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- Hansson, Kenny, 1972-, et al.
(författare)
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Surface plasmon resonance (SPR) analysis of coagulation in whole blood with application in prothrombin time assay
- 1999
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Ingår i: Biosensors & bioelectronics. - 0956-5663 .- 1873-4235. ; 14:8-9, s. 671-682
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Tidskriftsartikel (refereegranskat)abstract
- It is previously shown that surface plasmon resonance (SPR) can be used to study blood plasma coagulation. This work explores the use of this technique for the analysis of tissue factor induced coagulation, i.e. prothrombin time (PT) analysis, of whole blood and plasma. The reference method was nephelometry. The prothrombin time analysis by SPR was performed by mixing two volumes of blood/plasma, one volume of thromboplastin, and one volume of CaCl2 solution directly on a sensor surface. The measurements show good agreement between nephelometry and SPR plasma analysis and also between SPR plasma and whole blood analysis. The effect of anticoagulant treatment on the clotting times was significant both quantitatively and qualitatively. The impact on the SPR signal of different physiological events in the coagulation process is discussed, and tentative interpretations of the sensorgram features are given. The major advantage of the SPR method compared to nephelometry is the possibility to perform analysis on whole blood instead of plasma. In conclusion, SPR is a promising method for whole blood coagulation analysis.
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| 2. |
- Uvdal, Kajsa, et al.
(författare)
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Chemisorption of the dipeptide Arg-Cys on a gold surface and the selectivity of G-protein adsorption
- 2001
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 17:6, s. 2008-2012
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Tidskriftsartikel (refereegranskat)abstract
- Arginine-L-cysteine dipeptide adsorbates are used in this study as a model system for G-protein-coupled receptors (GPCRs). An arginine-containing model molecule is chosen because the GPCR a2A has been shown to include an arginine-rich region in the G-protein-binding part of the third intracellular loop, and the role of arginines by means of recognition is believed to exceed their positive charge. The dipeptide Arg-Cys is adsorbed to gold surfaces and the peptide monolayers are characterized. These peptide monolayers are then used for G-protein adsorption experiments to study the molecular interaction and binding. The molecular adsorption, orientation, and chemical binding of the peptide to the surface are studied by X-ray photoelectron spectroscopy and infrared reflection-absorption spectroscopy. A chemical shift in the S(2p) core level spectrum of the peptide adsorbate on gold shows that there is a strong molecular surface interaction consistent with a chemical binding of the peptide to the surface through the sulfur atom. With the cysteine part linked to the surface, the arginine part of the molecule is available for further adsorption processes. Monolayers of Arg-Cys, L-cysteine, and cysteamine are used for G-protein adsorption experiments. Adsorption of human serum albumin and human immunoglobulins on the same monolayers are studied for comparison. The analytical tool is surface plasmon resonance. Two different buffers are used for the adsorption studies, and the influence of buffer composition on protein adsorption is discussed.
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