Micro-mechanics and Structure-function relationships in spider mechano-sensors; a key to understanding organ- performance

• Applicant: Professorin Yael Politi, Ph.D.
• Subject Area: Synthesis and Properties of Functional Materials
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 340613815

A fundamental attribute of living organisms is their ability to monitor different environmental signals and preferentially react to them. The abundance of natural sensory systems found in living organisms may serve as an inspiration and as a guide for the development of systemic sensory systems and materials; for this, an in depth understanding of the sensory mechanisms at the sensor-material level is required. The mechano-sensors of arthropods include sound, touch, medium flow and surface vibrations sensors of particular interest - allowing the interpretation of complex spatial and temporal environmental signals with little processing by the central nervous system. Spider mechanosensors exhibit remarkable sensitivity and typically operate at an extremely low stimuli threshold level. Individual mechanosensors are highly selective for a particular range of stimulus frequencies along with effective filtering of biologically non-relevant perturbation. Arrays of mechano-sensors act as compound-sensory organs and provide a high degree of spatial and directional resolution. Most of the work so far has dealt with the macro- and microscopic mechno-sensory functionalities of the sensory organs, while very limited attention has been given to their material-level structural and mechanical characteristics. The main hypothesis of this study is that the specific spatial arrangement of the basic biocomposite architecture (i.e. chitin fibers and proteins), the compositional gradients in the material forming the sensory organs, and importantly, the cuticle around them, play crucial roles in their mechano-sensory functionalities. We suggest that the sensitivity and specificity of the spider mechano-sensors stem not only from their local morphology and their spatial arrangement as a compound organ, but also from their underlying micro- and nanostructural arrangement. Thus, in order to elucidate the fundamental principles found in natural mechanoreceptors we propose here to investigate spider mechano-sensory systems, the slit organ and sensory hairs, characterize them on the material-level in terms of their hierarchical structural organization, compositional gradients and micro- and nano-mechanical properties, and integrating them into multi-scale physical models, from the material-level up to the organ level. This will allow us to identify the material-level mechanisms for the detection, transmission and filtration of the mechanical stimuli.

• DFG Programme: Research Grants
• International Connection: Austria, Israel
• Cooperation Partners: Professor Dr. Friedrich G. Barth; Luca Bertinetti, Ph.D.; Privatdozent Roland Brunner, Ph.D.; Professor Dr. Peter Fratzl; Dr. Igor Zlotnikov
• International Co-Applicant: Professor Benny Bar-On, Ph.D.