Hierarchical architectures by synergy between dynamical template self-assembly and biomineralization

Diatoms, shells, bones and teeth are exquisite examples of well-defined structures, arranged from nanometre to macroscopic length scale, produced by natural biomineralization using organic templates to control the growth of the inorganic phase 1 , 2 , 3 , 4 , 5 , 6 . Although strategies mimicking Nature have partially succeeded in synthesizing human-designed bio-inorganic composite materials 7 , 8 , 9 , 10 , our limited understanding of fundamental mechanisms has so far kept the level of hierarchical complexity found in biological organisms out of the chemists’ reach 11 . In this letter, we report on the synthesis of unprecedented double-walled silica nanotubes with monodisperse diameters that self-organize into highly ordered centimetre-sized fibres. A unique synergistic growth mechanism is elucidated by the combination of light and electron microscopy, synchrotron X-ray diffuse scattering and Raman spectroscopy. Following this growth mechanism, macroscopic bundles of nanotubules result from the kinetic cross-coupling of two molecular processes: a dynamical supramolecular self-assembly and a stabilizing silica mineralization. The feedback actions between the template growth and the inorganic deposition are driven by a mutual electrostatic neutralization. This ‘dynamical template’ concept can be further generalized as a rational preparation scheme for materials with well-defined multiscale architectures and also as a fundamental mechanism for growth processes in biological systems.