Publications by authors named "Christoph Janzen"

Controlling and understanding the electrochemical properties of electroactive polymeric colloids is a highly topical but still a rather unexplored field of research. This is especially true when considering more complex particle architectures like stimuli-responsive microgels, which would entail different kinetic constraints for charge transport within one particle. We synthesize and electrochemically address dual stimuli responsive core-shell microgels, where the temperature-responsiveness modulates not only the internal structure, but also the microgel electroactivity both on an internal and on a global scale.

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Article Synopsis
  • Scattering-type scanning near-field optical microscopy (SNOM) provides a new approach to examining material properties, such as strain in crystals, at the nanoscale.
  • The paper introduces a SNOM setup using a novel tunable broadband laser that enables optical analysis of gallium nitride (GaN) crystal structures at nanometer scales by exciting phonon resonance.
  • The methodology allows for 2D visualization of stress-induced deviations in the GaN structure and quantifies stress levels through complex near-field spectra, demonstrating the technology's capability in analyzing crystal relaxation at nanometer resolution.
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The use of bioengineered nerve guides as alternatives for autologous nerve transplantation (ANT) is a promising strategy for the repair of peripheral nerve defects. In the present investigation, we present a collagen-based micro-structured nerve guide (Perimaix) for the repair of 2 cm rat sciatic nerve defects. Perimaix is an open-porous biodegradable nerve guide containing continuous, longitudinally orientated channels for orientated nerve growth.

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Multiphoton microscopy is a promising technique to detect spatially and temporally resolved concentration gradients of chemical compounds, e.g., reactants in hydrogel-encapsulated biocatalysts.

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