Abstract：
:This study is concerned with reconciling theoretical modelling of the fluid flow in the airway surface liquid with experimental visualisation of tracer transport in human airway epithelial cultures. The airways are covered by a dense mat of cilia of length approximately 6 microm beating in a watery periciliary liquid (PCL). Above this there is a layer of viscoelastic mucus which traps inhaled pathogens. Cilia propel mucus along the airway towards the trachea and mouth. Theoretical analyses of the beat cycle (smith et al., 2006b; Fulford and Blake, 1986) predict small transport of PCL compared with mucus, based on the assumption that the epithelium is impermeable to fluid. However, an experimental study (Matsui et al., 1998) indicates nearly equal transport of PCL and mucus. Building on existing understanding of steady advection-diffusion in the ASL (Blake and Gaffney, 2001; Mitran, 2004), numerical simulation of an advection-diffusion model of tracer transport is used to test several proposed flow profiles and to test the importance of oscillatory shearing caused by the beating cilia. A mechanically derived oscillatory flow with very low mean transport of PCL results in relatively little 'smearing' of the tracer pulses. Other effects such as mixing between the PCL and mucus, and significant transport in the upper part of the PCL above the cilia tips are tested and result in still closer transport, with separation between the tracer pulses in the two layers being less than 9%. Furthermore, experimental results may be replicated to a very high degree of accuracy if mean transport of PCL is only 50% of mucus transport, significantly less than the mean PCL transport first inferred on the basis of experimental results.
journal_name
Bull Math Bioljournal_title
Bulletin of mathematical biologyauthors
Smith DJ,Gaffney EA,Blake JRdoi
10.1007/s11538-006-9163-zsubject
Has Abstractpub_date
2007-04-01 00:00:00pages
817-36issue
3eissn
0092-8240issn
1522-9602journal_volume
69pub_type
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