Comparison of surface plasmon resonance and quartz crystal microbalance inthe study of whole blood and plasma coagulation

The coagulation of blood plasma and whole blood was studied with a surface plasmon resonance (SPR) based device and a quartz crystal microbalance inst rument with energy dissipation detection (QCM-D). The SPR and QCM-D respons e signals were similar in shape but differing in time scales, reflecting di fferences 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 wit hin the evanescent field is sufficient for detection with SPR. Both the SPR signals and the QCM-D frequency and dissipation shifts showed dependency o n concentrations of coagulation activator and sensitivity to heparin additi ons. The ratio of dissipation to frequency shifts, commonly considered to r eflect 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 understandin g of the blood coagulation processes as well as the potential of the two me thods in the clinic and in research are discussed. (C) 2000 Elsevier Scienc e S.A. All rights reserved.