Sol-Gel Synthesis of Mesoporous Silica Using a Protein Crystal Template

Mesoporous materials are useful for a wide range of applications, but control over the dimensions of the porous structure in this size regime remains challenging. Protein cages possess regular shape and many of them fall into the mesoporous size-region, making them potential template materials for inorganic matrices. Here, apoferritin single crystals are used as templates for the production of mesoporous silica. The high free volume and large pore size of the crystals enable silica precursor hydrolysis and condensation inside them and thus templated growth of a silica matrix. Apoferritin can be removed by calcination to yield solid state structures with the crystalline periodicity retained in the mesopores. We foresee that the method is applicable also for other protein cages, enabling production of mesoporous silica with various pore dimensions.