Optical coherence tomography for evaluating capillary waves in blood and plasma

Abstract

Capillary waves are associated with fluid mechanical properties. Optical coherence tomography (OCT) has previously been used to determine the viscoelasticity of soft tissues or cornea. Here we report that OCT was able to evaluate phase velocities of capillary waves in fluids. The capillary waves of water, porcine whole blood and plasma on the interfacial surface, air-fluid in this case, are discussed in theory, and phase velocities of capillary waves were estimated by both our OCT experiments and theoretical calculations. Our experiments revealed highly comparable results with theoretical calculations. We concluded that OCT would be a promising tool to evaluate phase velocities of capillary waves in fluids. The methods described in this study could be applied to determine surface tensions and viscosities of fluids for differentiating hematological diseases in the future potential biological applications.

Static and Dynamic Optical Analysis of Micro Wrinkle Formation on a Liquid Surface

“…OCT imaging techniques have also been increasingly developed and applied across a broad a range of different disciplines, for example, the non-invasive analysis of paintings for art history and conservation [24], and profiling surface membranes for reconfigurable optics applications [25]. OCT developments and applications which involve imaging liquids and liquid surfaces have included micro-rheology studies of simple and complex fluids [26], analysing capillary waves in biological fluids [27,28], droplet imaging [29] and interface imaging to study surface wettability [30], gelation [31], and evaporation [32].…”

Characterizing thrombus with multiple red blood cell compositions by optical coherence tomography attenuation coefficient

“…Over the last two decades, optical coherence tomography (OCT) has been developed to investigate biological tissues and fluids due to ample advantages: non‐invasive, non‐contact, high spatial resolution, real‐time measurement, no ionizing radiation, and high sensitivity to the topology of a surface [24–27]. The optical attenuation coefficient in OCT is a reliable indicator to characterize various biological tissues such as arterial wall [28, 29], atherosclerotic plaques [30–32], enamel in teeth [33, 34], lymph nodes [35, 36], urothelial carcinoma in bladder [37], retinal nerve fiber layer [38, 39], human colon tissue [40], cerebral cortex [41], skin lesions [42], prostate tissue [43], breast tissue [44], and retinal microvascular [45].…”

Optical coherence viscometry

“…For capillary waves in deep water, the wavelength has to be smaller than defined as the critical capillary length , g is negligible, and to have tanh( kh ) 1. 19 Simplifying, we can rewrite Eq. (12) as and the dispersion relation of capillary waves in deep water is Using the relationship , we obtain the group velocity = 1.5 .…”

“…The force was exerted on the fluid–air interface to produce capillary waves by coupling the transducer to the Mylar film bottom of a customized Petri dish such that the ultrasound waves travel through the fluid and interacts with the fluid–air interface at the focal point of the transducer. 19 In this case, there is no direct contact with the sample with the OCV system. The lateral focal size is approximately 510 μ m calculated using 23 which generates waves similar to the ripples on a water surface created by dropping a stone in a pond assuming ≫1.…”

“…The detailed protocol of plasma preparation can be found in Ref. 19 . The experiments were carried out at ambient temperature (22 1 °C) measured by a thermometer (TMD-56, Amprobe, WA).…”