Mesoporous silica nanomaterials

Giri S Trewyn BG Lin VSY, Mesoporous silica nanomaterial-based biotechnological and biomedical delivery systems, Nanomedicine, 2007, 2, 99 -111. 

The application of MPS in biosensor has received more and more attention in the past few years. It was reported that functionalized mesoporous silica nanomaterials have good biocompatibility to be internalized by animal and plant cells without posing any cytotoxicity issue in vitro [27-29], These findings may generate new types of drug/gene delivery and biosensor, particularly in the development of electrochemical biosensors. We will mainly discuss the advancements in morphology control and surface functionalization of MPS for proteins immobilization and the recent developments of proteins encapsulated MPS biosensors. 

The cellular uptake efficiency and kinetics together with the correlation between the particle morphology and aggregation of two kind, spherical and tubeshaped particles, of mesoporous silica nanomaterials (MSNs) were investigated... 

Helical nanomaterials Asymmetric No Cosurfactants used to modify synthesis of regular mesoporous silica nanomaterials [26]... 

Both spherical fluorescein isothiocyanate-doped mesoporous silica nanomaterials (S-FITC-MSN) and tubular fluorescein isothiocyanate-doped mesoporous silica nanomaterials (T-FITC-MSN) are synthesized to assess the rate of endocy-tosis based on several factors, as described by Trewyn et al. [18]. For general synthetic methods, the mesoporous silica nanomaterials can be prepared by mixing fluorescein isothiocyanate (FTIC) with 3-arninopropyltrunethoxysilane with anhydrous dimethylformamide (DMF) as solvent. N-cetyltrimethylammonium bromide (CTAB) is then dissolved in water and made basic with NaOH, followed by a temperature increase. TEOS is added dropwise to the CTAB solution, after which the other prepared solution is mixed in to produce S-FITC-MSN as an orange powder. 

Combining aspects of carbon and silicon chemistry while at the same time expanding the tool box of the periodic table, recently, a first report on the templated synthesis of mesoporous silicon oxycarbide (SiOC) and silicon carbonitride (SiCN) as analogs of the well-known mesoporous silica materials discussed in many chapters of the book has appeared (Fig. 25.5),58 opening an even wider horizon for the exploration of SiC-related nanomaterials in the fields covered in this book. 

Silver nanoparticles were also synthesized inside mesoporous silica by y-irradiationd These hard templates can also be used as nanoreactors to obtain nanomaterials of controlled shapes such as metal nanowires. Ichikawa and co-workers synthesized platinum and palladium nanowires in mesoporous silica However,... 

The growing of monodispersed RUO2 nanoparticles was achieved thanks to phosphonate groups contained within ordered mesoporous silicas. The use of mesoporous nanomaterials containing RUO2 nanoparticles (Ru02 Si02 nanomaterials) as catalytic filters for gas sensors, as well as after deposition as on-chip ... 

Petushkov A, Ndiege N, Salem AK, Larsen SC (2010) Toxicity of silica nanomaterials zeolites, mesoporous siliea, and ammphous silica nanoparticles. Chapter 7. Elsevier, Amsterdam Pillai O, Dhaniknla AB, Panehagnula R (2001) Curr Opin Chem Biol 5(4) 439-446 Pitt WG (2008) Adv Drag Deliv Rev 60 1095-1096... 

Most approaches to 1-D PPy nanomaterials have been dependent on the chemical and electrochemical polymerization methods using various templates such as AAO and polymer membranes [165,224-230], mesoporous silica [168,231], inorganic nanofibers [232], surfactants [233], and biomaterials [234,235]. The fibrillar and tubular PPy nanomaterials with controlled diameters were mainly fabricated within the cylindrical pores of AAO or PC membranes [165,225,226]. The 1-D PPy nanomaterials have shown the... 

Another area which was initiated during last year is development of chiral metal oxide based nanomaterials such as chiral Ti02 nanofibres and chiral ZrOj nanotubes. It is anticipated that these chiral metal oxide nanostructures will find very important applications as asymmetric catalysts. In addition the progress in the fabrication of mesoporous silica based chiral nanostructures e.g. helical architectures) should open new opportunities in chiral separation of enantiomeric compounds. 

There is, therefore, much work to do on the chemical engineering side. But the task is still more important for the chemistry of catalytic materials and deposition techniques. A personal feeling is that the activity of the catalytic substance should essentially be due to its external surface or that it should possess no porosity or only very wide pores. Nanoclusters (e.g., of monodispersed TiOj on mesoporous silica. Reference 11), micelles (e.g.. Reference 12), nanometer crystallites of zeolites (see, for example. Reference 13), and mesoporous solids could be candidates. An ample choice is possible in a period where nanomaterials are the object of intense research (see, for example. Reference 14). 

In this chapter we review the current state of research on symmetric and asymmetric silica nanomaterials, or nanosUica, in terms of their synthesis, characterizahon and applications. Both, catalyticaUy and noncatalytically grown nanosilica are discussed, and several types of application for these nanomaterials are described. For asymmetric nanosihca, the focus is on helical nanosilica such as silica nanocoils and other heh-cal nano silica, whereas for symmetric silica nanomaterials the discussion covers more general forms of nanosilica, including nanoparticles, mesoporous nanomaterials and sihca nanotubes. 

Many of the proposed magnetic nanomaterials for the applications as contrast agents for MRI are coated by micro- and mesoporous silica obtained by standard sol-gel procedures. The essential nontoxicity of silica, the existence of simple functionalization procedures for surface silanol groups and their porosity, made this material the ideal choice for the production of multifunctional contrast agents (MRI and luminescent) with capability of drug delivery. 

Table 26.1 Magnetic nanomaterials for the applications as contrast agents for magnetic resonance imaging (MRI) coated by micro- and mesoporous silica obtained by standard sol-gel procedures.

---