Three-dimensional, three-vector-component velocimetry of cilia-driven fluid flow using correlation-based approaches...

Area of Science:

• Physiology
• Biophysics
• Fluid Dynamics

Background:

• Cilia-driven fluid flow is crucial in pulmonary and central nervous system physiology.
• Accurate measurement requires three-dimensional, three-component (3D3C) vector fields.
• Existing methods have limitations in microscale quantification.

Purpose of the Study:

• To develop and validate OCT-based velocimetry for microscale cilia-driven fluid flow.
• To achieve 3D3C vector field measurements.
• To enhance signal-to-noise ratio for synthesized flow velocity measurements.

Main Methods:

• Utilized two OCT-based approaches: digital particle image velocimetry (DPIV) and dynamic light scattering (DLS)-OCT.
• Generated 1D2C velocimetry measurements in Xenopus epithelium using directional DLS-OCT.
• Extended analysis to 3D3C measurements in Xenopus, mouse trachea, and cerebrospinal fluid using DPIV and DLS-OCT.
• Developed a framework for optimizing 3D3C measurements synthesized from 2D2C data.

Main Results:

• Demonstrated directional DLS-OCT for sub-1 mm/s cilia flow in Xenopus epithelium.
• Achieved 3D3C flow imaging of Xenopus cerebrospinal fluid and mouse trachea (sub-100 μm/s).
• Successfully synthesized 3D3C flow velocity from 2D2C measurements in non-orthogonal planes.

Conclusions:

• OCT-based 3D3C velocimetry offers a powerful tool for microscale fluid flow quantification.
• This technology has the potential to comprehensively characterize biological ciliated surfaces.
• Advances in physiological fluid dynamics research are enabled by these novel measurement techniques.