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Nm Gold Nanoparticles (nm + gold_nanoparticle)
Selected AbstractsBiological Sensor Platforms: Photoluminescence Detection of Biomolecules by Antibody-Functionalized Diatom Biosilica (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 6 2009Mater. Microscopic shells of single-celled algae called diatoms possess intricate nanoscale features composed of photoluminescent biosilica. On page 926, the functionalization of the 10 µm centric diatom Cyclotella (center image) with the antibody Immunoglobulin G, and its use as a biosensor for immunocomplex formation are reported by D. K. Gale et al. Such formation is visible across the entire biosilica surface using FITC-labeled antigen (green image) and antigen labeled with 10 nm gold nanoparticles (top image). [source] pH-Dependent Assembly of DNA,Gold Nanoparticles Based on the i-Motif: A Switchable Device with the Potential of a NanomachineHELVETICA CHIMICA ACTA, Issue 9 2006Frank Seela Abstract The pH-dependent self-assembling of gold nanoparticles is described. Oligonucleotides containing four or six consecutive dC residues are immobilized on 15-nm gold nanoparticles. Their assembly is based on the formation of a DNA i-motif as determined by the color change from red to blue between pH,5.5 and 6.5. The process occurs within a narrow pH range and is reversible. The i-motif is formed by the antiparallel intercalation of two parallel duplexes provided by two different gold nanoparticles. This assembly process can be utilized to generate novel systems for colorimetric sensing, applications in medical imaging and therapy, and for the construction of a proton-driven nanomachine. [source] Modular, self-assembling peptide linkers for stable and regenerable carbon nanotube biosensor interfaces,JOURNAL OF MOLECULAR RECOGNITION, Issue 4 2006Mark R. Contarino Abstract As part of an effort to develop nanoelectronic sensors for biological targets, we tested the potential to incorporate coiled coils as metallized, self-assembling, site-specific molecular linkers on carbon nanotubes (CNTs). Based on a previously conceived modular anchor-probe approach, a system was designed in which hydrophobic residues (valines and leucines) form the interface between the two helical peptide components. Charged residues (glutamates and arginines) on the borders of the hydrophobic interface increase peptide solubility, and provide stability and specificity for anchor-probe assembly. Two histidine residues oriented on the exposed hydrophilic exterior of each peptide were included as chelating sites for metal ions such as cobalt. Cysteines were incorporated at the peptide termini for oriented, thiol-mediated coupling to surface plasmon resonance (SPR) biosensor surfaces, gold nanoparticles or CNT substrates. The two peptides were produced by solid phase peptide synthesis using Fmoc chemistry: an acidic 42-residue peptide E42C, and its counterpart in the heterodimer, a basic 39-residue peptide R39C. The ability of E42C and R39C to bind cobalt was demonstrated by immobilized metal affinity chromatography and isothermal titration calorimetry. SPR biosensor kinetic analysis of dimer assembly revealed apparent sub-nanomolar affinities in buffers with and without 1,mM CoCl2 using two different reference surfaces. For device-oriented CNT immobilization, R39C was covalently anchored to CNT tips via a C-terminal cysteine residue. Scanning electron microscopy was used to visualize the assembly of probe peptide (E42C) N-terminally labeled with 15,nm gold nanoparticles, when added to the R39C-CNT surface. The results obtained open the way to develop CNT tip-directed recognition surfaces, using recombinant and chemically synthesized chimeras containing binding epitopes fused to the E42C sequence domain. Copyright © 2006 John Wiley & Sons, Ltd. [source] Shuttling Gold Nanoparticles into Tumoral Cells with an Amphipathic Proline-Rich PeptideCHEMBIOCHEM, Issue 6 2009Sílvia Pujals Abstract Golden bullets: The amphipathic proline-rich cell-penetrating peptide sweet arrow peptide (SAP) is able to transport 12 nm gold nanoparticles efficiently into HeLa cells, as observed by three microscopy techniques: transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM) and transmission X-ray microscopy (TXM). Multiconjugation to such nanoparticles may provide a convenient method for unifying the key drug properties of high activity, capacity to home onto targets and delivery to therapeutic places of action. Cell-penetrating peptides (CPPs) are a potential tool for intracellular delivery of different kinds of cargoes. Because of their growing use in nanobiomedicine, both for diagnostics and for treatment, metal nanoparticles are an interesting cargo for CPPs. Here, gold nanoparticles (AuNps) and the amphipathic proline-rich peptide SAP have been used. Conjugation of the peptide onto the AuNps was achieved by addition of a cysteine to the SAP sequence for thiol chemisorption on gold, and the attachment was confirmed by visible spectroscopy, dynamic light scattering (DLS), ,-potential (ZP), stability towards ionic strength (as high as 1,M NaCl), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HR-TEM) coupled to electron energy loss spectroscopy (EELS). AuNp-C-SAP internalization in HeLa cells was observed by three different microscopy techniques,TEM, confocal laser scanning microscopy (CLSM) and transmission X-ray microscopy (TXM),and all of them have confirmed the effective intracellular delivery of AuNps by SAP. [source] | ||||||||||