Assessing the Collective Dynamics of Motile Cilia in Cultures of Human Airway Cells by Multiscale DDM

Abstract

The technique of differential dynamic microscopy is extended here, showing that it can provide a powerful and objective method of video analysis for optical microscopy videos of in vitro samples of live human bronchial epithelial ciliated cells. These cells are multiciliated, with motile cilia that play key physiological roles. It is shown that the ciliary beat frequency can be recovered to match conventional analysis, but in a fully automated fashion. Furthermore, it is shown that the properties of spatial and temporal coherence of cilia beat can be recovered and distinguished, and that if a collective traveling wave (the metachronal wave) is present, this has a distinct signature and its wavelength and direction can be measured.

Perspective: Differential dynamic microscopy extracts multi-scale activity in complex fluids and biological systems

“…The inflection point of this data (corresponding to a few 10 m in this sample) identifies a spatial scale in the system where dynamics is coherent. 40 is similar to the one used for the characterization of the viscoelastic constants in nematic liquid crystals 19 (Fig. 7).…”

“…However, those experiments do not allow for the type of control (cell-cell position, distance, orientation) that would enable tuning of interactions and thus to highlight the dominant mechanisms underpinning synchronization. These complications were tackled by Feriani et al 40 with the use of "air-liquid interface" cultures where the cells grow on a solid permeable membrane support, and are exposed to air on their apical side. A typical image taken across such a culture is shown in Fig.6a.…”

“…These cilia have a periodic (frequencies between a few Hz and 50 Hz) and well-defined beating pattern, and a key open question in many systems is how multiple cilia coordinate their beating for an efficient macroscopic fluid transport, particularly across many cells. Feriani et al 40 have investigated airway tissues, where in healthy physiological conditions the neighboring cilia act as phase-locked oscillators, forming a so-called "metachronal wave" that allows a continuous clearance of mucus from the lungs.…”

“…At a more general level, DDM represents a readily implemented technique that is extremely versatile and adaptable to almost any imaging system: bright-field 11 40 . It offers an immediate approach to the characterization of the type of motion from a study of the characteristic time ( ) vs q, which in the most frequent cases can be used for particle sizing or for the determination of the swimming velocity for bacteria, algae and micro-organisms.…”

Ciliary functional analysis: Beating a path towards standardization

“…Semiautomated program involve the selection of specific regions of interest (ROIs) to examine. Fully automated whole field analysis (WFA) automatically analyzes the entire captured image …”