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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. [ABSTRACT FROM AUTHOR]

The combinatorial method of quartz crystal microbalance coupled with spectroscopic ellipsometry can be used to follow the in situ synthesis of catalytically active palladium nanoparticles in polymer brushes in situ. By combining these two orthogonal techniques, it is possible to thoroughly characterize the thickness, composition, optical, and mechanical properties of nanoscopic thin films. [ABSTRACT FROM AUTHOR]

Novel catalytically active nanocomposite surfaces are fabricated by in situ synthesis of palladium or platinum nanoparticles inside poly(2-vinylpyridine) (P2VP) brushes, used as a nano-reactor. Focusing on the revelation of the interaction of the metal species with P2VP, the immobilization is investigated by X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform IR (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), as well as scanning electron microscopy (SEM) and transmission electron micro­scopy (TEM). Homogeneous distribution of nanoparticles is achieved. The mechanism of nanoparticle formation is investigated by study­ing the influence of particular reaction parameters and the catalytic activity of the nanocomposites is confirmed using a model reaction. [ABSTRACT FROM AUTHOR]