RESONATOR-BASED EVALUATION OF FLUID VISCOELASTIC PROPERTIES

摘要

An analysis technique for determining complex qualitative and quantitative contributions to the viscoelastic properties of a film in contact with or in close proximity to a surface. Based on an assumption that the viscosity of the surface of a fluid film that is opposite to a surface at which the film interacts with the surface changes negligibly, the invention derives representative parameters for the mass and elasticity of the film as a whole as well as a qualitative parameter that is representative of a typical single particle within the film. These representative parameters can be used to classify the film, and in the case of blood or other bodily fluids, can be used to identify pathological conditions. The invention is applicable to all types of liquids that physically interact with a surface, e.g. by exhibiting a coupling effect, adhesion or the like.

主权项

1. A method of evaluating viscoelastic properties of a fluid film as it interacts with a surface, the method comprising:
applying a fluid under test to an oscillating surface of a mechanical resonator sensor, wherein the fluid comprises particles, which, after the fluid under test is applied to the oscillating surface, begin to couple to the oscillating surface to form a film that interacts with the oscillating surface; detecting a change in resonant frequency Δf and a change in half bandwidth ΔΓ of a resonance peak exhibited by the mechanical resonance sensor as the fluid under test forms the film that interacts with the oscillating surface; and evaluating two or more of:
a first quantitative characteristic indicative of an effective mass M{tilde over (t)} of the film interacting with the oscillating surface,a second quantitative characteristic indicative of an effective elasticity u{tilde over (t)} of the film interacting with the oscillating surface, anda qualitative characteristic indicative of a rigidity factor φ of an individual particle within the film interacting with the oscillating surface, wherein:Mt~=B[Δf(tz)-Δf(t)-ΔΓ(tz)2ΔΓ(t)+ΔΓ(tz)]μt~=A[ΔΓ(t)2ΔΓ(tz)2-ΔΓ(tz)2ΔΓ(t)2]andϕ=Cμt~Mt~ where A, B and C are coefficients of proportionality, Δf(t) and ΔΓ(t) are respectively the detected change in resonant frequency and half bandwidth of the resonant peak at a detection time t when the film has formed and is interacting with the oscillating surface, and Δf(tz) and ΔΓ(tz) are respectively the detected change in resonant frequency and half bandwidth of the resonant peak at a pre-interaction time tz which is after the fluid is applied but before any particles couple to the oscillating surface, where tz