uu.seUppsala University Publications
Change search
Refine search result
1 - 16 of 16
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Oldest first
  • Newest first
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 1.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Bergström Lind, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Influence of surface modification and static pressure on microdialysis protein extraction efficiency2015In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 17, no 5, UNSP 96Article in journal (Refereed)
    Abstract [en]

    There is growing interest in using microdialysis (MD) for monitoring larger and more complexmolecules such as neuropeptides and proteins. This promotes the use of MD membranes withmolecular weight cut off (MWCO) of 100 kDa or above. The hydrodynamic property of themembrane goes to ultrafiltration or beyond, making the MD catheters more sensitive to pressure.In the meantime, despite the large pore size, studies have shown that membrane biofouling stilllead to unstable catheter performance. The objective is to study in vitro how 500 kDa dextranand Poloxamer 407 surface modification affect the fluid recovery (FR) and extraction efficiency(EE) of 100 kDa MWCO MD catheters. A pressure chamber was designed to facilitate the tests,using as MD sample a protein standard with similar concentrations as in human cerebral spinalfluid, comparing native and Poloxamer 407 modified MD catheters. The collected dialysatefractions were examined for FR and protein EE, employing Dot-it Spot-it Protein Assay for totalprotein EE and targeted mass spectrometry (MS) for EE of individual proteins and peptides. TheFR results suggested that the surface modified catheters were less sensitive to the pressure andprovide higher precision, and provided a FR closer to 100%. The surface modification did notshow a significant effect on the protein EE. The average total protein EE of surface modifiedcatheters was slightly higher than that of the native ones. The MS EE data of individual proteinsshowed a clear trend of complex response in EE with pressure.

  • 2.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wang, Cong
    Park, Jungyul
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Protein Desalination Chip for Mass Spectrometry Sample Preparation2015Conference paper (Refereed)
    Abstract [en]

    This work focuses on desalination of a protein sample in a lab-on-chip device using the ion concentration polarization (ICP) technique. It was demonstrated with a salt containing buffer with four proteins and two peptides of concentrations typical to cerebrospinal fluid (CSF). Not only was the output desalinated but its protein concentration with large molecular weight (MW) was as much as 3 times higher for the largest protein compared to the original. We conclude that ICP based microfluidic chips have great potential for desalination and protein concentration in microdialysis sampling coupled to mass spectroscopy (MS).

  • 3.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Lind, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Influence of different pluronic surface modifications and pressure on microdialysis protein extraction efficiency2015In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781Article in journal (Refereed)
    Abstract [en]

    There is growing interest in using microdialysis (MD) for monitoring larger and more complexmolecules such as neuropeptides and proteins. This promotes the use of MD membranes withmolecular weight cut off (MWCO) of 100 kDa. Hence, the hydrodynamic property of themembrane goes to ultrafiltration, making the sampling more sensitive to pressure changes. Also,despite the large membrane pore size, studies have shown that membrane biofouling still leads tounstable catheter performance. Our objective is to study in vitro how four kinds of surfacemodifications (Pluronic L31, L44, F87 and F127+L31) affect the fluid recovery (FR) andextraction efficiency (EE) of 100 kDa MWCO MD catheters, under controlled pressure. Apressure chamber was employed to facilitate the tests, using as MD sample a protein standardwith proteins of similar concentrations as in human cerebral spinal fluid. The collected dialysatefractions were examined for FR and EE. Targeted mass spectrometry analysed the EE ofindividual proteins and peptides. The thicker the pluronic adsorption layer, the less thehydrodynamic diameter of the membrane pores, leading to lower and more stable FR. The foursurface modifications had three different behaviours: Pluronic F127 + L31 showed similarbehavior to the Pluronic F127 and the native original membrane; Pluronic F87 showed acontinuous EE increase with pressure; Pluronic L31 and L44 showed similar EE values, whichwere stable with pressure. Different surface modifications are clearly selective to differentproteins and peptides. We conclude that a pluronic surface modification could provide MDsampling with more stable FR, and more stable or enhanced EE with high FR, depending on theobjective of the sampling.

  • 4.
    Enmark, Martin
    et al.
    Department of Chemistry and Biomedical Sciences, Karlstad University, Sweden.
    Samuelsson, Jörgen
    Department of Chemistry and Biomedical Sciences, Karlstad University, Sweden.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Fornstedt, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Characterization of an unusual adsorption behavior of racemic methyl-mandelate on a tris-(3,5-dimethylphenyl) carbamoyl cellulose chiral stationary phase2011In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1218, no 38, 6688-6696 p.Article in journal (Refereed)
    Abstract [en]

    An interesting adsorption behavior of racemic methyl mandelate on a tris-(3,5-dimethylphenyl)carbamoyl cellulose chiral stationary phase was theoretically and experimentally investigated. The overloaded band of the more retained enantiomer had a peculiar shape indicating a type V adsorption isotherm whereas the overloaded band of the less retained enantiomer had a normal shape indicating a type I adsorption behavior. For a closer characterization of this separation, adsorption isotherms were determined and analyzed using an approach were Scatchard plots and adsorption energy distribution (AED) calculations are combined for a deeper analysis. It was found that the less retained enantiomer was best described by a Tóth adsorption isotherm while the second one was best described with a bi-Moreau adsorption isotherm. The latter model comprises non-ideal adsorbate–adsorbate interactions, providing an explanation to the non-ideal adsorption of the more retained enantiomer. Furthermore, the possibility of using the Moreau model as a local model for adsorption in AED calculations was evaluated using synthetically generated raw adsorption slope data. It was found that the AED accurately could predict the number of adsorption sites for the generated data. The adsorption behavior of both enantiomers was also studied at several different temperatures and found to be exothermic; i.e. the adsorbate–adsorbate interaction strength decreases with increasing temperature. Stochastic analysis of the adsorption process revealed that the average amount of adsorption/desorption events increases and the sojourn time decreases with increasing temperature.

  • 5.
    Samuelsson, Jörgen
    et al.
    Department of Chemistry and Biomedical Sciences, Karlstad University, Sweden.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Fornstedt, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Expanding the elution by characteristic point method for determination of various types of adsorption isotherms2011In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1218, no 24, 3737-3742 p.Article in journal (Refereed)
    Abstract [en]

    Important improvements have recently been made on the elution by characteristic point (ECP) method to increase the accuracy of the determined adsorption isotherms. However, the method has so far been limited/used for only type I adsorption isotherms (e.g. Langmuir, Toth, bi-Langmuir). In this study, general strategies are developed to expand the ECP method for the determination of more complex adsorption isotherms including such containing inflection points. We will exemplify the methodology with type II, type III and type V isotherms. Guidelines are given for how to determine such isotherms using the ECP method and for the experimental considerations that must be taken into account or that may be eliminated in the particular case.

  • 6.
    Samuelsson, Jörgen
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Törncrona, Anders
    Eka Chemicals AB, Separation Products,Sweden.
    Fornstedt, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Improvement in the generation of adsorption isotherm data in the elution by characteristic points method: the ECP-slope approach.2010In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1217, no 46, 7215-7221 p.Article in journal (Refereed)
    Abstract [en]

    The elution by characteristic points (ECP) method is a very rapid and precise method for determination of the phase system equilibrium of phase systems in broad solute concentration ranges. Thus, the method is especially suitable for rapid characterization of high efficient separation systems. One important source of error, the effects by the post-loop dispersion, was eliminated in a recent investigation. In this study, the systematic error caused by the selection of the integration starting point at concentration equal to 0 is eliminated. This is done by developing and validating a new procedure for isotherm data generation; the ECP-slope method. The method generates raw slope data of the adsorption isotherm instead of raw adsorption data by integrations as the classical ECP does. Both numerical and experimental data were used for the comparison of the classical ECP approach with the slope-ECP method.

  • 7.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Development and improvement of methods for characterization of HPLC stationary phases2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    High Performance Liquid Chromatography (HPLC) is a widely used tech-nique both for detecting and purifying substances in academy and in the industry. In order to facilitate the use of, and knowledge in HPLC, character-ization of stationary phases is of utmost importance. Tailor made characteri-zation methods and workflows are steadily increasing the speed and accura-cy in which new separation systems and methods are developed. In the field fundamental separation science and of preparative chromatography there is always the need for faster and more accurate methods of adsorption isotherm determination. Some of that demand are met with the steadily increase of computational power, but the practical aspects on models and methods must also be further developed. These nonlinear characterization methods will not only give models capable of describing the adsorption isotherm but also actual values of local adsorption energies and monolayer saturation capacity of an individual interaction sites etc.The studies presented in this thesis use modern alkali stable stationary phas-es as a model phase, which will give an insight in hybrid materials and their separation mechanism. This thesis will include an update and expansion in using the Elution by Characteristic Points (ECP) method for determination of adsorption isotherms. The precision is even further increased due to the ability to use slope data as well as an increase in usability by assigning a set of guidance rules to be applied when determine adsorption isotherms having inflection points. This thesis will further provide the reader with information about stationary phase characterization and the power of using existing tech-niques; combine them with each other, and also what the expansion of meth-ods can revile in terms of precision and increased usability. A more holistic view of what benefits that comes with combining a non-linear characteriza-tion of a stationary phase with more common linear characterization meth-ods are presented.

    List of papers
    1. Improvement in the generation of adsorption isotherm data in the elution by characteristic points method: the ECP-slope approach.
    Open this publication in new window or tab >>Improvement in the generation of adsorption isotherm data in the elution by characteristic points method: the ECP-slope approach.
    2010 (English)In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1217, no 46, 7215-7221 p.Article in journal (Refereed) Published
    Abstract [en]

    The elution by characteristic points (ECP) method is a very rapid and precise method for determination of the phase system equilibrium of phase systems in broad solute concentration ranges. Thus, the method is especially suitable for rapid characterization of high efficient separation systems. One important source of error, the effects by the post-loop dispersion, was eliminated in a recent investigation. In this study, the systematic error caused by the selection of the integration starting point at concentration equal to 0 is eliminated. This is done by developing and validating a new procedure for isotherm data generation; the ECP-slope method. The method generates raw slope data of the adsorption isotherm instead of raw adsorption data by integrations as the classical ECP does. Both numerical and experimental data were used for the comparison of the classical ECP approach with the slope-ECP method.

    Keyword
    Single component adsorption, Adsorption isotherms, Elution by characteristic points method, Slope data, The ECP-slope method
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-161211 (URN)10.1016/j.chroma.2010.09.004 (DOI)000284439800005 ()
    Available from: 2011-11-09 Created: 2011-11-09 Last updated: 2015-05-12Bibliographically approved
    2. Expanding the elution by characteristic point method for determination of various types of adsorption isotherms
    Open this publication in new window or tab >>Expanding the elution by characteristic point method for determination of various types of adsorption isotherms
    2011 (English)In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1218, no 24, 3737-3742 p.Article in journal (Refereed) Published
    Abstract [en]

    Important improvements have recently been made on the elution by characteristic point (ECP) method to increase the accuracy of the determined adsorption isotherms. However, the method has so far been limited/used for only type I adsorption isotherms (e.g. Langmuir, Toth, bi-Langmuir). In this study, general strategies are developed to expand the ECP method for the determination of more complex adsorption isotherms including such containing inflection points. We will exemplify the methodology with type II, type III and type V isotherms. Guidelines are given for how to determine such isotherms using the ECP method and for the experimental considerations that must be taken into account or that may be eliminated in the particular case.

    Keyword
    Elution by characteristic points, Adsorption isotherms, Inflection points, Frontal analysis by characteristic points, Moreau isotherm, BET-isotherms
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-155586 (URN)10.1016/j.chroma.2011.04.035 (DOI)000291576400002 ()
    Available from: 2011-06-28 Created: 2011-06-27 Last updated: 2017-01-25Bibliographically approved
    3. Evaluation of a combined linear and nonlinear approach for characterization of adsorption processes in chromatographic systems using modern alkaline stable columns as model
    Open this publication in new window or tab >>Evaluation of a combined linear and nonlinear approach for characterization of adsorption processes in chromatographic systems using modern alkaline stable columns as model
    (English)Manuscript (preprint) (Other academic)
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-166986 (URN)
    Available from: 2012-01-18 Created: 2012-01-18 Last updated: 2012-01-18
  • 8.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Characterization of Molecular Adsorption Using Liquid Chromatography and Mass Spectrometry2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Molecular adsorption is a key feature in several disciplines of chemistry, covering as diverse fields as chromatographic separation to biomaterial development. This thesis aims at developing methods and techniques for the characterization of molecular adsorption at the liquid-solid interface. Two different experimental models were used, small molecular interaction characterization using liquid chromatography and complex protein adsorption on polymeric materials possible for biological sampling. Holistic approaches, where both detailed molecular interactions and identifications of trends, could improve the fundamental understanding of adsorption systems, were invariably part of the scientific process.

    The characterization of small molecular interactions on liquid chromatography stationary phases via adsorption isotherm determination used combined data from physical phase parameters i.e. carbon loading, linear-, and nonlinear-characterization methods. These experiments were conducted on high performance liquid chromatography systems, using both ordinary reversed phase stationary phases, and hybrid phases. The expansion of the improved elusion by characteristic point (ECP) for adsorption isotherm determination, led to that previous impossible isotherm types, having inflexion points, now could be determined by the method. It also reduced errors in isotherm parameters due to the elimination of inaccurate determined retention times where the mobile phase concentration was zero.

    The characterization of protein adsorption where performed in an unbiased way. Adsorbed proteins on different surfaces were identified using mass spectrometry (MS) and data dependent acquisition or a targeted method. Prior MS, an improved on surface enzymatic digestion (oSED) method was used to enable identification and quantitation of adsorbed protein originating from ventricular cerebrospinal fluid (vCSF). oSED was found to be able to experimentally determine large variations in protein adsorption characteristics between native and coated polycarbonate surfaces in contact with vCSF. The method was also confirmed being mechanistic in favor of enzymatic digestion of the proteins adsorbed on a surface, rather than a prior desorption into solution before digestion.

    An improvement of the overall understanding of adsorption systems was not only achieved with the oSED method as a promising tool for characterization of protein adsorption on arbitrary surfaces, but also the use of linear and nonlinear approaches in stationary phase characterization that strengthened drawn conclusions.

    List of papers
    1. Improvement in the generation of adsorption isotherm data in the elution by characteristic points method: the ECP-slope approach.
    Open this publication in new window or tab >>Improvement in the generation of adsorption isotherm data in the elution by characteristic points method: the ECP-slope approach.
    2010 (English)In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1217, no 46, 7215-7221 p.Article in journal (Refereed) Published
    Abstract [en]

    The elution by characteristic points (ECP) method is a very rapid and precise method for determination of the phase system equilibrium of phase systems in broad solute concentration ranges. Thus, the method is especially suitable for rapid characterization of high efficient separation systems. One important source of error, the effects by the post-loop dispersion, was eliminated in a recent investigation. In this study, the systematic error caused by the selection of the integration starting point at concentration equal to 0 is eliminated. This is done by developing and validating a new procedure for isotherm data generation; the ECP-slope method. The method generates raw slope data of the adsorption isotherm instead of raw adsorption data by integrations as the classical ECP does. Both numerical and experimental data were used for the comparison of the classical ECP approach with the slope-ECP method.

    Keyword
    Single component adsorption, Adsorption isotherms, Elution by characteristic points method, Slope data, The ECP-slope method
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-161211 (URN)10.1016/j.chroma.2010.09.004 (DOI)000284439800005 ()
    Available from: 2011-11-09 Created: 2011-11-09 Last updated: 2015-05-12Bibliographically approved
    2. Expanding the elution by characteristic point method for determination of various types of adsorption isotherms
    Open this publication in new window or tab >>Expanding the elution by characteristic point method for determination of various types of adsorption isotherms
    2011 (English)In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1218, no 24, 3737-3742 p.Article in journal (Refereed) Published
    Abstract [en]

    Important improvements have recently been made on the elution by characteristic point (ECP) method to increase the accuracy of the determined adsorption isotherms. However, the method has so far been limited/used for only type I adsorption isotherms (e.g. Langmuir, Toth, bi-Langmuir). In this study, general strategies are developed to expand the ECP method for the determination of more complex adsorption isotherms including such containing inflection points. We will exemplify the methodology with type II, type III and type V isotherms. Guidelines are given for how to determine such isotherms using the ECP method and for the experimental considerations that must be taken into account or that may be eliminated in the particular case.

    Keyword
    Elution by characteristic points, Adsorption isotherms, Inflection points, Frontal analysis by characteristic points, Moreau isotherm, BET-isotherms
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-155586 (URN)10.1016/j.chroma.2011.04.035 (DOI)000291576400002 ()
    Available from: 2011-06-28 Created: 2011-06-27 Last updated: 2017-01-25Bibliographically approved
    3. Evaluation of a combined linear–nonlinear approach for column characterization using modern alkaline-stable columns as model
    Open this publication in new window or tab >>Evaluation of a combined linear–nonlinear approach for column characterization using modern alkaline-stable columns as model
    2013 (English)In: Journal of Separation Science, ISSN 1615-9306, E-ISSN 1615-9314, Vol. 36, no 11, 1753-1761 p.Article in journal (Refereed) Published
    Abstract [en]

    This study investigates if deeper understanding is achieved when combining nonlinear and linear chromatographic column characterization methods. As test systems, two hybrid columns (Phenomenex Gemini-NX C18 and Kromasil Eternity C18) and one classic one (Kromasil-C18) were selected. The nonlinear methods were based on firm adsorption theory and involved determination of adsorption isotherms followed by calculations with a new numerical tool, adsorption energy distribution, on probe components at different pH values. The linear methods involved the hydrophobic subtraction model and selected probe components retention factors as a function of pH. The combined analysis indicated that both complementary and confirmative information can be achieved regarding the actual model systems.

    Keyword
    Adsorption isotherms, Characterization, Linear methods, Nonlinear methods, Retention
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-202052 (URN)10.1002/jssc.201201132 (DOI)000319919900009 ()
    Available from: 2013-06-19 Created: 2013-06-19 Last updated: 2015-05-12Bibliographically approved
    4. A mass spectrometry based method for investigating time dependent protein adsorption on surfaces in contact with complex biological samples
    Open this publication in new window or tab >>A mass spectrometry based method for investigating time dependent protein adsorption on surfaces in contact with complex biological samples
    (English)Article in journal (Other academic) Submitted
    Keyword
    time-resolved, protein adsorption, mass spectrometry, on-surface digestion, oSED, ventricular cerebrospinal fluid, polycarbonate membrane, Bottom-up, Shotgun, vCSF, Peptides
    National Category
    Analytical Chemistry
    Research subject
    Chemistry with specialization in Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-248998 (URN)
    Funder
    Magnus Bergvall FoundationBerzelii Centre EXSELENTÅke Wiberg Foundation
    Available from: 2015-04-09 Created: 2015-04-09 Last updated: 2017-01-24
    5. Mass spectrometric determination of the effect of surface deactivation on membranes used for the sampling of cerebrospinal fluid (CSF)
    Open this publication in new window or tab >>Mass spectrometric determination of the effect of surface deactivation on membranes used for the sampling of cerebrospinal fluid (CSF)
    (English)Manuscript (preprint) (Other academic)
    Keyword
    Protein Adsorption, Mass Spectrometry, oSED, Surface modification, Coating, Poloxamer 407, Pluronic F127, Trypsin, Digestion, Shotgun, Bottom-up, peptides
    National Category
    Analytical Chemistry
    Research subject
    Chemistry with specialization in Analytical Chemistry; Chemistry with specialization in Surface Biotechnology
    Identifiers
    urn:nbn:se:uu:diva-248631 (URN)
    Funder
    Magnus Bergvall FoundationÅke Wiberg FoundationSwedish Research Council for Environment, Agricultural Sciences and Spatial Planning, 621-2011-4423Berzelii Centre EXSELENT
    Available from: 2015-04-05 Created: 2015-04-05 Last updated: 2017-01-24
    6. Mechanistic investigation of the on surface enzymatic digestion (oSED) protein adsorption detection method using targeted mass spectrometry
    Open this publication in new window or tab >>Mechanistic investigation of the on surface enzymatic digestion (oSED) protein adsorption detection method using targeted mass spectrometry
    Show others...
    2016 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 141, no 5, 1714-1720 p.Article in journal (Refereed) Published
    Abstract [en]

    This study describes our efforts to study some of the mechanistic aspects of the earlier established onsurface enzymatic digestion (oSED) method. In a multitude of application areas, it has become important to be able to fully characterize and understand selective protein adsorption to biomaterial surfaces for various applications, including biomedicine (implants), nanotechnology (microchip surfaces and sensors) and materials sciences. Herein, the investigation of the mechanistic aspects was based on microdialysis catheter tubes that were flushed with controlled protein solutions mimicking the extracellular fluid of the brain. The protein adsorption properties were monitored using high-resolution liquid chromatography tandem mass spectrometry (LC-MS/MS) with a targeted method. The temporally resolved results show that most proteins stay adsorbed onto the surface during the entire digestion process and are only cut away piece by piece, whereas smaller proteins and peptides seem to desorb rather easily from the surface. This information will simplify the interpretation of data generated using the oSED method and can also be used for the characterization of the physicochemical properties controlling the adsorption of individual proteins to specific surfaces.

    National Category
    Analytical Chemistry Engineering and Technology
    Research subject
    Chemistry with specialization in Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-248629 (URN)10.1039/c5an02091c (DOI)000371229600018 ()
    Funder
    Magnus Bergvall FoundationBerzelii Centre EXSELENTSwedish Research Council, 621-2011-4423
    Available from: 2015-04-05 Created: 2015-04-05 Last updated: 2017-01-24Bibliographically approved
  • 9.
    Undin, Torgny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wetterhall, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Competitive Protein Adsorption as Observed and Quantified by - Surface Enzymatic Digestion (oSED) and Mass Spectrometry2012In: 60th ASMS Conference on Mass Spectrometry and Allied Topics, May 20 - 24, Vancouver, Canada, 2012Conference paper (Refereed)
  • 10.
    Undin, Torgny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Bergström Lind, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Bergquist, Jonas
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Mass spectrometric determination of the effect of surface deactivation on membranes used for the sampling of cerebrospinal fluid (CSF)Manuscript (preprint) (Other academic)
  • 11.
    Undin, Torgny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Bergström Lind, Sara
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A mass spectrometry based method for investigating time dependent protein adsorption on surfaces in contact with complex biological samplesArticle in journal (Other academic)
  • 12.
    Undin, Torgny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Bergström Lind, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    MS for investigation of time-dependent protein adsorption on surfaces in complex biological samples2015In: Future Science OA, ISSN 2056-5623, 32Article in journal (Refereed)
    Abstract [en]

    Aim: This study aims at developing a nondestructive way for investigating proteinadsorption on surfaces such as biomaterials using mass spectrometry. Methods: Ventricular cerebrospinal fluid in contact with poly carbonate membranes were usedas adsorption templates and on-surface enzymatic digestion was applied to desorbproteins and cleave them into peptides. Mass spectrometric analysis provided bothprotein identification and determination of protein specific adsorption behavior. Results: In general, the adsorption increased with incubation time but also proteinspecifictime-resolved adsorption patterns from the complex protein solutionwere discovered. Conclusion: The method developed is a promising tool for thecharacterization of biofouling, which sometimes causes rejection and encapsulationof implants and can be used as complement to other surface analytical techniques.

    One problem associated with artificial materials in the body is that proteins in thebody interact with the surface, which sometimes causes rejection of the implant.In this study, a method for investigating the time-dependent protein adsorptionon a surface originating from a complex biological protein solution was developed.Compared with other surface analyses, this method can identify what proteins thatadsorbs on the surface. In addition, determination of protein-specific adsorptionbehavior in relation to incubation was possible

  • 13.
    Undin, Torgny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Wetterhall, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Investigation of Time Dependent Competitive Protein Adsorption to Surfaces Using Mass Spectrometry2013Conference paper (Refereed)
    Abstract [en]

    Introduction

    Surfaces in a complex protein solution will adsorb proteins. This event is fast and dynamic and triggers a biological response against the inserted/implanted biomaterial that eventually will lead to biofouling and encapsulation. This affects the properties of the inserted devices, such as hampered membrane functions of microdialysis (MD) probes or distortion in response of biosensors.

    Methods

    Untreated and coated filtration membranes were used as adsorption templates for human ventricular cerebrospinal fluid (vCSF). After adsorption in an incubation chamber, the membranes were washed, dried and the proteins were reduced, alkylated and digested. The sample preparation procedure was conducted according to an on-surface enzymatic digestion (oSED) protocol previously described by our group. The oSED digests were analyzed by nanoLC ESI-MS/MS using a 7T hybrid LTQ FT and Velos pro orbitrap mass spectrometer.

    Preliminary Data

    In this study, we present a time resolved map of protein adsorption. Non-coated and tri-block polymer coated, polycarbonate membranes was used as templates. As expected, a time and surface property dependent protein adsorption relationship was observed. It is not surprising that the degree of protein binding onto modified and non-modified surfaces was dependent on the properties of the protein as well as the properties of the surface. The process of biofouling for in vivo inserted materials can be postponed and thereby increasing the lifetime and use of e.g. microdialysis probes for patient monitoring. The preliminary data are very promising making it possible to identify a spectra of adsorbed proteins on different surfaces in a time dependent way

  • 14.
    Undin, Torgny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hörnaeus, Katarina
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Bergström Lind, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Mechanistic investigation of the on surface enzymatic digestion (oSED) protein adsorption detection method using targeted mass spectrometry2016In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 141, no 5, 1714-1720 p.Article in journal (Refereed)
    Abstract [en]

    This study describes our efforts to study some of the mechanistic aspects of the earlier established onsurface enzymatic digestion (oSED) method. In a multitude of application areas, it has become important to be able to fully characterize and understand selective protein adsorption to biomaterial surfaces for various applications, including biomedicine (implants), nanotechnology (microchip surfaces and sensors) and materials sciences. Herein, the investigation of the mechanistic aspects was based on microdialysis catheter tubes that were flushed with controlled protein solutions mimicking the extracellular fluid of the brain. The protein adsorption properties were monitored using high-resolution liquid chromatography tandem mass spectrometry (LC-MS/MS) with a targeted method. The temporally resolved results show that most proteins stay adsorbed onto the surface during the entire digestion process and are only cut away piece by piece, whereas smaller proteins and peptides seem to desorb rather easily from the surface. This information will simplify the interpretation of data generated using the oSED method and can also be used for the characterization of the physicochemical properties controlling the adsorption of individual proteins to specific surfaces.

  • 15.
    Undin, Torgny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Samuelsson, J
    Törncrona, A
    Fornstedt, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Evaluation of a combined linear and nonlinear approach for characterization of adsorption processes in chromatographic systems using modern alkaline stable columns as modelManuscript (preprint) (Other academic)
  • 16.
    Undin, Torgny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Samuelsson, Jörgen
    Department of Engineering and Chemical Sciences, Karlstad University, Karlstad, Sweden.
    Törncrona, Anders
    AkzoNobel Pulp & Performance Chemicals AB, Bohus, Sweden.
    Fornstedt, Torgny
    Department of Engineering and Chemical Sciences, Karlstad University, Karlstad, Sweden.
    Evaluation of a combined linear–nonlinear approach for column characterization using modern alkaline-stable columns as model2013In: Journal of Separation Science, ISSN 1615-9306, E-ISSN 1615-9314, Vol. 36, no 11, 1753-1761 p.Article in journal (Refereed)
    Abstract [en]

    This study investigates if deeper understanding is achieved when combining nonlinear and linear chromatographic column characterization methods. As test systems, two hybrid columns (Phenomenex Gemini-NX C18 and Kromasil Eternity C18) and one classic one (Kromasil-C18) were selected. The nonlinear methods were based on firm adsorption theory and involved determination of adsorption isotherms followed by calculations with a new numerical tool, adsorption energy distribution, on probe components at different pH values. The linear methods involved the hydrophobic subtraction model and selected probe components retention factors as a function of pH. The combined analysis indicated that both complementary and confirmative information can be achieved regarding the actual model systems.

1 - 16 of 16
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf