title: A spider's biological vibration filter: micromechanical characteristics of a biomaterial surface.
abstract: A strain-sensing lyriform organ (HS-10) found on all of the legs of a Central American wandering spider (Cupiennius salei) detects courtship, prey and predator vibrations transmitted by the plant on which it sits. It has been suggested that the viscoelastic properties of a cuticular pad directly adjacent to the sensory organ contribute to the organ's pronounced high-pass characteristics. Here, we investigate the micromechanical properties of the cuticular pad biomaterial in search of a deeper understanding of its impact on the function of the vibration sensor. These properties are considered to be an effective adaptation for the selective detection of signals for frequencies >40 Hz. Using surface force spectroscopy mapping we determine the elastic modulus of the pad surface over a temperature range of 15-40 °C at various loading frequencies. In the glassy state, the elastic modulus was ~100 MPa, while in the rubbery state the elastic modulus decreased to 20 MPa. These data are analyzed according to the principle of time-temperature superposition to construct a master curve that relates mechanical properties, temperature and stimulus frequencies. By estimating the loss and storage moduli vs. temperature and frequency it was possible to make a direct comparison with electrophysiology experiments, and it was found that the dissipation of energy occurs within a frequency window whose position is controlled by environmental temperatures.
authors: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors: Seth L
authors: SL
authors: Young
authors: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors: Marius
authors: M
authors: Chyasnavichyus
authors: Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany.
authors: Maxim
authors: M
authors: Erko
authors: Department of Neurobiology, University of Vienna, 1090 Vienna, Austria.
authors: Friedrich G
authors: FG
authors: Barth
authors: Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany.
authors: Peter
authors: P
authors: Fratzl
authors: Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany.
authors: Igor
authors: I
authors: Zlotnikov
authors: Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany.
authors: Yael
authors: Y
authors: Politi
authors: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA. Electronic address: vladimir@mse.gatech.edu.
authors: Vladimir V
authors: VV
authors: Tsukruk
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001696:Biomechanical Phenomena; D003460:Crystallization; D055119:Elastic Modulus; D005260:Female; D018625:Microscopy, Atomic Force; D061848:Optical Imaging; D013112:Spiders / Q000033:anatomy & histology* / Q000502:physiology* / Q000648:ultrastructure; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014732:Vibration; D014783:Viscosity
chemical_list: D001672:Biocompatible Materials
keywords: Atomic force spectroscopy; Biomechanics; Biosensor materials; Stimulus transmission; Viscoelasticity