Search results for "Biomaterial"
showing 10 items of 1350 documents
Programming options for nanocrystal MOS memories
2003
Nanocrystal memories represent a promising candidate for the scaling of FLASH memories. In these devices, the charge is not stored in a continuous floating gate but in a discontinuous layer composed by numerous discrete silicon quantum dots well separated one from the other.The nanocrystals of radius of few nanometers are realized by chemical vapor deposition (CVD) of silicon on the tunnel oxide of 2.8 nm of thickness. These islands have been coated with a control oxide of 7 nm formed by CVD and incorporated in Metal-Oxide-Semiconductor structure. The devices are programmed and erased by tunnelling using low voltages and fast times. In addition, the programming can be easily achieved also b…
GraftFast Surface Engineering to Improve MOF Nanoparticles Furtiveness
2018
International audience; Controlling the outer surface of nanometric metal–organic frameworks (nanoMOFs) and further understanding the in vivo effect of the coated material are crucial for the convenient biomedical applications of MOFs. However, in most studies, the surface modification protocol is often associated with significant toxicity and/or lack of selectivity. As an alternative, how the highly selective and general grafting GraftFast method leads, through a green and simple process, to the successful attachment of multifunctional biopolymers (polyethylene glycol (PEG) and hyaluronic acid) on the external surface of nanoMOFs is reported. In particular, effectively PEGylated iron trime…
Solid lipid nanoparticles from amphiphilic calixpyrroles
2016
Abstract Hypothesis Macrocyclic amphiphiles form interesting self-assembling structures, including solid lipid nanoparticles, which have potential applications in drug encapsulation. Aryl-extended calixpyrroles, which act as anion binding hosts, are expected to form solid lipid nanoparticles, even though the alkyl chains have unusual perpendicular geometry with respect to the hydrophilic head group. The preparation conditions and the alkyl chain length should affect the size and stability of the particles. Experiments Solid lipid nanoparticles of two aryl-extended calixpyrroles with resorcinol walls and either meso-dodecyl or meso-methyl alkyl chains were compared. Ethanolic solutions of th…
Nanostructured medical sutures with antibacterial properties
2014
Bacterial repellence in suture materials is a desirable property that can potentially improve the healing process by preventing infection. We describe a method for generating nanostructures at the surface of commercial sutures of different composition, and their potential for preventing biofilm formation. We show how bacteria attachment is altered in the presence of nanosized topographies and identify optimum designs for preventing it without compromising biocompatibility and applicability in terms of nanostructure robustness or tissue friction. These studies open new possibilities for flexible and cost-effective realization of topography-based antibacterial coatings for absorbable biomedic…
Size filtering effect in vertical stacks of In(Ga)As/GaAs self-assembled quantum rings
2006
3 páginas, 3 figuras.
Synthesis and characterization of highly ordered cobalt-magnetite nanocable arrays.
2006
Magnetically tunable, high-density arrays of coaxial nanocables within anodic aluminum oxide (AAO) membranes have been synthesized. The nanocables consist of magnetite nanowires surrounded by cobalt nanotube sheaths and cobalt nanowires surrounded by magnetite nanotube sheaths. These materials are a combination of separate hard (Co) and soft (Fe3O4) magnetic materials in a single nanocable structure. The combination of two or more magnetic materials in such a radial structure is seen as a very powerful tool for the future fabrication of magnetoresistive, spin-valve and ultrafast spin-injection devices with nonplanar geometries. The nanocable arrays were prepared using a supercritical-fluid …
Steric stabilization of modified nanoclays triggered by temperature.
2015
Halloysite clay nanotubes were modified through the adsorption of poly(N-isopropylacrylamide)-amine terminated (PNIPA-NH2) onto the external surface by exploiting electrostatic interactions at pH=6. In spite the amount of attached polymer is rather low (1 wt%), the properties of the nanotubes are deeply modified. The apparent specific volume and isentropic compressibilities of the hybrid nanomaterial dispersed in water evidenced the transferring of the termosensitive property from the polymer to halloysite. The hydrodynamic radius as well as the ζ-potential of the nanohybrid are consistent with the attachment of a positively charged polymer onto the negative surface of the nanotube. The col…
Hierarchical Assembly of TiO2 Nanoparticles on WS2 Nanotubes Achieved Through Multifunctional Polymeric Ligands
2007
Thefunctionalization of nanotubes is required in order to bene-fit from their outstanding properties, as any application inmaterials and devices is hindered by processing and manipu-lation difficulties. Only the attachment of appropriate chem-ical functionalities on the nanotube surface allows tailoringof the properties for the respective applications. As an ex-ample, the enhancement of the nanotube solubility is onemajor task since most pristine nanotubes are insoluble inboth water and organic solvents. Thus, the improvement ofthe solubility by chemical functionalization is an importantconcept for synthetic chemists and materials scientists. Tai-loring of the surface chemical bonds might a…
Halloysite Nanotube with Fluorinated Lumen: Non-Foaming Nanocontainer for Storage and Controlled Release of Oxygen in Aqueous Media
2014
Halloysite clay nanotubes were selectivity modified by adsorbing perfluoroalkylated anionic surfactants at the inner surface. The modified nanotubes formed kinetically stable dispersions due to the enhanced electrostatic repulsions exercised between the particles. We proved that the modified nanotubes can be used as non-foaming oxygen nanocontainers in aqueous media. The gas release from supersaturated dispersions can be controlled by external stimuli and system composition. In conclusion, we managed to put forward an easy strategy to develop smart materials from natural nanoclays, which can endow important applications like the storage and delivery of gas.
Chemical Mimicry: Hierarchical 1D TiO2@ZrO2 Core−Shell Structures Reminiscent of Sponge Spicules by the Synergistic Effect of Silicatein-α and Silint…
2011
In nature, mineralization of hard tissues occurs due to the synergistic effect of components present in the organic matrix of these tissues, with templating and catalytic effects. In Suberites domuncula, a well-studied example of the class of demosponges, silica formation is mediated and templated by an axial proteinaceous filament with silicatein-α, one of the main components. But so far, the effect of other organic constituents from the proteinaceous filament on the catalytic effect of silicatein-α has not been studied in detail. Here we describe the synthesis of core-shell TiO(2)@SiO(2) and TiO(2)@ZrO(2) nanofibers via grafting of silicatein-α onto a TiO(2) nanowire backbone followed by …