Issue 46, 2015 - Large-scale synthesis of cerebral cortical mesoporous silica matrix composites by Lanzhou Chemical Institute

Mesoporous silica material is a new type of inorganic material with high specific surface area, large pore volume, morphology and size controllability, which has the dual characteristics of mesoporous materials and silica materials, and has a wide
application prospect in catalysis, separation, biomedicine, sensors and other fields.
Cetyltrimethylammonium bromide, as a common cationic surfactant, is widely used in the preparation of mesoporous silica materials, but the mesoporous pore size of the prepared mesoporous silica materials is difficult to exceed 4nm
.
However, in many application fields, such as protein transport, etc.
, only when the mesoporous size is greater than 10 nm can meet the requirements of practical applications, and such materials are usually called macroporous mesoporous silica materials
.
At present, the known methods for preparing macroporous mesoporous silica materials have certain shortcomings, such as particle size is too large to meet the requirements of biomedicine, difficult to functionalize, difficult to produce on a large scale, etc
.

The team led by Wang Qihua, a researcher at the Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, has developed a simple and efficient method
for preparing monodisperse functionalized macroporous mesoporous silica-based materials suitable for large-scale production.
The group focused on the design of silica frame structures in an attempt to construct organic-inorganic hybrid shells through the introduction of
organosilanes.
Compared with the inorganic part, the organosilane hybrid part is less
resistant to alkali etching.
They used vinyltriethoxysilane and ethyl orthosilicate to co-hydrolyze/polycondensation to construct an organic-inorganic hybrid shell, and combined with the idea of selective etching, prepared the mesoporous silica-based core-shell structure
of cerebral cortex morphology in one pot.

By regulating the amount of organosilane and the etching time, they achieved effective control
of mesoporous pore size and material morphology.
The surface mesoporous pore size can reach up to 19nm, and the pore volume can reach 1.
29cm3g-1
.
In addition, partially etched oligosilicates will self-assemble again in the etched part, so that a large number of exposed vinyl groups exist in the mesopores, and temperature-responsive nanoreactors can be prepared by grafting temperature-responsive polymer poly (N-isopropylacrylamide) in the pores
.
In the preparation of intermediate layer mesoporous silica, fluorophores are introduced, which makes the final product show good fluorescence characteristics and expands the application prospects
of the prepared materials in the biological field.

This method provides a simple and efficient synthesis method for the large-scale preparation of macroporous mesoporous silica-based nanomaterials, and is expected to be applied
in nanoreactors, drug sustained-release systems and bioimaging.
(Lan)