Bioinspired templates for the synthesis of silica nanostructures

Abstract

Herein we report a facile method for the preparation of hierarchical silica nanostructures through a biomimetic approach. Toward this goal, a protein-directed approach has been proposed to template silica into 3D architectures through a hydrogel matrix formed from physically cross-linked fibrinogen. The hydrogel matrix has tunable physicochemical properties based on the thermal unfolding of the main domains of the protein. The network structures of the gels that are obtained are quite similar but differ in the mean pore size and rheological properties. These nanopores are then filled with silica precursors, under acidic conditions, where the condensation reaction is initiated. The protein hydrogel template is subsequently removed by calcination. The final materials show two different topologies. The origin of these two topologies lies on the anisotropic shape of the fibrinogen, driving stochastic interactions with the inorganic precursor and thus generating sponge-like (normal interactions) and polygonal fiber (parallel interactions) architectures.