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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-431-1

ISBN Online: 978-1-56700-430-4

First Thermal and Fluids Engineering Summer Conference
August, 9-12, 2015 , New York City, USA

EXAMINING MUCIN TYPE AND MORPHOLOGY EFFECTS ON MAMMALIAN MUCUS MECHANICAL AND MICROSTRUCTURAL PROPERTIES

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DOI: 10.1615/TFESC1.bio.013017

Resumo

Mucus is a heterogeneous and complex gel-like material present in many organ systems, such as the respiratory, gastrointestinal, and reproductive tracts. Mucus acts a barrier against bacteria, viruses, toxins, and foreign particles; thus, it is important to understand the mechanical and microstructural properties of this complex biofluid. The relationships between composition, physical characteristics, mechanical properties, microstructure-including the size, assembly and crosslinking interactions of polymeric mucin chains-and the physiological functions of mucus are not well understood. In this study, the nanomechanical and viscoelastic properties of mammalian lung mucus were measured using atomic force microscopy (AFM) and steady shear and small- and large-strain oscillatory shear flows. Mammalian lung mucus showed complex fluid behaviors including non-linear viscoelastic responses. Using large amplitude oscillatory shear (LAOS) rheological experiments, strain-stiffening was observed at low strain values and at large strain values the mucus exhibited strain-softening behavior. Nanomechanical properties, including Young's modulus, stiffness, and force-displacement curves, were measured using Peak Force Quantitative Nanomechanical Mapping in-situ under an aqueous environment. This is related to the observed aggregation and conformational changes of mucin-at both the micro- and nano-scale. As rheological and mechanical properties of lung mucus reported are linked to high-strain rate physiological processes, such as coughing, understanding how these properties change with disease and/or the introduction of foreign bodies is key to guiding new therapeutics and regulating respired particulates.