Low-Temperature Strategy to Synthesize Highly Ordered Mesoporous Silicas with Very Large Pores

Fan, Jie; Yu, Chengzhong; Lei, Jie; Zhang, Qiang; Li, Tingcheng; Tang, Bo; Zhou, Wuzong; Zhao, Dongyuan

doi:10.1021/ja052619c

Cited by 267 publications

(327 citation statements)

References 17 publications

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“…Conversely, the absence of FC-4 causes the production of mesoporous silica with micrometer size particles (8À12 μm) as it is the case for standard FDU-12-type materials. 9,29 Nitrogen physisorption results of the sample LP-MSNs (Supporting Information, Figure S1) demonstrate a type IV isotherm with H2 hysteresis loop at high relative pressures indicating the existence of large mesopores with cage-like structures. 29 The pore size was determined using the BroekhoffÀde Boer (BdB) method 30 considering spherical shape pores, although deviation from ideal spherical pore morphology is possible here.…”

Section: Resultsmentioning

confidence: 99%

“…It is believed that the usage of low temperature enhances the penetration of the swelling agent TMB (1,3,5-trimethylbenzene) into the hydrophobic core of the micelles during synthesis, which ultimately results in an extra enlargement of pore size (27.9 nm). 15,29,31 The use of high hydrothermal treatment temperature of 140°C contributed in the widening of the entrance pore size above 13.4 nm. Owing to the small spherical particle size and the large pore size (large unit cell), the mesostructure symmetry of the sample is difficult to determine by powder X-ray analysis (XRD).…”

Section: Resultsmentioning

confidence: 99%

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Poly-l-lysine Functionalized Large Pore Cubic Mesostructured Silica Nanoparticles as Biocompatible Carriers for Gene Delivery

et al. 2012

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Large pore mesoporous silica nanoparticles (LP-MSNs) functionalized with poly-l-lysine (PLL) were designed as a new carrier material for gene delivery applications. The synthesized LP-MSNs are 100–200 nm in diameter and are composed of cage-like pores organized in a cubic mesostructure. The size of the cavities is about 28 nm with an entrance size of 13.4 nm. Successful grafting of PLL onto the silica surface through covalent immobilization was confirmed by X-ray photoelectron spectroscopy, solid-state 13C magic-angle spinning nuclear magnetic resonance, Fourier transformed infrared, and thermogravimetric analysis. As a result of the particle modification with PLL, a significant increase of the nanoparticle binding capacity for oligo-DNAs was observed compared to the native unmodified silica particles. Consequently, PLL-functionalized nanoparticles exhibited a strong ability to deliver oligo DNA-Cy3 (a model for siRNA) to Hela cells. Furthermore, PLL-functionalized nanoparticles were proven to be superior as gene carriers compared to amino-functionalized nanoparticles and the native nanoparticles. The system was tested to deliver functional siRNA against minibrain-related kinase and polo-like kinase 1 in osteosarcoma cancer cells. Here, the functionalized particles demonstrated great potential for efficient gene transfer into cancer cells as a decrease of the cellular viability of the osteosarcoma cancer cells was induced. Moreover, the PLL-modified silica nanoparticles also exhibit a high biocompatibility, with low cytotoxicity observed up to 100 μg/mL.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Poly-l-lysine Functionalized Large Pore Cubic Mesostructured Silica Nanoparticles as Biocompatible Carriers for Gene Delivery

et al. 2012

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“…In order to optimize the dispersion degree and particle size of the benzene-silica hollow nanosphere, KCl was added in the initial mixture because the inorganic salts were always used to adjust the structure and morphology of the mesoporous materials in combination with nonionic copolymer surfactant. 24, 25 The TEM NBSB-423-105 was synthesized using 1,4-bis(trimethoxysilylethyl)benzene (BTSEB) as the silane precursor. To our delight, hollow nanospheres could still be observed in the TEM image of NBSB-423-105, though the contrast between the core and shell is not as clear as that of NES and NBS samples.…”

Section: Synthesis Of Silica Particlesmentioning

confidence: 99%

Tunable Assembly of Organosilica Hollow Nanospheres

et al. 2009

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Hollow nanospheres with a particle size of less than 25 nm have been successfully fabricated using an ethylene-, phenylene-, and 1,4-diethylphenylene-bridging silane precursor with F127 as a soft template under an acidic medium. As the size and flexibility of the bridging organic group increases, it is more and more difficult for the formation of hollow nanospheres. The organic additive, 1,3,5-trimethylbenzene, could finely tune the particle size of the nanosphere from 12 to 25 nm. It was found that silane precursors with hydrophobicity and slow hydrolysis rate favor the formation of hollow nanospheres and hydrophilic silane precursors such as tetramethoxysilane induce the formation of mesostructured bulk materials. Under the current synthesis conditions, carefully tuning the interaction between templates and silica species, organosilica hollow nanospheres with controlled composition can be successfully obtained.

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“…18 Recently, an extra-large pore ordered mesoporous silica FDU-12 with pore size up to 27 nm has been successfully synthesized. 19 Its large pore size and three-dimensional pore connectivity present the material as a superior choice over MCM-41 and SBA-15 for the immobilization of large enzymes, especially with respect to mass transfer and pore blocking. 20 However, previous reports showed that surface functionalization of the silica support materials is necessary prior to enzyme immobilization such that the interaction between the silica surface and enzyme is maximized, and a beneficial microenvironment for optimum catalytic activity of the enzyme is created.…”

Section: Introductionmentioning

confidence: 99%

Functionalized Mesoporous Silica with Very Large Pores for Cellulase Immobilization

et al. 2010

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Organo-functionalized FDU-12 type silicas exhibiting large pore sizes and ordered mesoporous structures were synthesized at low reaction (15°C) and high hydrothermal (160°C) temperatures via the co-condensation of tetraethoxysilane (TEOS) with a suite of organosilanes, i.e., 3-aminopropyltriethoxysilane (APTES), 3-mercaptopropyltrimethoxysilane (MPTMS), vinyltrimethoxysilane (VTMS), and phenyltrimethoxysilane (PTMS), in the presence of structure directing micelles formed using the surfactant pluronic F127 and the pore enlarging reagent trimethylbenzene (TMB). Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) confirmed that all synthesized materials possessed a face-centered cubic mesostructure (space group Fm3 j m), while nitrogen sorption analyses showed that the synthesized materials had extra large pores with cavity sizes of up to 25.4 nm and entrance sizes of up to 10.8 nm. X-ray photoelectron spectroscopy (XPS) and 13 C solid-state magic-angle spinning nuclear magnetic resonance ( 13 C-MAS NMR) measurements verified the incorporation of the different organosilanes into the silica network and more importantly on the inner and outer surfaces of the materials. As-obtained mesoporous silicas were tested in protein immobilization studies using bovine serum albumin and the cellulose-hydrolyzing enzyme cellulase, which in itself is a mixture of three large enzymes. Enzyme immobilization efficiency, activity, and stability varied significantly with organic functionality due to size exclusion effects at pore entries, electrostatic and hydrophobic interactions between the organo-functionalized surfaces and the enzymes, and conformational changes of the enzymes which can occur on some of the material surfaces. As a result, phenyl (PTMS)-and thiol (MPTMS)-functionalized FDU-12 mesoporous silicas had a very low adsorption capacity of proteins because of their small pore sizes. Amino (APTES)-functionalized FDU-12 mesoporous silica showed the highest adsorption amount of proteins yet the lowest activity of immobilized cellulase. Cellulase immobilization on vinyl (VTMS)-functionalized FDU-12 mesoporous silica appeared to be the most promising approach, since it occurred with high efficiency, maintained enzyme activity, and provided temporal enzyme stability.

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Low-Temperature Strategy to Synthesize Highly Ordered Mesoporous Silicas with Very Large Pores

Abstract: By employing a novel low-temperature synthetic pathway, highly ordered cubic mesoporous materials with hitherto the largest pores (up to 27 nm) and unit cells (up to 44 nm) have been successfully obtained.

Cited by 267 publications

References 17 publications

Poly-l-lysine Functionalized Large Pore Cubic Mesostructured Silica Nanoparticles as Biocompatible Carriers for Gene Delivery

Poly-l-lysine Functionalized Large Pore Cubic Mesostructured Silica Nanoparticles as Biocompatible Carriers for Gene Delivery

Tunable Assembly of Organosilica Hollow Nanospheres

Functionalized Mesoporous Silica with Very Large Pores for Cellulase Immobilization

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