News

October 29, 2019
Graduation of Master’s students
September 27, 2019
On Bees and Humans
[...]
Weltoffene Hochschulen gegen Fremdenfeindlichkeit
  • Show english version,
  • Show german version,

Politi Group - Home

Chitin based biological materials and biomineralization


After cellulose chitin is the second most abundant natural biomacromolecule. It forms all arthropod cuticles, the cell walls of fungi and also is produced by molluscs, various protozoans and algae. We focus on the arthropod cuticle, in which α-chitin crystalline nano-fibrils embedded in a protein matrix are the basic building unit of the material.

Currently, the main objectives of our research is to obtain basic understanding of the cuticular material on the one hand and to gain insight into the structure-function relations in specific functional organs such as cuticular tools and mechanosensors, on the other hand;

Basic understanding of the cuticular material at the molecular level: We study the chitin-protein interaction, the cuticle interaction with water and the properties of the matrix in terms of composition, for example metal ions and halogen incorporation or mineralization in crustaceans, and their effect on cuticle properties.

Structure function relation: We aim at establishing direct correlation between organ morphology and chitin fiber arrangement, in terms of microstructure, fiber alignment and orientation and the spatial arrangement of different microstructural motifs within a functional organ/tool.

Mechano-sensing in spiders: the spider cuticle is covered by numerous cuticular-sensors that react with remarkable sensitivity and specificity to a wide range of mechanical stimuli (medium flow, substrate vibration and cuticule strain). Filtering of back-ground noise from relevant information occurs at the material/organ level which makes these structures appealing as models for the bio-inspired design of mechanoresponsive and adaptive nanostructured materials.

Methodology: We use a variety of methods and analytical techniques; a large part of our work is on synchrotron based research. We use small and wide angle x-ray scattering, as well as x-ray absorption spectroscopy and EXAFS analysis. In addition we use TEM and SEM, FTIR, Raman and EELS spectroscopy. For mechanical characterization we use nanoindentaion, AFM and scanning acoustic microscopy.