Shark egg-case cross-link chemistry : biomimetic model of densely cross-linked collagen

• Main Author: Teh, John Wei Ming
• Other Authors: School of Materials Science and Engineering
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Materials::Biomaterials
• Online Access: http://hdl.handle.net/10356/48406
• Institution: Nanyang Technological University

Dogfish egg case is an elongated and leathery, oblong shaped vessel made up of collagenous-composite structure. Being an oviparous species, female dogfish sharks lay their eggs in the open water environment, protected only by its egg case. Despite its small size, embryos are able to be fully developed under extreme temperature changes and are resilient against most predators. The egg case is of interest because of its toughness, elasticity and its ability to simultaneously regulate the diffusional flow of small molecules and ions in and out of itself with ease. This study seeks to investigate the chemistry of dogfish egg case cross-links. Based on results obtained from Raman spectroscopy tests, Electron Dispersive X-ray (EDX) mapping and cross-link isolation on the dogfish egg case, we have found evidences that: 1) Catecholic (aromatic) side-chains were involved in cross-linking and 2) Metal ions were involved and believed to form coordinate complexes with catechols. Suggestions for dogfish egg case cross-links were thereafter proposed based on analysis from experimental results and literature.