Mesoporous silica nanoparticles

Figure 16.6 DNA-coated gold-capped mesoporous silica nanoparticle loaded with (3-estradiol, employed for the simultaneous delivery of a gene and its promoter into plant cells.

Mesoporous silica containers can be used as inhibitor hosts with controlled release properties triggered at the beginning of the corrosion process in response to local pH changes. For instance, mesoporous silica nanoparticles covered with polyelectrolyte layers can be loaded with an inhibitor (2-(benzothiazol-2-ylsulfanyl)-succinic acid) prior to introduction into a hybrid zirconia-silica sol-gel film. This hierarchical design avoids spontaneous release of the inhibitor by the formation of a polyelectrolyte shell over the container s outermost surface. 

Slowing II Trewyn BG Giri S Lin VSY, Mesoporous silica nanoparticles for drug delivery and biosensing applications, Adv. Funct. Mater, 2007, 17, 1225-1236. 

Fig. 34 Example of mechanized mesoporous silica nanoparticles (MSNPs). SEM (a) and TEM (b) images show the structure and morphology of the MSNP platform [238]. (c) Structural formula of the a-cyclodextrin-based snap-top rotaxane that blocks the pores of an enzyme-cleavable mechanized MSNP. The stopper is connected to the stalk (dumbbell) by an ester or an amide bond [254]. (d) Release profile of rhodamine B from the snap-top MSNP. The addition of an esterase enzyme cleaves the ester bond, releasing the stopper, a-cyclodextrin, and cargo from the nanoparticles, which is monitored by the fluorescence intensity of rhodamine B. Controls employing an amide bond snap-top or deactivated enzyme do not release significant amounts of cargo...

As an intermediate between solid supported layers and the inherent dynamic and nanostructured properties of phospholipid vesicle supports, silica and especially mesoporous silica nanoparticles may provide interesting platforms for dynamic bilayers. Previous studies have shown that stable bilayers can form on both amorphous [102] or functional silica [103, 104] and mesoporous nanoparticles [105] or membranes [106]. This type of biomimetic carrier has great potential as a type of trackable stabilized membrane capable of displaying cellular targeting elements in a close to natural configuration. 

Fig. 27.5. Mesoporous silica nanoparticles as novel drug delivery systems, (a) Cocondensation method to form functionalized mesoporous silica structures in a surfactant template synthesis, (b) TEM image of mesoporous silica nanoparticles and sketch of a novel drug delivery particle which contains functionalized pores, closed by a gate, and is decorated with ligands for cell targeting, (c) Cell targeting by ligand-receptor interaction at the cell membrane, endosomal uptake and controlled release after pH change from early to late endosome...

H.P. Lin and C.P. Tsai, Synthesis of Mesoporous Silica Nanoparticles from a Low-concentration C(n)TMAX-Sodium Silicate Components. Chem. Lett., 2003, 32, 1092-1093. 

Li F, Wang ZY, Stein A (2007) Shaping mesoporous silica nanoparticles by disassembly of hierarchically porous structures. Angew Chem Int Ed 46 1885 Lebeau B, Fowler CE, Mann S, Farcet C, Charleux B, Sanchez C (2000) Synthesis of hierarchically ordered dye-functionalised mesoporous silica with macroporous architecture by dual templating. J Mater Chem 10 2105... 

Lu J, Liong M, Zink JI, Tamanoi F. Mesoporous silica nanoparticles as a delivery system for hydrophobic anticancer drugs. Small 2007 3 1341-1346. 

Martin-Ortigosa, S., Peterson, D.J., Valenstein, J.S., Lin, V.S., Trewyn, B.G., l.yznik, L.A., et al., 2014. Mesoporous silica nanoparticle-mediated intracellular ere protein delivery for maize genome editing via loxp site excision. Plant Physiol. 164 (2), 537—547. 

In a series of papers Mou and co-workers described the synthesis of mesoporous silica nanoparticles (MSNs) that contain Gd complexes for cell imaging (Figure 7.3). The silica particles are formed by the hydrolysis of TEOS in the presence of CTAB in aqueous ammonia. In the first such particle, a 100 x 425 75 nm nanorod (Gd-Dye MSN-R), formed by reaction with an amidopro-pyltrimethoxysilane tethered DTPA, GdDTPA was located in pores of 2.2 run diameter. The particles were rendered bifunctional by the attachment of the... 

A cationic polymer, quaternized poly bis(2-chloroethyl) ether-a/M,3-bis[3-(dimethylamino)propyl]urea was used to obtain cationic polymer-mesoporous silica nanoparticles. The material was studied as the DDS for ibuprofen and captopril, and showed well-sustained release profiles. 

Kim, D., Finkenstaedt-Quinn, S., Hurley, K.R., Buchman, J.T., Haynes, C.L. On-chip evaluation of platelet adhesion and aggregation upon exposure to mesoporous silica nanoparticles. Analyst 139, 906-913 (2014). doi 10.1039/c3an01679j... 

Modification of mesoporous silica nanoparticles using the bifunctional strategy, post-synthesis grafting, and backfilling strategy in order to make them suitable for drug delivery applications was reported (Lu et al. 2007). The modified nanoparticles were able to deliver the water insoluble drug camptothecin into different types of human cancer cells (Johansson et al. 2008). 

Liu D, Geng L, Fu Y, Dai X, Lti C (2011) Novel nanocomposite membranes based on sulfonated mesoporous silica nanoparticles modified sulfonated polyimides for direct methanol fuel cells. J Membr Sci 366 251-257... 

Trewyn BG, Slowing 11, Giri S, Chen H-T, Lin VS-Y. Synthesis and functionalization of a mesoporous silica nanoparticle based on the sol—gel process and applications in controlled release. Ace Chem Res 2007 40 846-53. 

J. (2012) Controllable delivery of hydrophilic and hydrophobic drugs from electrospun poly(lactic-co-glycolic acid)/mesoporous silica nanoparticles composite mats. /. Biomed. Mater. Res. Parts, lOOB, 2178-2186. 

Three organically functionalized mesoporous silica nanoparticles, MSN-COOH, MSN-SOjH, and MSN-SH, were synthesized. TEOS and a corresponding organo-trimethoxysilane (10 mol% to the TEOS) were added dropwise to an aqueous solution... 

FIGURE 4.3 Schematic representation of the utilization of anionic organoalkoxysilanes for controlling the functionalization of the mesoporous silica nanoparticle (MSN) materials. The MCM-41 type mesoporous channels are illustrated by the parallel stripes shown in the TEM micrograph of the MSN-SH material. (Figure modified from Reference 21.)... 

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