Mesoporous Silica Nanoparticles: nano-dimensional but powerful

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Dr. Nikola Knezevic, Kristina Živojević & Minja Mladenović
BioSense Institute

Mesoporous silica is a type of colloidal silica, obtained by condensation of silica precursors into ordered mesostructure using a template-assisted sol-gel mechanism. It involves the base-catalyzed hydrolysis and condensation of the liquid alkoxide precursors into a colloidal solution (sol), which further forms an ordered network (gel) of siloxane bridges, in a process usually regarded as inorganic polymerization. When the process is performed in the presence of a structure-directing agent (surfactant), nanomaterials with mesoporous structuring are synthesized and final highly porous nanoparticles are obtained after removal of the surfactant by extraction or calcination.

According to the International Union of Pure and Applied Chemistry (IUPAC), meso materials have a pore size in a range from 2 to 50 nm. Mesoporosity also enriches material with a high surface area (>1,000 m2/g) and large pore volume (>1 cm3/g).
Size, morphology and porosity features can be adjusted by modifying solvents, precursors, additives, surfactants, pH of the solution, temperature and stirring rate, which opens vast possibilities in synthesizing nanoparticles for a plethora of applications.

The introduction of organic groups within the silica framework or onto the silica surface endows materials with countless combinations of properties, including control of charge and silanol density. Additionally, particles can be constructed with hollow, magnetic or quantum dot cores. Particularly interesting opportunities exist for designing multifunctional nanosystems through selective modifications of the external surface and the surface inside the mesopores, loadingand entrapping cargo molecules with pore-capping molecules or nanoparticles, for achieving stimuli-responsive cargo delivery.

IPANEMA and Mesoporous Silica Nanoparticles

Within IPANEMA project, core/shell magnetic mesoporous silica nanoparticles (MMSNs) containing superparamagnetic core nanoparticles and characterized with ordered porosity and high specific surface area are to be used for pre-concentration of DNA. Use of such interaction of DNA with nanoparticles will enable IPANEMA researchers to achieve higher sensitivity and selectivity in sensing. Additionally, facile isolation of DNA from the analyte sample might be enabled through magnetic separation. Further possibilities also exist in application of MMSNs for magnetic sensing, where their higher surface could provide enhanced opportunities for functionalization and better sensing specificity.

Interproject collaboration

IPANEMA team members, Dr. Nikola Knezevic and Ph.D. students Minja Mladenović and Kristina Živojević continuously work on synthesis, characterization and different applications of MSNs and MMSNs. These efforts are focused on drug delivery, cancer therapy and diagnostics (theranostics), with newer research also involving applications of MSNs for biosensing and water purification, in collaboration with other members of the IPANEMA project and the Biosense Institute. As a result of such collaborations, the IPANEMA project coordinator, Dr. Ivana Gadjanski Stanic is also a team member in the new PRECAST project, whose Principal Investigator is Dr. Nikola Knezevic. This research was supported by the Science Fund of the Republic of Serbia. The overall objective of PRECAST project is to improve knowledge in the field of personalized medicine. PRECAST is engaged in the development of silica-based nanomaterials as contrast agents in targeted magnetic resonance imaging (MRI) and treatment of Glioblastoma multiforme (GBM). The new nanomaterials would enable strong and selective contrast enhancement at the GBM tumor location. The obtained information from MRI measurements could be also applicable for development of highly efficient nanomaterials for targeted and personalized treatment of patients suffering from GBM.