Fabrication of uniform magnetic nanocomposite spheres with a magnetic core/mesoporous silica shell structure.
07 Jun 2005-Journal of the American Chemical Society (American Chemical Society)-Vol. 127, Iss: 25, pp 8916-8917
TL;DR: A novel kind of magnetic core/mesoporous silica shell nanospheres with a uniform particle diameter of ca.
Abstract: A novel kind of magnetic core/mesoporous silica shell nanospheres with a uniform particle diameter of ca. 270 nm was synthesized. The inner magnetic core endues the whole nanoparticle with magnetic properties, while the outer mesoporous silica shell shows high enough surface area and pore volume. The synthesized material is expected to be applied to targeted drug delivery and multiphase separation. The storage and release of ibuprofen into and from the pore channels of the mesoporous silica shell, as a typical example, are demonstrated.
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TL;DR: This review focuses on the synthesis, protection, functionalization, and application of magnetic nanoparticles, as well as the magnetic properties of nanostructured systems.
Abstract: This review focuses on the synthesis, protection, functionalization, and application of magnetic nanoparticles, as well as the magnetic properties of nanostructured systems. Substantial progress in the size and shape control of magnetic nanoparticles has been made by developing methods such as co-precipitation, thermal decomposition and/or reduction, micelle synthesis, and hydrothermal synthesis. A major challenge still is protection against corrosion, and therefore suitable protection strategies will be emphasized, for example, surfactant/polymer coating, silica coating and carbon coating of magnetic nanoparticles or embedding them in a matrix/support. Properly protected magnetic nanoparticles can be used as building blocks for the fabrication of various functional systems, and their application in catalysis and biotechnology will be briefly reviewed. Finally, some future trends and perspectives in these research areas will be outlined.
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TL;DR: Delamination of LDHs is an interesting route for producing positively charged thin platelets with a thickness of a few atomic layers, which can be used as nanocomposites for polymers or as building units for making new designed organic- inorganic or inorganic-inorganic nanomaterials.
Abstract: Layered double hydroxides (LDHs) are a class of ionic lamellar compounds made up of positively charged brucite-like layers with an interlayer region containing charge compensating anions and solvation molecules. Delamination of LDHs is an interesting route for producing positively charged thin platelets with a thickness of a few atomic layers, which can be used as nanocomposites for polymers or as building units for making new designed organic-inorganic or inorganic-inorganic nanomaterials. The synthesis of nanosized LDH platelets can be generally classified into two approaches, bottom-up and top-down. It requires modification of the LDH interlamellar environment and then selection of an appropriate solvent system. In DDS intercalated LDHs, the aliphatic tails of the DDS- anions exhibit a high degree of interdigitation in order to maximize guest-guest dispersive interactions. Bellezza reported that the LDH colloids can also been obtained by employing a reverse microemulsion approach.
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TL;DR: This review highlights the recent research developments of a series of surface-functionalized mesoporous silica nanoparticle (MSN) materials as efficient drug delivery carriers and envision that these MSN-based systems have a great potential for a variety of drug delivery applications.
2,373 citations
Cites methods from "Fabrication of uniform magnetic nan..."
...Furthermore, silica is used to enhance the biocompatibility of several drug delivery systems, such as magnetic nanoparticles [11–13], biopolymers [14], and micelles [15]....
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TL;DR: Recent research progress on the design of functional MSN materials with various mechanisms of controlled release, along with the ability to achieve zero release in the absence of stimuli, and the introduction of new characteristics to enable the use of nonselective molecules as screens for the construction of highly selective sensor systems are reviewed.
Abstract: Recent advancements in morphology control and surface functionalization of mesoporous silica nanoparticles (MSNs) have enhanced the biocompatibility of these materials with high surface areas and pore volumes. Several recent reports have demonstrated that the MSNs can be efficiently internalized by animal and plant cells. The functionalization of MSNs with organic moieties or other nanostructures brings controlled release and molecular recognition capabilities to these mesoporous materials for drug/gene delivery and sensing applications, respectively. Herein, we review recent research progress on the design of functional MSN materials with various mechanisms of controlled release, along with the ability to achieve zero release in the absence of stimuli, and the introduction of new characteristics to enable the use of nonselective molecules as screens for the construction of highly selective sensor systems.
1,574 citations
TL;DR: The introduction of magnetic nanoparticles in a variety of solid matrices allows the combination of well-known procedures for catalyst heterogenization with techniques for magnetic separation.
Abstract: Recovery and reuse of expensive catalysts after catalytic reactions are important factors for sustainable process management. The aim of this Review is to highlight the progress in the formation and catalytic applications of magnetic nanoparticles and magnetic nanocomposites. Directed functionalization of the surfaces of nanosized magnetic materials is an elegant way to bridge the gap between heterogeneous and homogeneous catalysis. The introduction of magnetic nanoparticles in a variety of solid matrices allows the combination of well-known procedures for catalyst heterogenization with techniques for magnetic separation.
1,303 citations
References
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TL;DR: Preliminary in‐vivo experiments reveal enhanced blood stability of the nanoparticles, which, coupled with sustained release of anti‐tumor agents, show good potential for cancer treatment.
Abstract: In recent decades, significant advances in drug-delivery systems have enabled more effective drug administration. To deliver drugs to specific organs, a range of organic systems (e.g., micelles, liposomes, and polymeric nanoparticles) have been designed. They suffer from limitations, including poor thermal and chemical stability, and rapid elimination by the immune system. In contrast, silica particles offer a biocompatible, stable, and “stealthy” alternative. Bioactive molecules can be easily encapsulated within silica particles by combining sol-gel polymerization with either spray-drying or emulsion chemistry. Spray-drying faces challenges, including low yield, surface segregation, and size limitations. In contrast, sol-gel emulsions enable the production of nanoparticles with homogeneous drug distribution, and permit ambient temperature processing, necessary for handling biologicals. Independent control of the size and release rate can be readily achieved. Preliminary in-vivo experiments reveal enhanced blood stability of the nanoparticles, which, coupled with sustained release of anti-tumor agents, show good potential for cancer treatment.
846 citations
TL;DR: In this paper, organic modification with aminopropyl group of two MCM-41 materials having different pore sizes (obtained from trimethylalkylammonium surfactants with different chain sizes (16 and 12 carbon atoms)) has been carried out in order to control the delivery rate of ibuprofen from the siliceous matrix.
Abstract: Organic modification with aminopropyl group of two MCM-41 materials having different pore sizes (obtained from trimethylalkylammonium surfactants with different chain sizes (16 and 12 carbon atoms)) has been carried out in order to control the delivery rate of ibuprofen from the siliceous matrix. This functionalization was performed by two different methods: the as-synthesized MCM-41 sample was treated with aminopropyltrimethoxysilane (method a), and the MCM-41 was first calcined and then funtionalized by reaction with aminopropyltrimethoxysilane (method b). The amount of ibuprofen adsorbed from hexane solution is lower for the C12 derived materials. A slower delivery rate has been observed for method b, whereas a minor influence of the pore size on the delivery rate has been found.
608 citations
235 citations
TL;DR: In this article, a uniform spindle-type particles of iron coated with silica were obtained by reduction of precursor hematite cores covered with the silica shell in hydrogen atmosphere at elevated temperatures.
211 citations
TL;DR: In this article, the effect of the carboxylic acid nature on the size of the magnetic particles was examined, and various steps in the synthesis and functionalization, as well as the nature, size, and location of the particles into the final solids were studied by means of IR and XRD, bulk magnetic measurements, Mossbauer, BET, and TEM techniques.
Abstract: Chemisorption of propionic acid vapors by an iron impregnated MCM-41 porous silica leads to the formation of iron−propionate species that upon pyrolysis can be transformed into γ-Fe2O3 nanoparticles of uniform size (∼150 A) and homogeneously dispersed on the external surfaces of the porous silica support. The effect of the carboxylic acid nature on the size of the magnetic particles was examined. The magnetically modified MCM-41 solid retains its crystallinity and large surface area and can be functionalized with various organosilicon ligands, e.g., (CH3O)3SiCH2CH2CH2NHCH2CH2NH2, to produce novel reconstructed MCM-41 derivatives without destroying the magnetic properties of the parent material. The various steps in the synthesis and functionalization, as well as the nature, size, and location of the particles into the final solids were studied by means of IR and XRD, bulk magnetic measurements, Mossbauer, BET, and TEM techniques.
83 citations