Paper Number
BB25 

Session
Biomaterials and Biofluid Dynamics

Title
Slime for defense – biophysical design principles in a marine environment

Presentation Date and Time
October 22, 2019 (Tuesday) 4:10

Track / Room
Track 6 / Room 306B

Authors (Click on name to view author profile)

  1. Rementzi, Katerina (FORTH, Institute of Electronic Structure & Laser)
  2. Boeni, Lukas J. (ETH Zurich)
  3. Fischer, Peter (ETH Zurich, IFNH)
  4. Vlassopoulos, Dimitris (FORTH, Institute of Electronic Structure & Laser)

Author and Affiliation Lines (in printed abstract book)
Katerina Rementzi1, Lukas J. Boeni2, Peter Fischer2, and Dimitris Vlassopoulos1
1Institute of Electronic Structure & Laser, FORTH, Heraklion 70013, Greece; 2IFNH, ETH Zurich, Zurich 8092, Switzerland

Speaker / Presenter 
Fischer, Peter

Text of Abstract
Hagfish are genetically one of the oldest living creatures on earth. Neither charming in appearance or their task they nevertheless brought their defense mechanism up to perfection during the last 150 million years. When attacked by predators, hagfish excrete a concentrated mucin – protein fiber solution, which forms within milliseconds a large body of slime. Although the slime consists out of vast amounts of water, the diluted mucin and fibers span a cohesive network eventually clogging mouth or gills of the predators and enabling the hagfish to escape. Here, we present both the rheological properties of the slime in defense and escape situations as well as the biophysical principles of slime formation in the saline marine environment [1, 2]. We show that the different rheological responses of the slime under shear and elongational flow lead to strain hardening under attack but shear thinning during escape, promoting the survival chances of the hagfish. Considering the slime as a complex polyelectrolyte, a fine-tuned interaction with the different ions present in seawater must be given to employ the full defense capability of the slime, i.e. the rapid unraveling and network formation of both mucins and skeins under charge screening conditions [3, 4]. By elucidating the molecular and biophysical design principles and their consequences on the rheological properties of the slime, we are able to provide guidelines for tailoring mechanical properties of other mucin-like polyelectrolyte systems.

[1] Böni LJ, Fischer P, Böcker L, Kuster S, Rühs PA: Sci. Rep. 6 (2016) 30371
[2] Böni LJ, Sanchez-Ferrer A, Widmer M, Biviano MD, Mezzenga R, Windhab EJ, Dagastine RR, Fischer P: ACS Appl. Mater. Interfaces 10 (2018) 40460-40473
[3] Böni LJ, Zurflüh R, Widmer M, Fischer P, Windhab EJ, Rühs PA, Kuster S: Biology Open 6 (2017) 1115-1122
[4] Rementzi K, Böni LJ, Fischer P, Vlassopoulos D: Soft Matter, submitted