Cobalt Oxide Co3O4 Nanopowder / Nanoparticles …
T1 - Synthesis and electrocatalytic property of cubic and spherical nanoparticles of cobalt platinum alloys
Multifunctional Iron Oxide Nanoparticles for …
Antibodies are proteins with special Y- shapes. They can specifically recognize and bind to antigens in both the recognition phase (cellular receptors) and during the effectors phase (synthesis and secretion) of humoral immunity. Active targeting by monoclonal antibodies (mAbs) combined with SPION is a promising technology for magnetic resonance imaging.
AB - Carbon material supported bi- or tri-metallic nanoparticles were usually used to replace noble metals, such as platinum, for improving catalytic performance and reducing the cost. In this paper, a carboxylate-functionalized multi-walled carbon nanotube supported bimetallic platinum-cobalt nanoparticles catalyst was synthesized using a simple one-step ultrasonic method. Electrochemical experiments showed that this catalyst exhibited excellent electrocatalytic activity in acid solution for the oxygen reduction reaction. In detail, the onset potential and half-wave potential of this catalyst positively shifted compared with the commercial platinum/carbon catalyst. The as-prepared catalyst also presented a high mass activity. Additionally, it showed a four-electron reduction pathway for the oxygen reduction reaction and exhibited better stability (about 82.8% current density was maintained) than platinum/carbon during the current durability test. This journal is
Wet Synthesis of Monodisperse Cobalt Oxide Nanoparticles
3. Laurent S, Forge D, Port M, Roch A, Robic C, Vander Elst L, Muller RN. Magnetic iron oxide nanoparticles: synthesis, stabilization, vectorization, physicochemical characterizations, and biological application. 2008;108:2064-110
In general, nanoparticles tend to aggregate through hydrophobic interactions or attractive van der Waals forces in an effort to minimize the surface energy. In the blood stream, such aggregates can trigger opsonization, the process by which a particle becomes covered with opsonin proteins, thereby making it more visible to the mononuclear phagocytic system (MPS), such as RES. The phagocytic mechanisms render nanoparticles ineffective as theranostic devices by removing them from the bloodstream . Therefore, evading uptake by RES and increasing the blood circulation half-life are major challenges for developing theranostic nanoparticles in clinical applications . Several methods of camouflaging nanoparticles have been developed to yield 'stealth' nanoparticles, which are invisible to MPS. These approaches interfere with the binding of opsonin proteins to the nanoparticle surfaces in support of a long circulation half-life, thereby increasing the chance that the nanoparticles can effectively target tumor sites. In order to impart stealth properties to the nanoparticles, one of the most promising molecules is the FDA-approved PEG. Natural or synthetic polymers, small organic molecules, and core-shell structures have also been utilized for nanoparticle surface coatings. However, a high surface coverage can decrease binding to and uptake by target cancer cells. This section describes the use of several coating molecules as shielding materials. The optimal surface densities of the coating materials and the targeted ligands will be discussed.
Gas phase synthesis of fcc-cobalt nanoparticles - …
5. Ge S, Shi X, Sun K, Li C, Uher C, Baker JR, Banaszak MM, Orr BG. Facile hydrothermal synthesis of iron oxide nanoparticles with tunable magnetic properties. 2009;113:13593-99
Ellington . used this bioconjugation method to conjugate an anti-EGFR aptamer onto GNPs to demonstrate the targeting specificity of a newly identified aptamer . As described above, they coated GNPs with thiol-modified capture ONTs that hybridized to an extended anti-EGFR aptamer to generate anti-EGFR aptamer-conjugated GNPs. Jon . utilized the hybridization method to conjugate an anti-PSMA-aptamer to iron oxide nanoparticle surfaces . In their study, CG-rich duplexes were constructed at the ends of the aptamers to achieve multiple Dox-binding on the nanoparticles. They immobilized amine-functionalized capture ONTs (5'NH2-A10-(TCG)7-3') on the surfaces of the carboxyl-modified iron oxide nanoparticles. Magnet purification yielded the capture ONT-coated iron oxide nanoparticles. A (CGA)7-extended anti-PSMA-aptamer was synthesized by transcription, and the aptamers were added to the ONT-coated nanoparticles to produce Apt--TCL-SPIONs. Thermal gravimetric analysis (TGA) indicated that PSMA aptamers (28,451 Da) hybridized to approximately 33% of the ONTs (9,708 Da) conjugated to the nanoparticles. aptamers capture ONTshe surface of nanoparticles via staining in larger samples (106 cells).ons [nitude highenn
Cobalt Oxide (Co3O4) Nanoparticles - Properties, Applications
Synthesis of shape-controllable cobalt nanoparticles …
Keywords: nanoparticles, iron oxide, gold, contrast agents, MRI, optical imaging, miRNA delivery, theranostics.
Microfluidic Synthesis of Cobalt Nanoparticles - …
This article discusses the properties and applications of cobalt oxide nanoparticles.
synthesis of Co 3 O 4 nanoparticles ..
Synthesis of shape-controllable cobalt nanoparticles and their shape-dependent performance in glycerol hydrogenolysis
Synthesis and Characterization of Co-Zn Ferrite Nanoparticles …
Richards-Kortum reported a novel approach to conjugating nanoparticles and aptamers . The aptamer was extended to provide a hybridization site for complementary ONT-coated nanoparticles. GNPs (20 nm) were coated with thiol-modified capture ONTs containing a hexa(ethylene glycol) spacer and a complementary sequence for the aptamer extension, and the extended anti-PSMA aptamer was hybridized to capture ONT-coated GNPs by heating the solution at 70°C for 5 min, followed by incubation at room temperature for 30 min. The resulting aptamer-GNPs showed targeted detection of LNCaP (PSMA+) cells via reflectance imaging. This conjugation strategy has several advantages. First, the negatively charged phosphate groups of the ONTs prevented aggregation of the nanoparticles through electrostatic repulsion, leading to nanoparticle stability, even in high-salt environments. Second, aptamers were easily conjugated to the surfaces of nanoparticles via complementary sequence hybridization with the capture ONTs, which preserved the aptamer integrity and stability during bioconjugation. A PEG spacer between the thiol group and the complementary capture sequence of capture ONT improved the hybridization efficiency by minimizing steric hindrance between the gold surface and the hybridization site. Third, a small number of aptamers was needed for binding to the nanoparticles through the short cheap capture ONTs, unlike thiolated aptamers, in which significant concentrations of aptamers are necessary to coat and stabilize the nanoparticles. Finally, multiplexing capabilities can be obtained by incorporating other types of molecules (targeting, delivery, imaging, or therapeutic agents) into the nanoparticles.
CCVD synthesis of carbon-encapsulated cobalt nanoparticles …
In addition to organic coatings, core-shell structures, such as biocompatible silica- or gold-covered magnetic nanoparticles, have provided an attractive approach to developing stealth nanoparticles. Silica shells serve as protective stable nanoparticle coatings under aqueous conditions. The ability to encapsulate functional molecules within the nanoparticle matrix is a unique feature of these nanostructures. Hyeon and Moon developed Fe3O4 nanocrystal-embedded, core-shell mesoporous silica nanoparticles, and they demonstrated their multifunctional application to simultaneous MR/optical imaging and drug delivery . This study suggested a precise method for controlling the size of the silica nanoparticles smaller than 100 nm. The surfactant cetyltrimethylammonium bromide (CTAB) provided an organic template for the formation of a mesoporous silica shell and stabilized the hydrophobic Fe3O4 nanocrystals in an aqueous solution. The sol-gel process occurred through the template by using tetraethylorthosilicate (TEOS) and rhodamine B isothiocyanate (RITC)-labeled aminopropyltriethoxysilane (APS), and generated amine groups containing silica shell, to which PEG was covalently conjugated via succinimidyl end group to render further biocompatibility. Dox molecules loaded onto the as-synthesized Fe3O4@mSiO2(R)-PEG NPs to convey therapeutic properties. The core-shell structure exhibited magnetic and fluorescent properties, as well as a therapeutic index, suggesting the utility of the nanostructure in biomedical theranostic applications. On the other hand, gold provides several advantages as a coating material due to its inertness and its unique ability to absorb near-IR radiation. Hyeon and Cho described magnetic gold nanoshells (Mag-GNS) consisting of gold nanoshells encapsulating magnetic Fe3O4 nanoparticles as a novel nanomedical platform for simultaneous diagnostic imaging and thermal therapy . Monodisperse 7 nm Fe3O4 nanoparticles stabilized with 2-bromo-2-methylpropionic acid (BMPA) were covalently attached to amino-modified silica spheres through a direct nucleophilic substitution reaction between the bromo groups and the amino groups. Gold seed nanoparticles were then attached to the residual amino groups of the silica spheres. Finally, a complete 15 nm thick gold shell embedded with Fe3O4 nanoparticles formed around the silica spheres to generate Mag-GNS. To target breast cancer, an anti-HER2/neu antibody was conjugated onto the surfaces of the Mag-GNS. SKBR3 breast cancer cells treated with Mag-GNS could be detected using a clinical MRI system, followed by selective destruction by near-IR radiation.
Cobalt oxide Nanoparticles /(Co3O4 Nanopowder) | …
Perez . utilized the click reaction to conjugate folate onto multifunctional iron oxide nanoparticles . They synthesized poly(acrylic acid) (PAA)-coated iron oxide nanoparticles and encapsulated lipophilic fluorescence dyes (dialkylcarbocyanine fluorophores) within the hydrophobic coating layers on the nanoparticles to provide dual imaging capabilities. The nanoparticles were functionalized with alkyne groups via a reaction with propargyl amine and EDC/NHS, followed by further reaction with azide-containing folate via the click chemistry. A hydrophobic anticancer drug, Taxol, was then encapsulated to yield multifunctional theranostic nanoparticles. A thick polymeric coating layer, 40 nm thick according to DLS measurements, played a key role in incorporating hydrophobic guest molecules. The MTT and cellular uptake assessments indicated the folate-decorated nanoparticles' specificity toward target tumor cells (A549). MRI studies demonstrated the ability of those theranostic agents to behave as sensitive MRI contrast agents.
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