title: Dendrimer-encapsulated silver nanoparticles as a novel electrochemical label for sensitive immunosensors.
abstract: This paper reports on the synthesis and characterization of a novel electrochemical label for sensitive electrochemical stripping metalloimmunoassays based on silver dendrimer-encapsulated nanoparticles (NPs). Silver dendrimer nanocomposites (Ag-DNCs) were synthesized from a generation 5-7 (G5-7) hydroxyl-terminated ethylenediamine-core-type (2-carbon core) PAMAM dendrimer. Several fixed ratios of Ag(+)/dendrimer were prepared with the aim to obtain stable nanocomposites with maximal silver loading in the interior of a polymeric shell. Synthesized Ag-DNCs were characterized by UV-vis spectrophotometry, atomic force microscopy (AFM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The G7 Ag-DNC synthesized in 2000 molar excess of silver (1/4 ratio of tertiary amine/Ag(+)) turned out a more suitable candidate for the label development. By combination of the differential pulse voltammetry (DPV) and the anodic stripping analysis (ASV) on a carbon electrode, down to 1.35 x 10(+10) of individual Ag-DNCs (LOD=0.9 pM, 25 ml volume) was detected after the dissolution of silver nanoparticles in a diluted nitric acid. The potential advantages of proposed electrochemical label are discussed.
authors.affiliation: UJEP, Faculty of Science, 40096 Usti nad Labem, Czech Republic.
authors.forename: M
authors.initials: M
authors.lastname: Stofik
authors.forename: Z
authors.initials: Z
authors.lastname: Strýhal
authors.forename: J
authors.initials: J
authors.lastname: Malý
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D050091:Dendrimers / Q000737:chemistry*; D004563:Electrochemistry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry*; D013194:Staining and Labeling / Q000379:methods
chemical_list: D020099:Coated Materials, Biocompatible; D050091:Dendrimers; D012834:Silver