title: Assembly of myoglobin layer-by-layer films with poly(propyleneimine) dendrimer-stabilized gold nanoparticles and its application in electrochemical biosensing.
abstract: The small-sized Au nanoparticles (3 nm) were prepared by reduction of HAuCl(4) in the presence of poly(propyleneimine) (PPI) dendrimers, forming the stable PPI-Au nanoclusters in aqueous medium. The PPI-Au nanoclusters might take a kind of "core-shell" structure, in which several PPI molecules were attached on the surface of one gold nanoparticle. The PPI-Au nanoclusters in aqueous dispersions and myoglobin (Mb) in its buffers at pH 5.0 were then alternately adsorbed on the surface of pyrolytic graphite (PG) electrodes and other solid substrates, forming {PPI-Au/Mb}(n) layer-by-layer films, which was confirmed by cyclic voltammetry (CV) and quartz crystal microbalance (QCM). {PPI-Au/Mb}(n) films on PG electrodes demonstrated a pair of well-defined and quasi-reversible CV reduction-oxidation peaks for Mb heme Fe(III)/Fe(II) couple and good electrocatalytic properties toward reduction of oxygen and hydrogen peroxide. Compared with {Au/Mb}(n) multilayer films containing no dendrimers and {PAMAM/Mb}(n) films assembled by polyamidoamine (PAMAM) dendrimers and Mb but in the absence of Au nanoparticles, {PPI-Au/Mb}(n) films showed better electrochemical behaviors and catalytic performances, which may be attributed to the unique structure of PPI-Au nanoclusters and good conductivity of gold nanoparticles. This novel kind of protein multilayer films assembled with dendrimer-stabilized gold nanoparticles may provide a new and general approach to fabricate the biosensors and bioreactors based on the direct electrochemistry of proteins or enzymes.
authors.affiliation: Department of Chemistry, Beijing Normal University, Beijing 100875, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Naifei
authors.initials: N
authors.lastname: Hu
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002384:Catalysis; D050091:Dendrimers / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D009211:Myoglobin / Q000737:chemistry*; D011126:Polypropylenes / Q000737:chemistry*
chemical_list: D050091:Dendrimers; D009211:Myoglobin; D011126:Polypropylenes; C443641:poly(propyleneimine); D006046:Gold