Orienting the Pore Morphology of Core-Shell Magnetic Mesoporous Silica with the Sol-Gel Temperature. Influence on MRI and Magnetic Hyperthermia Properties.

Alexandre Adam,Paula Duenas-Ramirez,Philippe Choquet,Clémence Nadal,Pierre-Emmanuel Zorn,Sylvie Bégin-Colin,Ksenia Parkhomenko,Damien Mertz,Geoffrey Cotin

doi:10.3390/molecules26040971

Abstract

The controlled design of robust, well reproducible, and functional nanomaterials made according to simple processes is of key importance to envision future applications. In the field of porous materials, tuning nanoparticle features such as specific area, pore size and morphology by adjusting simple parameters such as pH, temperature or solvent is highly needed. In this work, we address the tunable control of the pore morphology of mesoporous silica (MS) nanoparticles (NPs) with the sol-gel reaction temperature (Tsg). We show that the pore morphology of MS NPs alone or of MS shell covering iron oxide nanoparticles (IO NPs) can be easily tailored with Tsg orienting either towards stellar (ST) morphology (large radial pore of around 10 nm) below 80 °C or towards a worm-like (WL) morphology (small randomly oriented pores channel network, of 3–4 nm pore size) above 80 °C. The relaxometric and magnetothermal features of IO@STMS or IO@WLMS core shell NPs having respectively stellar or worm-like morphologies are compared and discussed to understand the role of the pore structure for MRI and magnetic hyperthermia applications.

Highlights

Among the range of inorganic nanomaterials, mesoporous silica (MS) are appealing given their specific controlled pore morphology, high pore volume and large surface area [1,2,3]
For STMS NPs synthesis, the CTATos surfactant solution was heated up to the desired temperature (
Concerning worm-like mesoporous silica (WLMS) NPs, the temperature was set above 80 ◦ C and the solution was stirred more than one hour before TEOS addition. 80 ◦ C

Summary

Introduction

Among the range of inorganic nanomaterials, mesoporous silica (MS) are appealing given their specific controlled pore morphology, high pore volume and large surface area [1,2,3] Their synthesis process is usually robust and scalable and silanol groups at the MS surface allow to envision the grafting of a versatile range of chemical functions [4,5,6]. The most reported methods to synthesize MS NPs, which are adapted historically from well-established MCM41 MS nanoparticle synthesis [17,18], make use of hexadecyltrimethylammonium bromide (CTAB), a quaternary ammonium surfactant, which in the presence of silicate precursors, typically tetraethoxysilane (TEOS), and in basic conditions, self-organizes into a hexagonal micellar phase [19,20,21] This process results in MS NPs having an ordered hexagonal pore structure of ca. This process results in MS NPs having an ordered hexagonal pore structure of ca. 2.5–3.0 nm pore size, corresponding to the initial diameter of the micellar rods

Methods

Results

Conclusion