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Caldwell, Karin
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Publications (10 of 12) Show all publications
Williams, S. K. & Caldwell, K. D. (2014). Field-flow fractionation. Analytical and Bioanalytical Chemistry, 406(6), 1577-1578
Open this publication in new window or tab >>Field-flow fractionation
2014 (English)In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 406, no 6, p. 1577-1578Article in journal, Editorial material (Other academic) Published
National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-222355 (URN)10.1007/s00216-013-7603-9 (DOI)000332317400001 ()
Available from: 2014-04-10 Created: 2014-04-10 Last updated: 2017-12-05Bibliographically approved
Dahlin, A. P., Wetterhall, M., Caldwell, K. D., Larsson, A., Bergquist, J., Hillered, L. & Hjort, K. (2010). Methodological aspects on microdialysis protein sampling and quantification in biological fluids: an in vitro study on human ventricular CSF.. Analytical Chemistry, 82(11), 4376-4385
Open this publication in new window or tab >>Methodological aspects on microdialysis protein sampling and quantification in biological fluids: an in vitro study on human ventricular CSF.
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2010 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 82, no 11, p. 4376-4385Article in journal (Refereed) Published
Abstract [en]

There is growing interest in sampling of protein biomarkers from the interstitial compartment of the brain and other organs using high molecular cutoff membrane microdialysis (MD) catheters. However, recent data suggest that protein sampling across such MD membranes is a highly complex process that needs to be further studied. Here, we report three major improvements for microdialysis sampling of proteins in complex biological matrixes. The improvements in this in vitro study using human ventricular cerebrospinal fluid as the sample matrix include increased fluid recovery control, decreased protein adsorption on the microdialysis membrane and materials, and novel quantitative mass spectrometry analysis. Dextrans in different concentrations and sizes were added to the perfusion fluid. It was found that dextrans with molecular mass 250 and 500 kDa provided a fluid recovery close to 100%. An improved fluid recovery precision could be obtained by self-assembly triblock polymer surface modification of the MD catheters. The modified catheters also delivered a significantly increased extraction efficiency for some of the investigated proteins. The final improvement was to analyze the dialysates with isobaric tagged (iTRAQ) proteomics, followed by tandem mass spectrometric analysis. By using this technique, 48 proteins could be quantified and analyzed with respect to their extraction efficiencies. The novel aspects of microdialysis protein sampling, detection, and quantification in biological fluids presented in this study should be considered as a first step toward better understanding and handling of the challenges associated with microdialysis sampling of proteins. The next step is to optimize the developed methodology in vivo.

National Category
Chemical Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-125676 (URN)10.1021/ac1007706 (DOI)000278062800014 ()20465223 (PubMedID)
Available from: 2010-05-26 Created: 2010-05-26 Last updated: 2017-12-12Bibliographically approved
Hansson, L.-O., Flodin, M., Nilsen, T., Caldwell, K., Fromell, K., Sunde, K. & Larsson, A. (2008). Comparison between Chicken and Rabbit Antibody Based Particle Enhanced Cystatin C Reagents for Immunoturbidimetry. Journal of immunoassay & immunochemistry, 29(1), 1-9
Open this publication in new window or tab >>Comparison between Chicken and Rabbit Antibody Based Particle Enhanced Cystatin C Reagents for Immunoturbidimetry
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2008 (English)In: Journal of immunoassay & immunochemistry, ISSN 1532-1819, E-ISSN 1532-4230, Vol. 29, no 1, p. 1-9Article in journal (Refereed) Published
Abstract [en]

We have compared three commercial particle enhanced cystatin C reagents. One of the reagents utilizes chicken antibodies and the other two reagents are rabbit antibody based. We show that the chicken antibody based reagent yields a higher delta absorbance when reacting with the antigen. IgY coupled to latex particles show a strong scatter response even at high antigen concentrations in contrast to the steep decline in scatter previously reported for IgY antibodies in solution. The reagent also showed a low CV for duplicate samples. Laying hens thus seems as an interesting source of antibodies for particle-enhanced immunoassays.

Keywords
Chicken antibodies, IgY, Rabbit antibodies, Latex particles, Particle-enhanced immunoassays, Cystatin C
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-13980 (URN)10.1080/15321810701734644 (DOI)000252219300001 ()
Available from: 2008-01-28 Created: 2008-01-28 Last updated: 2017-12-11Bibliographically approved
Xue, B., Ersson, B., Porath, J. & Caldwell, K. (2006). Chromatographic and fluorometric study of interactions between thiophilic and hydrophobic ligands and tryptophan peptide homologues. Journal of Chromatography A, 1107(1-2), 46-51
Open this publication in new window or tab >>Chromatographic and fluorometric study of interactions between thiophilic and hydrophobic ligands and tryptophan peptide homologues
2006 (English)In: Journal of Chromatography A, Vol. 1107, no 1-2, p. 46-51Article in journal (Refereed) Published
Abstract [en]

The interactions of tryptophan and its peptide homologues with thiophilic ligands were studied in terms of their chromatographic retention and steady-state fluorescence under various conditions, and compared with non-polar structures typically regarded as pure hydrophobic ligands. The experimental results show that both non-polar and polar interactions are involved in what has been termed “thiophilic adsorption chromatography”.

Keywords
Thiophilic adsorption, Chromatography, Fluorescence, Tryptophan, Hydrophobic interaction
Identifiers
urn:nbn:se:uu:diva-76016 (URN)
Available from: 2007-02-13 Created: 2007-02-13 Last updated: 2011-01-11
Gullberg, E., Keita, Å. V., Salim, S. Y., Andersson, M., Caldwell, K. D., Söderholm, J. D. & Artursson, P. (2006). Identification of Cell Adhesion Molecules in the Human Follicle-Associated Epithelium That Improve Nanoparticle Uptake into the Peyer's Patches. Journal of Pharmacology and Experimental Therapeutics, 319(2), 632-639
Open this publication in new window or tab >>Identification of Cell Adhesion Molecules in the Human Follicle-Associated Epithelium That Improve Nanoparticle Uptake into the Peyer's Patches
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2006 (English)In: Journal of Pharmacology and Experimental Therapeutics, ISSN 0022-3565, E-ISSN 1521-0103, Vol. 319, no 2, p. 632-639Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to identify cell adhesion molecules that could serve as targets of the human follicle-associated epithelium (FAE) overlying Peyer's patches and to assess nanoparticle uptake levels across this epithelium. We first studied the expression of the mouse M-cell marker beta(1)-integrin and used a model of human FAE derived from intestinal epithelial Caco-2 cells and Raji B-cells to identify additional potential targets by cDNA array. The protein expression of potential targets in the model FAE and in human ileal FAE tissues was quantified by immunofluorescence. Integrin targeting was studied by investigating the transport of Arg-Gly-Asp (RGD)-coated (integrin- binding), Arg-Gly-Glu (RGE)-coated (nonintegrin-binding), and uncoated nanoparticles across ileal specimens mounted in Ussing chambers. Both beta(1)-integrin and the cell adhesion molecule CD9 were more abundantly expressed in the model and human FAE compared with the Caco-2 control cells or villus epithelium (VE). Uncoated nanoparticles were not taken up across either FAE or VE. General integrin targeting with RGD improved the nanoparticle transport dramatically across the FAE and to a lower extent across the VE. Compared with RGE, RGD improved transport 4-fold across the FAE. There was no difference in the transport of RGD- and RGE-coated nanoparticles across the VE. In conclusion, beta(1)-integrin and CD9 were identified as targets in human FAE. The difference in RGD- and RGE-mediated transport across the FAE, but not the VE, suggests that a specific integrin interaction was the dominating mechanism for improved nanoparticle uptake across the FAE., whereas charge interaction contributed substantially to the improved VE uptake.

National Category
Pharmaceutical Sciences
Identifiers
urn:nbn:se:uu:diva-83334 (URN)10.1124/jpet.106.107847 (DOI)000241403500014 ()16914557 (PubMedID)
Available from: 2007-02-13 Created: 2007-02-13 Last updated: 2018-01-13Bibliographically approved
Andersson, M., Fromell, K., Gullberg, E., Artursson, P. & Caldwell, K. (2005). Characterization of Surface-Modified Nanoparticles for in Vivo Biointeraction. A Sedimentation Field Flow Fractionation Study. Analytical Chemistry, 77, 5488-5493
Open this publication in new window or tab >>Characterization of Surface-Modified Nanoparticles for in Vivo Biointeraction. A Sedimentation Field Flow Fractionation Study
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2005 (English)In: Analytical Chemistry, Vol. 77, p. 5488-5493Article in journal (Refereed) Published
Abstract [en]

Sedimentation field flow fractionation (SdFFF) is an emerging high-performance analytical tool for separation and determination of size and adsorption characteristics of colloidal particles. This study demonstrates how SdFFF can be used to characterize nanoparticles prepared for in vivo applications including (1) the quantification of polymer uptake on nanoparticles where surface coverage is crucial and (2) the coupling of cell adhesive peptides containing the Arg-Gly-Asp motif (RGD). Quantitative information about polymer adhesion in order to prepare a bioinert surface and an accurate determination of ligand uptake are both of obvious importance for the understanding of, for example, relations between the number of attached molecules for biointeraction and an observed therapeutic effect. In addition, the present work highlights the necessity to perform careful characterization of commercially available particulate starting materials, in terms of size and polydispersity, prior to biological experimentation.

Keywords
FFF, nanoparticle, surface, modification, RGD, collodial, particles, analysis, quantification, polymer, uptake, surface, ligand, biotechnology
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-74523 (URN)
Available from: 2007-02-13 Created: 2007-02-13 Last updated: 2011-01-11
Caldwell, K. & Wahlund, K.-G. (2005). Field-Flow Fractionation in Protein Analysis. In: Methods for Structural Analysis of Protein Pharmaceuticals.
Open this publication in new window or tab >>Field-Flow Fractionation in Protein Analysis
2005 (English)In: Methods for Structural Analysis of Protein Pharmaceuticals, 2005Chapter in book (Refereed)
Identifiers
urn:nbn:se:uu:diva-70664 (URN)
Available from: 2007-02-13 Created: 2007-02-13
Fromell, K., Andersson, M., Elihn, K. & Caldwell, K. (2005). Nanoparticle decorated surfaces with potential use in glycosylation analysis. Colloids and Surfaces B: Biointerfaces, 46, 84–91
Open this publication in new window or tab >>Nanoparticle decorated surfaces with potential use in glycosylation analysis
2005 (English)In: Colloids and Surfaces B: Biointerfaces, Vol. 46, p. 84–91-Article in journal (Refereed) Published
Abstract [en]

A majority of all biologically active proteins are glycosylated and various diseases have proven to correlate with alterations in protein glycosylation. Sensitive identification of different glycoprotein glycoforms is therefore of great diagnostic value. Here we describe a method with potential for glycoprotein profiling, based on lectins as capture probes immobilized on particulate substrates in the nm-range. The nanoparticles present high concentrations of attachment sites for specific ligands and cause minimal steric hindrance to binding. In the present model study the mannose-binding lectin ConA has been coupled to polystyrene nanoparticles via a poly(ethyleneoxide) linker which protects the protein conformation and activity and prevents unspecific protein adsorption. The ConA-coated particles are accommodated at different spots on the analytical surface via oligonucleotide linkage. This attachment, which relies on the hybridization of complementary oligonucleotides, allows firm fixation of the particles at specific positions. The ConA attached to the particles has retained conformation and activity and binds selectively to a series of different glycoproteins. The results indicate the potential for using a multi-lectin nanoparticle array in glycoprotein mapping.

Keywords
Nanoparticles, Glycoprotein, Glycosylation
Identifiers
urn:nbn:se:uu:diva-25395 (URN)
Available from: 2007-02-12 Created: 2007-02-12 Last updated: 2011-01-12
ter Veen, R., Fromell, K. & Caldwell, K. (2005). Shifts in polystyrene particle surface charge upon adsorption of the Pluronic F108 surfactant. Journal of Colloid and Interface Science, 288(1), 124-128
Open this publication in new window or tab >>Shifts in polystyrene particle surface charge upon adsorption of the Pluronic F108 surfactant
2005 (Swedish)In: Journal of Colloid and Interface Science, Vol. 288, no 1, p. 124-128Article in journal (Refereed) Published
Abstract [en]

Electrical field-flow fractionation (ElFFF) and sedimentation field-flow fractionation (SdFFF) were used in combination to study the adsorption of the triblock polymeric surfactant, Pluronic F108 [(EO)129-(PO)56-(EO)129] to 200 nm polystyrene (PS) latex spheres. The SdFFF technique allowed an accurate determination of the mass of surfactant adsorbed on each particle from a solution of given concentration. To complement this isotherm study, we show that ElFFF can be used to measure fractional coverages of the formed electrically neutral surfactant layers on the charged PS particles. Through a combination of the two techniques it is possible to gain information about the structure of the adsorbate layer. Thus, when Pluronic F108 is taken up by the PS surface from solutions of low concentration, all three blocks appear to adhere to the surface as long as there is free space available. As the solution concentration increases and the fractional coverage reaches approximately 20%, the surface turns crowded enough to let the strongly adsorbing PPO blocks competitively displace the weakly adherent PEO blocks, which gradually rise to extend into the aqueous phase until the surface is fully saturated.

Keywords
Sedimentation field-flow fractionation, Electric field-flow fractionation, Pluronic adsorption, Polystyrene lattices, Competitive adsorption
Identifiers
urn:nbn:se:uu:diva-70668 (URN)
Available from: 2007-02-13 Created: 2007-02-13 Last updated: 2011-01-12
Andersson, M., Elihn, K., Fromell, K. & Caldwell, K. (2004). Surface attachment of nanoparticles using oligonucleotides. Colloids and Surfaces B: Biointerfaces, 34, 165-171
Open this publication in new window or tab >>Surface attachment of nanoparticles using oligonucleotides
2004 (English)In: Colloids and Surfaces B: Biointerfaces, Vol. 34, p. 165-171Article in journal (Refereed) Published
Abstract [en]

Colloidal polymer particles are widely used in a variety of applications ranging from chromatography to surface modified bioreactors in protein arrays. In the present study, surface attachment of polystyrene particles to a polystyrene substrate has been p

Keywords
oligonucleotides; nanoparticles; pyridyl disulphide
Identifiers
urn:nbn:se:uu:diva-48025 (URN)
Available from: 2007-02-13 Created: 2007-02-13 Last updated: 2011-01-12
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