Measurement of the evolution of rigid and viscoelastic mass contributions from fibrin network formation during plasma coagulation using quartz crystal microbalance

The coagulation of blood plasma and the effect of fibrinogen concentration were studied with a quartz crystal microbalance (QCM), where frequency and half-width at half-maximum (bandwidth) values measured from the conductance spectrum near resonant frequency were used. Bandwidth change is an indicator of energy dissipation, allowing for an understanding of qualitative changes occurring during fibrin clot formation. Both frequency shift (Δf) and bandwidth shift (ΔΓ) were dependent on the concentration of fibrinogen in plasma. We defined a sum of squares function α (= Δf2/1000 + ΔΓ2/1000) that measures absolute changes in QCM resonant characteristics to semi-quantitatively include an overall contribution of adsorbed mass and elastic modulus components and a function β (= 1 − ΔΓ/Δf) that indicates qualitatively the nature of response based on its deviation from ideal Newtonian behaviour. Increasing concentration of fibrinogen resulted in an increase in the value of α, showing that a larger amount of fibrinogen results in larger amount of coupled viscoelastic mass. Changes in β indicated that the nature of changes occurring was very similar to Newtonian and that coupling of rigid-mass dominates the overall response in the early stage of coagulation and in the later stage growing elastic mass compensates some of the response.