| 1. |
- Vikinge, Trine P., et al.
(författare)
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Blood plasma coagulation studied by surface plasmon resonance
- 1999
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Ingår i: BIOMEDICAL SENSORS, FIBERS, AND OPTICAL DELIVERY SYSTEMS, PROCEEDINGS. - : SPIE - International Society for Optical Engineering. ; , s. 107-114
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Konferensbidrag (refereegranskat)abstract
- A surface plasmon resonance (SPR) apparatus was used to investigate blood plasma coagulation in real-time as a function of thromboplastin and heparin concentrations. The physical reason for the SPR signal observed is discussed and 3 different models are proposed. The response curves were analyzed by multivariable curve fitting followed by feature extraction. Interesting parameters of the sigmoid curves were lag time, slope and maximum response. When thromboplastin concentrations were increased, the lag-time decreased and the slope of the curve increased. A prolonged clotting time was mostly followed by increased maximum response, with exception for samples with no or very little thromboplastin added. High heparin concentrations changed the clotting kinetics, as seen from the lag-time vs. slope relation. Atomic force microscopy (AFM) pictures of sensor surfaces dried after completed clotting, revealed differences in fibrin network structures as a function of thromboplastin concentration, and fiber thickness increased with lower thromboplastin concentration. The results correlate well with present common methods.
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| 2. |
- Vikinge, Trine P., et al.
(författare)
-
Blood plasma coagulation studied by surface plasmon resonance
- 2000
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Ingår i: Journal of Biomedical Optics. - : SPIE-Intl Soc Optical Eng. - 1083-3668 .- 1560-2281. ; 5:1, s. 51-55
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Tidskriftsartikel (refereegranskat)abstract
- A surface plasmon resonance (SPR) apparatus was used to investigate blood plasma coagulation in real time as a function of thromboplastin and heparin concentrations. The response curves were analyzed by curve fitting to a sigmoid curve equation, followed by extraction of the time constant. Clotting activation by thromboplastin resulted in increased time constant, as compared to spontaneously clotted plasma, in a dose dependent way. Addition of heparin to the thromboplastin-activated plasma counteracted this effect. Atomic force microscopy (AFM) pictures of sensor surfaces dried after completed clotting, revealed differences in fibrin network structures as a function of thromboplastin concentration, and the fiber thickness increased with decreased thromboplastin concentration. The physical reason for the SPR signal observed is ambiguous and is therefore discussed. However, the results summarized in the plots and the fibrin network properties observed by AFM correlate well with present common methods used to analyze blood coagulation.
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| 3. |
- Vikinge, Trine P., et al.
(författare)
-
Comparison of surface plasmon resonance and quartz crystal microbalance in the study of whole blood and plasma coagulation
- 2000
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Ingår i: Biosensors & bioelectronics. - 0956-5663 .- 1873-4235. ; 15:11-12, s. 605-613
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Tidskriftsartikel (refereegranskat)abstract
- The coagulation of blood plasma and whole blood was studied with a surface plasmon resonance (SPR) based device and a quartz crystal microbalance instrument with energy dissipation detection (QCM-D). The SPR and QCM-D response signals were similar in shape but differing in time scales, reflecting differences in detection mechanisms. The QCM-D response time was longer than SPR, as a physical coupling of the sample to the substrate is required for molecules to be detected by the QCM-method. Change of sample properties within the evanescent field is sufficient for detection with SPR. Both the SPR signals and the QCM-D frequency and dissipation shifts showed dependency on concentrations of coagulation activator and sensitivity to heparin additions. The ratio of dissipation to frequency shifts, commonly considered to reflect viscoelastic properties of the sample, varied with the concentration of activator in blood plasma but not in whole blood. Additions of heparin to the thromboplastin activated whole blood sample, however, made the ratio variation reoccur. Implications of these observations for the understanding of the blood coagulation processes as well as the potential of the two methods in the clinic and in research are discussed.
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