title: Adsorption of enzymes to stimuli-responsive polymer brushes: Influence of brush conformation on adsorbed amount and biocatalytic activity.
abstract: Polyelectrolyte brushes can be utilized to immobilize enzymes on macroscopic surfaces. This report investigates the influence of the pH value of the surrounding medium on the amount and the activity of enzymes adsorbed to poly(2-vinylpyridine) and poly(acrylic acid) brushes, as well as the creation of thermoresponsive biocatalytically active coatings via the adsorption of enzymes onto a mixed brush consisting of a polyelectrolyte and temperature-sensitive poly(N-isopropylacryl amide). Spectroscopic ellipsometry and attenuated total reflection-Fourier transform infrared spectroscopy are used to monitor the adsorption process. Additionally, infrared spectra are evaluated in terms of the secondary structure of the enzymes. Glucose oxidase is used as a model enzyme, where the enzymatic activity is measured after different adsorption conditions. Poly(acrylic acid) brushes generally adsorb larger amounts of enzyme, while less glucose oxidase is found on poly(2-vinylpyridine), which however exhibits higher specific activity. This difference in activity could be attributed to a difference in secondary structure of the adsorbed enzyme. For glucose oxidase adsorbed to mixed brushes, switching of enzymatic activity between an active state at 20°C and a less active state at 40°C as compared to the free enzyme in solution is observed. However, this switching is strongly depending on pH in mixed brushes of poly(acrylic acid) and poly(N-isopropylacryl amide) due to interactions between the polymers.
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany; Department of Physical Chemistry of Polymer Materials, Technische Universität Dresden, 01062 Dresden, Germany; Institute of Functional Interfaces, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Meike
authors.initials: M
authors.lastname: Koenig
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Bittrich
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany.
authors.forename: Ulla
authors.initials: U
authors.lastname: König
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany; Department of Polymer Science & Engineering, Mahatma Gandhi University, Kottayam, Kerala 686 560, India.
authors.forename: Bhadra Lakshmi
authors.initials: BL
authors.lastname: Rajeev
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Müller
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany.
authors.forename: Klaus-Jochen
authors.initials: KJ
authors.lastname: Eichhorn
authors.affiliation: Department of Polymer Science & Engineering, Mahatma Gandhi University, Kottayam, Kerala 686 560, India.
authors.forename: Sabu
authors.initials: S
authors.lastname: Thomas
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany; Department of Physical Chemistry of Polymer Materials, Technische Universität Dresden, 01062 Dresden, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Stamm
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany. Electronic address: uhlmannp@ipfdd.de.
authors.forename: Petra
authors.initials: P
authors.lastname: Uhlmann
mesh_terms: D000178:Acrylamides / Q000737:chemistry* / Q000378:metabolism; D055162:Biocatalysis; D005949:Glucose Oxidase / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D011145:Polyvinyls / Q000737:chemistry* / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000178:Acrylamides; D011108:Polymers; D011145:Polyvinyls; C058671:poly(2-vinylpyridine); D005949:Glucose Oxidase
keywords: Biocatalysis; Enzymes; Polymer brushes; Protein adsorption; Responsive coatings