2016/04/26 by William Weigand, W. J. Weigand, A. Messmore +16
Biochemistry, Genetics and Molecular Biology · Engineering · Pharmacology, Toxicology and Pharmaceutics · Physics and Astronomy · #Advanced Drug Delivery Systems #Biological Physics (physics.bio-ph) #FOS: Biological sciences #FOS: Physical sciences #Microfluidic and Bio-sensing Technologies #Proteoglycans and glycosaminoglycans research #Soft Condensed Matter (cond-mat.soft) #Tissues and Organs (q-bio.TO) #cond-mat.soft #physics.bio-ph #q-bio.TO
paper · pdf · doi:10.48550/arxiv.1604.07887
arxiv created 2016/04/26 · openalex publication_date 2016/04/26 · arxiv updated 2016/04/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We characterize the scale-dependent rheological properties of mucus from the Chaetopterus marine worm and determine the intrinsic lengthscales controlling distinct rheological and structural regimes. Mucus produced by this ubiquitous filter feeder serves a host of roles including filtration, protection and trapping nutrients. The ease of clean mucus extraction coupled with similarities to human mucus rheology also make Chaetopterus mucus a potential model system for elucidating human mucus mechanics. We use optically trapped microsphere probes of 2-10 microns, to induce oscillatory strains and measure mucus stress response. We show that viscoelastic properties are highly dependent on the strain scale (l) with three distinct regimes emerging: microscale: l1<4 microns, mesoscale: l2~4-10 microns, and macroscale: l3>10 microns. While mucus response is similar to water for l1 indicating that probes rarely contact the mucus mesh, for l2 the response is distinctly more viscous and independent of probe size, demonstrating that the mucus behaves as a continuum. However, this principally viscous mesoscale response is distinct from the largely elastic macroscopic mucus response. Only for l3 does the response mimic macroscopic elasticity, with rigid constraints strongly resisting microsphere displacement. Our results demonstrate that a uniform mesh model for mucus with a single lengthscale modulating the crossover from water-like to elastic is too simplistic. Rather, the mucus responds as a hierarchical network with a loose microscopic mesh controlling mechanics for l2, coupled with a mesoscale rigid scaffold responsible for the macroscopic gel-like mechanics beyond l3. Our results shed important new light onto the design of drug delivery platforms, preventing pathogen penetration, and improving filtration, coating and clearance capabilities of mucus.