title: Ionic topochemical tuned biosensor interface.
abstract: Two new hydrophilic, poly(ethylene glycol) (PEG)-based redox copolymers bearing electrochemically active ferrocene (Fc) and thiol/disulfide anchoring functionalities were synthesized. These copolymers are shown to adsorb on gold surfaces causing polymeric self-assembled monolayers (pSAMs) that possess triple functions: "redox-active", "ionic-tunable", and "bio-inert". Both immobilized polymers showed redox potentials at +400 mV (Ag|AgCl), and facilitate the electrocatalytical oxidation of NADH. Additionally, interfacial architecture of the polymers is affected by an increase in Ca(2+) concentration, which leads to an amplification of the electrochemical response. The electrode current, measured for NADH-oxidation, increased by 80% after addition of 10 mM Ca(2+) ions. Considering the Ca(2+) influence on the heterogeneous electron transfer a structural model of the immobilized polymers is proposed based on the strong chelating ability of noncyclic PEG moieties.
authors.affiliation: Fraunhofer Institute for Biomedical Engineering, Am Muhlenberg 13, 14476 Potsdam, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Nagel
authors.forename: Nenad
authors.initials: N
authors.lastname: Gajovic-Eichelmann
authors.forename: Frieder W
authors.initials: FW
authors.lastname: Scheller
authors.forename: Martin
authors.initials: M
authors.lastname: Katterle
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques; D005296:Ferrous Compounds / Q000737:chemistry; D000075163:Metallocenes; D011092:Polyethylene Glycols / Q000737:chemistry
chemical_list: D005296:Ferrous Compounds; D000075163:Metallocenes; D011092:Polyethylene Glycols; C004998:ferrocene