title: The biocomposite tube of a chaetopterid marine worm constructed with highly-controlled orientation of nanofilaments.
abstract: The ultrastructure of the self-constructed tube housing of the bioluminescent marine worm, Chaetopterus sp. reveals that the bio-nanocomposite tube comprises of multiple non-woven plies of multi-axially oriented organic nanofilaments (ø 50-1100nm) cemented together by an unstructured organic matrix binder. The thin-walled, impermeable tubes are bio-inspirational for conventional pipe technology. Orientation distribution analyses revealed that the dominant orientation angles of nanofilaments in the tube were 0°, ±45° and ±65°, which correlate well with optimal winding angles for 'man-made' fibre reinforced composite pipes subjected to specific loading conditions. Such a use of high aspect ratio nanofilaments in multi-axial laminates would impart toughness and flexibility to the tube structure, and facilitate rapid tube growth. While the tube production mechanism is not entirely known at this stage, our time-lapse studies show that, contrary to generic assumptions in literature, the worm actively, rapidly and sporadically produces and expands the tube.
authors.affiliation: Oxford Silk Group, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK. Electronic address: darshil.shah@zoo.ox.ac.uk.
authors.forename: Darshil U
authors.initials: DU
authors.lastname: Shah
authors.affiliation: Oxford Silk Group, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
authors.forename: Fritz
authors.initials: F
authors.lastname: Vollrath
authors.affiliation: Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La California 92093-0202, USA.
authors.forename: John
authors.initials: J
authors.lastname: Stires
authors.affiliation: Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La California 92093-0202, USA. Electronic address: ddeheyn@ucsd.edu.
authors.forename: Dimitri D
authors.initials: DD
authors.lastname: Deheyn
mesh_terms: D000818:Animals; D059001:Aquatic Organisms; D053761:Nanocomposites; D057139:Nanofibers; D011077:Polychaeta
keywords: Biological composites; Chaetopterus; Composite pipes and tanks; Marine polychaete; Parchment biomaterial; Tube housing; Ultrastructural organisation