From Layered Molybdic Acid to Lower-Dimensional Nanostructures by Intercalation of Amines under Ambient Conditions

Nanostructures of varied dimensionality such as rods, scrolls, and disks of molybdenum oxide have been synthesized in gram quantities under ambient conditions using exfoliation of the layers as a synthetic tool. Intercalation of alkylamines (CnH2n+2NH2, where n = 3, 4, 8, 12, and 16) into yellow molybdic acid (MoO3·2H2O) and subsequent treatment with nitric acid resulted in molybdenum oxide nanorods, nanodisks, or oxide−amine composite nanorods. The sizes of the nanoparticles range from a few nanometers to micrometers in length and 10 to 200 nm in diameter. Detailed X-ray, scanning electron microscopy, and transmission electron microscopy analyses reveal an inverse relation between the size…

Superparamagnetic γ-Fe2O3 nanoparticles with tailored functionality for protein separation

Polymer coated superparamagnetic gamma-Fe(2)O(3) nanoparticles were derivatized with a synthetic double-stranded RNA [poly(IC)], a known allosteric activator of the latent (2-5)A synthetase, to separate a single 35 kDa protein from a crude extract which cross reacted with antibodies raised against the sponge enzyme.

Multifunctional polymer-derivatized γ-Fe2O3 nanocrystals as a methodology for the biomagnetic separation of recombinant His-tagged proteins

Abstract Multifunctional polymer-derivatized superparamagnetic iron oxide (γ-Fe2O3) nanoparticles were prepared for biomagnetic separation of histidine-tagged recombinant proteins building up a faster and efficient method for protein separation by making use of their intrinsic magnetic properties. Using polymer bound γ-Fe2O3 nanocrystals, a 6× histidine-tagged recombinant protein (silicatein) with a molecular weight of 24 kDa has been isolated and purified. The supermagnetic iron oxide nanocrystals were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), SQUID and Mossbauer and the polymer functionalization of the γ-Fe2O3 nanocrystals was monitored by UV–vi…

Functionalized magnetic nanoparticles for selective targeting of cells

AbstractInitiation of pathways that lead to proliferation and chemoresistance by Toll-like receptors (TLRs) is an important factor in cancer progression. Here, we show the response of human cancer cells to TLR signaling inevitably linked to tumor biology. The approach is based on tailored multifunctional magnetic nanoparticles equipped with pathogen-derived ligands (CpG) functioning as TLR agonists (molecular component) to investigate the impact of transcription factor immune activation on human cancer cells. Magnetic nanoparticles (MnO and bifunctional Au-MnO) particles were covalently coated with a multifunctional polymer, displaying no cytotoxicity, to being able to enter cells while car…

Cell Specific Targeting of Multifunctional γ-Fe2O3 Nanoparticles Through Surface Binding of dsDNA

AbstractThe immobilization of polyinosinic-polycytidylic acid [poly(IC)] on ã-Fe2O3 maghemite nanoparticles via the phosphor-amidate route using a multifunctional polymer is reported. The dsRNA coupled nanoparticles were used to visualize the Toll-like (TLR3) receptors at the cell surface. The presence of TLR3 was demonstrated independently in the Caki-1 cell line by RT-PCR and immunostaining techniques

dsRNA-functionalized multifunctional gamma-Fe2O3 nanocrystals: a tool for targeting cell surface receptors.

CpG-DNA loaded multifunctional MnO nanoshuttles for TLR9-specific cellular cargo delivery, selective immune-activation and MRI

Initiation of pathways that lead to a proliferation and chemoresistance by Toll-like receptors (TLRs) are an important factor in cancer progression. Multifunctional magnetic nanoparticles equipped with a pathogen-derived ligand (CpG) functioning as TLR agonists were used to show the impact of immune activation on human HNSCC (head and neck squamous cell carcinoma) cells. The response of human cancer cells to TLR signaling is linked to tumor biology. The magnetic MnO nanoparticles were coated with a multifunctional polymer, displaying no cytotoxicity and being able to enter cells while carrying foreign DNA (unmethylated CpG) to recognize intracellular TLR9. Both the particle and the nucleic …

Engineered Multifunctional Nanotools for Biological Applications

Smart multifunctional magnetic nanoparticles are popular candidates for several biological applications owing to their intrinsic magnetic property and diverse applications that range from rare protein separation and biomedical utilization to cancer therapy and diagnostics. A universal protocol, for the development of such nanocarriers, is highly desirable for scientists with different backgrounds so that custom-made multifunctional nanoparticles can be developed to address their needs, among which are the superparamagnetic iron oxide and manganese oxide nanoparticles that are synthesized through high temperature decomposition reactions. However, an interface is needed to present these inorg…

Au@MnO-“Nanoblumen” - Hybrid-Nanokomposite zur selektiven dualen Funktionalisierung und Bildgebung

In j ngster Vergangenheit hat das Interesse f r die Entwicklung von Hybrid-Nanostrukturen, die sich aus verschiedenen Materialien zusammensetzen, in erheblichem Mase zugenommen. Es wurde berichtet, dass die Zusammenf hrung verschiedener Nanomaterialien, die ihrerseits spezifische optische, magnetische oder elektronische Eigenschaften aufweisen, zu Kompositen aus mehreren dieser Komponenten, deren individuelle Eigenschaften ver ndern oder sogar verbessern k nnen. Durch gezielte Optimierung der Struktur und der Grenzfl chenwechselwirkung innerhalb der Nanokomposite k nnte eine breite Basis f r zuk nftige Technologien geschaffen werden, beispielweise f r die synchrone Biomarkierung, Proteintre…

The 2′-5′-oligoadenylate synthetase in the lowest metazoa: isolation, cloning, expression and functional activity in the sponge Lubomirskia baicalensis

Aquatic animals, especially filter feeders such as sponges [phylum Porifera], are exposed to a higher viral load than terrestrial species. Until now, the antiviral defense system in the evolutionary oldest multicellular organisms, sponges, is not understood. One powerful protection of vertebrates against virus infection is mediated by the interferon (IFN)-inducible 2'-5'-oligoadenylate synthetase [(2-5)A synthetase] system. In the present study we cloned from the freshwater sponge Lubomirskia baicalensis a cDNA encoding a 314 aa long ORF with a calculated size of 35748Da, a putative (2-5)A synthetase, and raised antibodies against the recombinant protein. The native enzyme was identified in…

dsRNA-funktionalisierte γ-Fe2O3-Nanokristalle: ein Instrument zur gezielten Adressierung von Rezeptoren an der Zelloberfläche

Au@MnO nanoflowers: hybrid nanocomposites for selective dual functionalization and imaging.

Recently, the development of hybrid nanostructures consisting of various materials has attracted considerable interest. The assembly of different nanomaterials with specific optical, magnetic, or electronic properties to multicomponent composites can change and even enhance the properties of the individual constituents. Specifically tuning the structure and interface interactions within the nanocomposites has resulted in novel platforms of materials that may lead the way to various future technologies, such as synchronous biolabeling, protein separation and detection, heterogeneous catalysis, and multimodal imaging in biomedicine. Of the various kinds of nanomaterials, gold nanorods show an…

Fabrication of a Silica Coating on Magnetic γ-Fe2O3 Nanoparticles by an Immobilized Enzyme

Silicatein, a hydrolytic protein encountered in marine sponges, was immobilized on maghemite (γ-Fe2O3) nanoparticles that were surface functionalized with a reactive mulfunctional polymer. This polymer carries an anchor group based on dopamine which is capable of binding to the γ-Fe2O3 surface and a reactive functional group which allows binding of various biomolecules onto inorganic nanoparticles. This functional nitrilotriacetic acid (NTA) group allows immobilization of His-tagged silicatein on the surface of the γ-Fe2O3 nanoparticles. The surface-bound protein retains its native hydrolytic activity to catalyze formation of silica through copolymerization of alkoxysilanes Si(OR)4. Functio…

Pathogen-Mimicking MnO Nanoparticles for Selective Activation of the TLR9 Pathway and Imaging of Cancer Cells

Here, design of the first pathogen-mimicking metal oxide nanoparticles with the ability to enter cancer cells and to selectively target and activate the TLR9 pathway, and with optical and MR imaging capabilities, is reported. The immobilization of ssDNA (CpG ODN 2006) on MnO nanoparticles is performed via the phosphoramidite route using a multifunctional polymer. The multifunctional polymer used for the nanoparticle surface modification not only affords a protective organic biocompatible shell but also provides an efficient and convenient means for loading immunostimulatory oligonucleotides. Since fluorescent molecules are amenable to photodetection, a chromophore (Rhodamine) is introduced …

Functionalized Magnetic Nano-particles for Selective Targeting and Sensing of Cells

Double-stranded RNA polyinosinic-polycytidylic acid immobilized onto gamma-Fe2O3 nanoparticles by using a multifunctional polymeric linker.