@phdthesis{Suetterlin2013,
  author    = {S{\"u}tterlin, Martin},
  title     = {New inverse hydogel opals as protein responsive sensors},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-70179},
  school      = {Universit{\"a}t Potsdam},
  year      = {2013},
  abstract  = {In this work, the development of temperature- and protein-responsive sensor materials based on biocompatible, inverse hydrogel opals (IHOs) is presented. With these materials, large biomolecules can be specifically recognised and the binding event visualised. The preparation of the IHOs was performed with a template process, for which monodisperse silica particles were vertically deposited onto glass slides as the first step. The obtained colloidal crystals with a thickness of 5 μm displayed opalescent reflections because of the uniform alignment of the colloids. As a second step, the template was embedded in a matrix consisting of biocompatible, thermoresponsive hydrogels. The comonomers were selected from the family of oligo(ethylene glycol)methacrylates. The monomer solution was injected into a polymerisation mould, which contained the colloidal crystals as a template. The space in-between the template particles was filled with the monomer solution and the hydrogel was cured via UV-polymerisation. The particles were chemically etched, which resulted in a porous inner structure. The uniform alignment of the pores and therefore the opalescent reflection were maintained, so these system were denoted as inverse hydrogel opals. A pore diameter of several hundred nanometres as well as interconnections between the pores should facilitate a diffusion of bigger (bio)molecules, which was always a challenge in the presented systems until now. The copolymer composition was chosen to result in a hydrogel collapse over 35 °C. All hydrogels showed pronounced swelling in water below the critical temperature. The incorporation of a reactive monomer with hydroxyl groups ensured a potential coupling group for the introduction of recognition units for analytes, e.g. proteins. As a test system, biotin as a recognition unit for avidin was coupled to the IHO via polymer-analogous Steglich esterification. The amount of accessible biotin was quantified with a colorimetric binding assay. When avidin was added to the biotinylated IHO, the wavelength of the opalescent reflection was significantly shifted and therefore the binding event was visualised. This effect is based on the change in swelling behaviour of the hydrogel after binding of the hydrophilic avidin, which is amplified by the thermoresponsive nature of the hydrogel. A swelling or shrinking of the pores induces a change in distance of the crystal planes, which are responsible for the colour of the reflection. With these findings, the possibility of creating sensor materials or additional biomolecules in the size range of avidin is given.},
  language  = {en}
}
@article{CouturierWischerhoffBerninetal.2016,
  author    = {Couturier, Jean-Philippe and Wischerhoff, Erik and Bernin, Robert and Hettrich, Cornelia and Koetz, Joachim and Sutterlin, Martin and Tiersch, Brigitte and Laschewsky, Andre},
  title     = {Thermoresponsive Polymers and Inverse Opal Hydrogels for the Detection of Diols},
  series = {Langmuir},
  volume    = {32},
  journal   = {Langmuir},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0743-7463},
  doi       = {10.1021/acs.langmuir.6b00803},
  pages     = {4333 -- 4345},
  year      = {2016},
  abstract  = {Responsive inverse opal hydrogels functionalized by boroxole moieties were synthesized and explored as sensor platforms for various low molar mass as well as polymeric diols and polyols, including saccharides, glycopolymers and catechols, by exploiting the diol induced modulation of their structural color. The underlying thermoresponsive water-soluble copolymers and hydrogels exhibit a coil-to-globule or volume phase transition, respectively, of the LCST-type. They were prepared from oligoethylene oxide methacrylate (macro)monomers and functionalized via copolymerization to bear benzoboroxole moieties. The resulting copolymers represent weak polyacids, which can bind specifically to diols within an appropriate pH window. Due to the resulting modulation of the overall hydrophilicity of the systems and the consequent shift of their phase transition temperature, the usefulness of such systems for indicating the presence of catechols, saccharides, and glycopolymers was studied, exploiting the diol/polyol induced shifts of the soluble polymers' cloud point, or the induced changes of the hydrogels' swelling. In particular, the increased acidity of benzoboroxoles compared to standard phenylboronic acids allowed performing the studies in PBS buffer (phosphate buffered saline) at the physiologically relevant pH of 7.4. The inverse opals constructed of these thermo- and analyte-responsive hydrogels enabled following the binding of specific diols by the induced shift of the optical stop band. Their highly porous structure enabled the facile and specific optical detection of not only low molar mass but also of high molar mass diol/polyol analytes such as glycopolymers. Accordingly, such thermoresponsive inverse opal systems functionalized with recognition units represent attractive and promising platforms for the facile sensing of even rather big analytes by simple optical means, or even by the bare eye.},
  language  = {en}
}
@article{CouturierSuetterlinLaschewskyetal.2015,
  author    = {Couturier, Jean-Philippe and S{\"u}tterlin, Martin and Laschewsky, Andr{\´e} and Hettrich, Cornelia and Wischerhoff, Erik},
  title     = {Responsive Inverse Opal Hydrogels for the Sensing of Macromolecules},
  series = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition},
  volume    = {54},
  journal   = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition},
  number    = {22},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1433-7851},
  doi       = {10.1002/anie.201500674},
  pages     = {6641 -- 6644},
  year      = {2015},
  abstract  = {Dual responsive inverse opal hydrogels were designed as autonomous sensor systems for (bio)macromolecules, exploiting the analyte-induced modulation of the opal's structural color. The systems that are based on oligo(ethylene glycol) macromonomers additionally incorporate comonomers with various recognition units. They combine a coil-to-globule collapse transition of the LCST type with sensitivity of the transition temperature toward molecular recognition processes. This enables the specific detection of macromolecular analytes, such as glycopolymers and proteins, by simple optical methods. While the inverse opal structure assists the effective diffusion even of large analytes into the photonic crystal, the stimulus responsiveness gives rise to strong shifts of the optical Bragg peak of more than 100nm upon analyte binding at a given temperature. The systems' design provides a versatile platform for the development of easy-to-use, fast, and low-cost sensors for pathogens.},
  language  = {en}
}
@misc{CommingesFrascaSuetterlinetal.2014,
  author    = {Comminges, Cl{\´e}ment and Frasca, Stefano and S{\"u}tterlin, Martin and Wischerhoff, Erik and Laschewsky, Andr{\´e} and Wollenberger, Ursula},
  title     = {Surface modification with thermoresponsive polymer brushes for a switchable electrochemical sensor},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-99471},
  year      = {2014},
  abstract  = {Elaboration of switchable surfaces represents an interesting way for the development of a new generation of electrochemical sensors. In this paper, a method for growing thermoresponsive polymer brushes from a gold surface pre-modified with polyethyleneimine (PEI), subsequent layer-by-layer polyelectrolyte assembly and adsorption of a charged macroinitiator is described. We propose an easy method for monitoring the coil-to-globule phase transition of the polymer brush using an electrochemical quartz crystal microbalance with dissipation (E-QCM-D). The surface of these polymer modified electrodes shows reversible switching from the swollen to the collapsed state with temperature. As demonstrated from E-QCM-D measurements using an original signal processing method, the switch is operating in three reversible steps related to different interfacial viscosities. Moreover, it is shown that the one electron oxidation of ferrocene carboxylic acid is dramatically affected by the change from the swollen to the collapsed state of the polymer brush, showing a spectacular 86\% decrease of the charge transfer resistance between the two states.},
  language  = {en}
}