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Biological Sensing (biological + sensing)
Selected AbstractsDendrimer-Functionalized Iron Oxide Nanoparticles for Specific Targeting and Imaging of Cancer Cells,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2007H. Wang Abstract We demonstrated a unique approach that combines a layer-by-layer (LbL) self-assembly method with dendrimer chemistry to functionalize Fe3O4 nanoparticles (NPs) for specific targeting and imaging of cancer cells. In this approach, positively charged Fe3O4 NPs (8.4,nm in diameter) synthesized by controlled co-precipitation of FeII and FeIII ions were modified with a bilayer composed of polystyrene sulfonate sodium salt and folic acid (FA)- and fluorescein isothiocyanate (FI)-functionalized poly(amidoamine) dendrimers of generation 5 (G5.NH2 -FI-FA) through electrostatic LbL assembly, followed by an acetylation reaction to neutralize the remaining surface amine groups of G5 dendrimers. Combined flow cytometry, confocal microscopy, transmission electron microscopy, and magnetic resonance imaging studies show that Fe3O4/PSS/G5.NHAc-FI-FA NPs can specifically target cancer cells overexpressing FA receptors. The present approach to functionalizing Fe3O4 NPs opens a new avenue to fabricating various NPs for numerous biological sensing and therapeutic applications. [source] Formation of Gold and Silver Nanoparticle Arrays and Thin Shells on Mesostructured Silica Nanofibers,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2007S. Zhang Abstract Mesostructured silica nanofibers synthesized in high yields with cetyltrimethylammonium bromide as the structure-directing agent in HBr solutions are used as templates for the assembly of Au and Ag nanoparticles and the formation of thin Au shells along the fiber axis. Presynthesized spherical Au and Ag nanoparticles are adsorbed in varying amounts onto the silica nanofibers through bifunctional linking molecules. Nonspherical Au nanoparticles with sharp tips are synthesized on the nanofibers through a seed-mediated growth approach. The number density of nonspherical Au nanoparticles is controlled by varying the amount of seeded nanofibers relative to the amount of supplied Au precursor. This seed-mediated growth is further used to form continuous Au shells around the silica nanofibers. Both the Au- and Ag-nanoparticle/silica-nanofiber hybrid nanostructures and silica/Au core/shell fibers exhibit extinction spectra that are distinct from the spectra of Au and Ag nanoparticles in solution, indicating the presence of new surface plasmon resonance modes in the silica/Au core/shell fibers and surface plasmon coupling between closely spaced metal nanoparticles assembled on silica nanofibers. Spherical Au- and Ag-nanoparticle/silica-nanofiber hybrid nanostructures are further used as substrates for surface-enhanced Raman spectroscopy, and the enhancement factors of the Raman signals obtained on the Ag-nanoparticle/silica-nanofiber hybrid nanostructures are 2,×,105 for 4-mercaptobenzoic acid and 4-mercaptophenol and 7,×,107 for rhodamine,B isothiocyanate. These hybrid nanostructures are therefore potentially useful for ultrasensitive chemical and biological sensing by using molecular vibrational signatures. [source] On optimization of bio-probesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 6 2004N. L. Pedersen Abstract The present paper deals with the modelling and optimization of small bio-probes that can be used for biological sensing; the bio-probes can be classified as MicroElectroMechnical Systems (MEMS). The objective is to optimize the structure of the bio-probes in order to maximize the sensing sensitivity. A biological coating results in a prestress on the sensing cantilever when certain molecules are present in the surrounding medium. The mechanical deformation due to the biological material is modelled by applying a prestress in the top layer of the bio-probes. Topology optimization is used to improve the design. In the present work it is necessary to use an interpolation scheme different from the SIMP (power law) approach which is usually used in topology optimization. In calculating the sensitivities, needed for the optimization, complications due to the prestress occur, but also due to the coupling between the elastic field and the electric field which both must be used in an integrated model. These complications are dealt with and analytically obtained sensitivities are presented. Copyright © 2004 John Wiley & Sons, Ltd. [source] Applications of Nanoparticles in Biology,ADVANCED MATERIALS, Issue 22 2008Mrinmoy De Abstract The wide variety of core materials available, coupled with tunable surface properties, make nanoparticles an excellent platform for a broad range of biological and biomedical applications. This Review provides an introduction to nanoparticle,biomolecular interactions as well as recent applications of nanoparticles in biological sensing, delivery, and imaging of live cells and tissues. [source] Formation of Polyelectrolyte Multilayer Films at Interfaces Between Thermotropic Liquid Crystals and Aqueous Phases,ADVANCED MATERIALS, Issue 7 2006A. Lockwood Preparation of polyelectrolyte multilayer (PEM) films at fluid interfaces between aqueous solutions and liquid crystals is described. The orientation of the liquid crystals is coupled to the presence and organization of the PEM films (see figure). The PEM films can selectively mediate the interactions between solutes and the interfaces of the liquid crystals. PEM films offer a general method to tailor the interfacial properties of liquid crystals for chemical or biological sensing. [source] | ||||||||||