, Gold electrode, Calibration model
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-117445 (URN)10.1016/j.aca.2016.02.012 (DOI)000371348100001 ()26965322 (PubMedID)
Available from: 2016-02-29 Created: 2016-02-29 Last updated: 2018-06-07Bibliographically approved
Khani Meynaq, M. Y., Shimizu, K., Aghbolagh, M. S., Tesfalidet, S. & Lindholm-Sethson, B. (2016). Investigation of metal ion interaction with a lipid cubic phase using electrochemical impedance spectroscopy. Journal of Colloid and Interface Science, 482, 212-220
Open this publication in new window or tab >>Investigation of metal ion interaction with a lipid cubic phase using electrochemical impedance spectroscopy
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2016 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 482, p. 212-220Article in journal (Refereed) Published
Abstract [en]

AbstractHypothesis Electrochemical impedance spectroscopy, EIS, can be used as a complementary technique to investigate ion interaction with the headgroup region in the aqueous channels of a lipid cubic phase, LCP. Experiments A freestanding membrane made of monoolein LCP was formed by filling a small aperture that separates two cell compartments. The cell compartments were filled with electrolyte solutions at two different ionic strengths: i.e.: 10 and 100 mM, of KCl, CsBr and CaCl2. Electrochemical impedance spectroscopy was recorded between two platinum electrodes that were present at each side of the membrane. Findings The membrane resistance and capacitance were estimated from equivalent circuit fitting of the impedance data. It was confirmed that calcium ions interacts strongly with the headgroup region in the aqueous channels giving significantly higher membrane resistances compared to monovalent alkali metal ions. The membrane capacitance with Ca2+(aq) in solution was concentration dependent, which for the first time indicates formation of two different cubic phases at these conditions.

Keywords
Lipid cubic phase, Electrochemical impedance spectroscopy, Monoolein, Lipid–ion interactions, Calcium, Cesium, Potassium, Ionic permeability, Membrane resistance, Membrane capacitance
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-124993 (URN)10.1016/j.jcis.2016.07.053 (DOI)000383305700025 ()27505274 (PubMedID)
Available from: 2016-09-01 Created: 2016-09-01 Last updated: 2018-06-07Bibliographically approved
Shimizu, K., Nyström, J., Geladi, P., Lindholm-Sethson, B. & Boily, J.-F. (2015). Electrolyte ion adsorption and charge blocking effect at the hematite/aqueous solution interface: an electrochemical impedance study using multivariate data analysis. Physical Chemistry, Chemical Physics - PCCP, 17(17), 11560-11568
Open this publication in new window or tab >>Electrolyte ion adsorption and charge blocking effect at the hematite/aqueous solution interface: an electrochemical impedance study using multivariate data analysis
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2015 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 17, no 17, p. 11560-11568Article in journal (Refereed) Published
Abstract [en]

A model-free multivariate analysis using singular value decomposition is employed to refine an equivalent electrical circuit model in order to probe the electrochemical properties of the hematite/water interface in dilute NaCl and NH4Cl solutions using electrochemical impedance spectroscopy. The result shows that the surface protonation is directly related to the mobility and trapping of charge carriers at the mineral surface. Moreover, the point of zero charge can be found at pH where the charge transfer resistance is the highest, in addition to the minimum double layer capacitance. The innersphere interaction of the NH4+ ion with the surface is indicated by an increase of capacitance for charge carrier trapping from the protonated surface as well as lower double layer capacitance and open circuit potential. It is clear that the intrinsic electrochemical activity of hematite depends on the degree of surface (de) protonation and other inner-sphere adsorption, as these processes affect the charge carrier density in the surface state. This work also highlights an important synergistic effect of the two spectral analyses that enables EIS to be utilized in an in-depth investigation of mineral/water interfaces.

National Category
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-103230 (URN)10.1039/c4cp05927a (DOI)000353338800051 ()25857599 (PubMedID)
Available from: 2015-05-19 Created: 2015-05-18 Last updated: 2018-06-07Bibliographically approved
Hägerlind, E., Falk, M., Löfstedt, T., Lindholm-Sethson, B. & Bodén, I. (2015). Near infrared and skin impedance spectroscopy: a possible support in the diagnostic process of skin tumours in primary health care. Skin research and technology, 21(4), 493-499
Open this publication in new window or tab >>Near infrared and skin impedance spectroscopy: a possible support in the diagnostic process of skin tumours in primary health care
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2015 (English)In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 21, no 4, p. 493-499Article in journal (Refereed) Published
Abstract [en]

Background/purpose: The global incidence of skin cancer has increased drastically in recent decades, especially in Australia and Northern Europe. Early detection is crucial for good prognosis and high survival rates. In general, primary care physicians have considerably lower sensitivity and specificity rates for detection of skin cancer, compared to dermatologists. A probable main reason for this is that current diagnostic tools are subjective in nature, and therefore diagnostic skills highly depend on experience. Illustratively, in Sweden, approximately 155500 benign skin lesions are excised unnecessarily every year. An objective instrument, added to the clinical examination, might improve the diagnostic accuracy, and thus promote earlier detection of malignant skin tumours, as well as reduce medical costs associated with unnecessary biopsies and excisions. The general aim of this study was to investigate the usefulness of the combination of near infrared (NIR) and skin impedance spectroscopy as a supportive tool in the diagnosis and evaluation of skin tumours in primary health care. Methods: Near infrared and skin impedance data were collected by performing measurements on suspect malignant, premalignant and benign tumours in the skin of patients seeking primary health care for skin tumour evaluation. The obtained data were analysed using multivariate analysis and compared with the diagnosis received by the conventional diagnostic process. Results: The observed sensitivity and specificity rates were both 100%, when discriminating malignant and premalignant skin tumours from benign skin tumours, and the observed sensitivity and specificity for separating malignant skin tumours from premalignant and benign skin tumours were also 100%, respectively. Conclusion: The results of this study indicate that the NIR and skin impedance spectroscopy may be a useful supportive tool for the general practitioner in the diagnosis and evaluation of skin tumours in primary health care, as a complement to the visual assessment.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2015
Keywords
skin cancer diagnosis, early detection, diagnostic tool, primary care
National Category
Cancer and Oncology Dermatology and Venereal Diseases
Identifiers
urn:nbn:se:umu:diva-111140 (URN)10.1111/srt.12219 (DOI)000362679600014 ()25773339 (PubMedID)
Available from: 2015-11-12 Created: 2015-11-06 Last updated: 2018-06-07Bibliographically approved
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