Morphology Control of Mesoporous Silica Particles Using Bile Acids as Cosurfactants

Abstract

Morphology control and tuning of nanomaterials are crucial to determine their properties and applications. Solutions based on different synthetic methodologies have been proposed, and in general they required variation of several parameters. Here, a new facile and cost-effective bottom-up strategy to control the morphology of mesoporous silica particles is presented. Specifically, catanionic templating systems composed of bile acids and CTAB enable the production of submicrometer MCM-41 particles of various shapes, high porosity, and remarkable features. The variation of a single component, the bile acid, leads to the preparation of particles with different morphologies. For instance, small (<500 nm) well-separated hexagonal platelets and twisted rods, with tunable aspect ratio and chiral pore channels, were prepared. Experiments aimed at elucidating the role of the bile acids showed that the control of shape is due to the specific interactions between bile acids and CTAB.

Metal Species–Encapsulated Mesoporous Silica Nanoparticles: Current Advancements and Latest Breakthroughs

“…However, the convenient self‐assembly of surfactant and silica species is usually based on the mutual interactions between them. It should be noted that the morphology and dimensions of MSNs utterly depend on the reaction kinetics of sol–gel chemistry, water content, and temperature, as well as the pH value of the reaction medium 4j,68. In addition, several other experimental factors, including surfactant‐silica interactions, assembly kinetics, silica condensation, nucleation and growth rates, influence the eventual morphology of MSNs.…”

“…In some instances of using silica species as the core, the pore‐directing surfactant templates are coated over the solid silica cores for the efficient deposition of silica and the convenient generation of mesopores, as both the core and the shell possess a similar charge. However, it should be noted that the operating conditions during fabrication should be optimized to generate core–shell architectures with different shapes (spheres, cubes, and rods, among others 14e,f,28b,32a,c,68,77. Unlike the conventional organic polymer or surfactant coating approaches used for MNPs, the silica shell coating of the MNP cores offers numerous benefits to the metals, such as increasing the thermal stability, avoiding undesired aggregation and premature leakage, and providing robust protection against nanoparticle sintering, among other effects 28b,64…”

“…In this context, it is possible to tailor the size and morphology of the MSNs, resulting in the desired physicochemical attributes that are appropriate for diverse applications 4m. It is noteworthy that De Cola and coworkers recently fabricated MSNs with distinct morphologies ranging from hexagonal platelets to twisted rods at a controlled aspect ratio by using bile acids as cosurfactants, indicating that the shapes were significantly controlled due to the specific interactions between the CTAB and bile acids . These diverse shapes could be appropriately suitable for different applications, such as attractive templates for separation operations, indicating that this cost‐effective strategy paves a convenient means for morphology modulation of MSNs.…”

Nanoarchitectured Structure and Surface Biofunctionality of Mesoporous Silica Nanoparticles

“…In some of the instances, the use of bile acids as cosurfactants can tailor the physicochemical properties of MSNs, yielding diverse shapes, which could be well‐suited for separation operations and morphology modulation of MSNs. [ 23 ] However, change in the synthesis solution also play a crucial role, such as the utilization of sodium hydroxide and others. In this vein, triethanolamine is one of them providing the alkalescent environment, which results in ultrasmall, uniform‐sized MSNs with exceptional colloidal stability (20 nm) by avoiding the particle aggregation and rapid hydrolysis.…”

Bile Salts Caught in the Act: From Emulsification to Nanostructural Reorganization of Lipid Self-Assemblies

“…39 Various different lipid phase diagrams and structural changes upon interactions with different surfactants including bile salts have been intensively investigated over the last two decades. [40][41][42][43][44][45][46] We note, based on recent nutritional reports, that our studied non-lamellar self-assembled phases can occur and promote the digestion of food products such as human breast milk or mayonnaise and aid the absorption of oil-soluble food compounds and various nutraceuticals 31,[47][48][49] . In addition, monoglycerides and aliphatic alcohols are receiving a growing interest in the formulation of smart food and novel drug delivery systems, 30,[50][51][52] because as by-products of hydrolysis of common triglycerides, in particular monoglycerides are cheap and at the same time accepted food-grade materials.…”