Effects of water on molecular and supramolecular structure and mechanical properties of fibrous protein materials

• Applicant: Admir Masic, Ph.D.
• Subject Area: Biomaterials ; Biological and Biomimetic Chemistry ; Biophysics
• Term: from 2013 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 243675033

Biological structural materials (BMs), such as collagen, silk, or bone show outstanding mechanical performance mainly due to the optimization of their structure and interactions on many levels of hierarchy (ranging from the molecular up to macroscopic length scales). It is well known that water plays a crucial role in stabilizing secondary and tertiary structure of BMs and has huge effect on the final mechanical properties (strength, toughness, elasticity etc.) of their natural and biomimetic materials. Furthermore, extraordinary forces per molecule were observed by solely dehydrating, for example collagen based rat tail tendon (forces per molecule around 20 times those observed for myosin). The mechanism behind this force generation is completely unclear. The main goal of this project is, therefore, to understand the relationship between the level of hydration and biological structure and properties at the molecular and supramolecular scale and correlate these features to the force generation and generally the macroscopic performance of BMs. In order to assess material at various length scales we plan to combine in situ synchrotron X-ray and polarized Raman scattering in controlled environmental conditions (temperature, humidity and force). To provide reliable quantitative information, characterization methods and external stimuli (mechanical and thermal) will be employed simultaneously in situ. Such a setup will be assembled and validated in the framework of the project and provide a unique experimental capability in Germany and beyond. To support experimental outcomes and to model molecular and supramolecular behavior in relation to water-induced force generation and mechanical performance, state-of-the-art molecular dynamics simulations will also be carried out. Concepts distilled from the study of natural materials will be used as guidelines in optimizing current biomimetic strategies to produce synthetic materials with mechanical performance comparable to their natural analogues. Using reconstituted and recombinant precursors, synthetic fibers and films will be produced using electro-spinning and molecular self-assembly techniques. The ultimate goal of this project is to adapt the lessons learned from investigating structure-function relationships in BMs for the development of new design and production strategies for biomimetic and biomedical applications.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1420: Biomimetic Materials Research: Functionality by Hierarchical Structuring of Materials
• International Connection: United Kingdom, USA
• Participating Persons: Professor Dr. Markus Buehler; Professor Dr. Fritz Vollrath