title: Fluid-flow-templated self-assembly of calcium carbonate tubes in the laboratory and in biomineralization: The tubules of the watering-pot shells, Clavagelloidea.
abstract: We show with laboratory experiments that self-assembled mineral tube formation involving precipitation around a templating jet of fluid - a mechanism well-known in the physical sciences from the tubular growth of so-called chemical gardens - functions with carbonates, and we analyse the microstructures and compositions of the precipitates. We propose that there should exist biological examples of fluid-flow-templated tubes formed from carbonates. We present observational and theoretical modelling evidence that the complex structure of biomineral calcium carbonate tubules that forms the 'rose' of the watering-pot shells, Clavagelloidea, may be an instance of this mechanism in biomineralization. We suggest that this is an example of self-organization and self-assembly processes in biomineralization, and that such a mechanism is of interest for the production of tubes as a synthetic biomaterial.
  
  
  
  The work discussed in the manuscript concerns the self-assembly of calcium carbonate micro-tubes and nano-tubes under conditions of fluid flow together with chemical reaction. We present the results of laboratory experiments on tube self-assembly together with theoretical calculations. We show how nature may already be making use of this process in molluscan biomineralization of the so-called watering-pot shells, and we propose that we may be able to take advantage of the formation mechanism to produce synthetic biocompatible micro- and nano-tubes.
authors.affiliation: Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA, UK. Electronic address: sssc1@cam.ac.uk.
authors.forename: Silvana S S
authors.initials: SSS
authors.lastname: Cardoso
authors.affiliation: Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, E-18100 Armilla, Granada, Spain; Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, E-18071 Granada, Spain. Electronic address: julyan.cartwright@csic.es.
authors.forename: Julyan H E
authors.initials: JHE
authors.lastname: Cartwright
authors.affiliation: Departamento de Estratigrafía y Paleontología, Universidad de Granada, E-18071 Granada, Spain; Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, E-18100 Armilla, Granada, Spain. Electronic address: acheca@ugr.es.
authors.forename: Antonio G
authors.initials: AG
authors.lastname: Checa
authors.affiliation: Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, E-18100 Armilla, Granada, Spain. Electronic address: ignacio.sainz@iact.ugr-csic.es.
authors.forename: C Ignacio
authors.initials: CI
authors.lastname: Sainz-Díaz
mesh_terms: D060105:Animal Shells / Q000737:chemistry / Q000648:ultrastructure; D000818:Animals; D049872:Bivalvia / Q000737:chemistry* / Q000648:ultrastructure; D002119:Calcium Carbonate / Q000737:chemistry*; D007091:Image Processing, Computer-Assisted; D007753:Laboratories; D008903:Minerals / Q000737:chemistry*; D012212:Rheology
chemical_list: D008903:Minerals; D002119:Calcium Carbonate
keywords: Biomimetics; Biomineral; Calcium carbonate; Chemical garden; Chemobrionics; Mollusc; Self-assembly