title: Enzyme activity control by responsive redoxpolymers.
abstract: A new thermoresponsive poly-N-isopropylacrylamide (PNIPAM)-ferrocene polymer was synthesized and characterized. PNIPAMFoxy bears additional oxirane groups which were used for attachment by a self-assembly process on a cysteamine-modified gold electrode to create a thin hydrophilic film. The new redox polymer enabled electrical communication between the cofactor pyrrolinoquinoline quinone (PQQ) of soluble glucose dehydrogenase (sGDH) and the electrode for sensitive detection of this enzyme as a prospective protein label. The temperature influence on the redox polymer/enzyme complex was investigated. An inverse temperature response behavior of surface bound PNIPAMFoxy compared to the soluble polymer was found and is discussed in detail. The highest efficiency of mediated electron transfer for the immobilized PNIPAMFoxy with sGDH was observed at 24 degrees C, which was twice as high as that of its soluble counterpart. A steady-state electrooxidation current densitiy of 4.5 microA.cm-2 was observed in the presence of 10 nM sGDH and 5 mM glucose. A detection limit of 0.5 nM of soluble PQQ-sGDH was obtained.
authors.affiliation: Fraunhofer Institute for Biomedical Engineering, Potsdam, Germany. Martin.Katterle@ibm
authors.forename: Birgit
authors.initials: B
authors.lastname: Nagel
authors.forename: Axel
authors.initials: A
authors.lastname: Warsinke
authors.forename: Martin
authors.initials: M
authors.lastname: Katterle
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D004795:Enzyme Stability; D005296:Ferrous Compounds / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry*; D005949:Glucose Oxidase; D006046:Gold / Q000737:chemistry*; D006358:Hot Temperature; D000075163:Metallocenes; D010084:Oxidation-Reduction
chemical_list: D000180:Acrylic Resins; D005296:Ferrous Compounds; D000075163:Metallocenes; C052970:poly-N-isopropylacrylamide; D006046:Gold; D005949:Glucose Oxidase; D005947:Glucose; C004998:ferrocene