Events Calendar

Lyman Handy Colloquium

Speaker: Professor David Kisailus, University of California - Riverside

Talk Title: Structure and Composition Analysis of an Ultra-hard Magnetic Biomineral in Chiton Radular Teeth

Abstract: Through the course of evolution, nature has evolved efficient strategies to synthesize inorganic materials that demonstrate desirable mechanical properties. These biological systems demonstrate the ability to control nano- and microstructural features that significantly improve mechanical properties of otherwise brittle materials. The fully-mineralized radular teeth of chitons is one of such example of a superior biomineral consisting of a brittle, magnetic iron oxide crystal. Chitons are a group of herbivorous marine mollusks that have evolved ultra-hard and damage-tolerant teeth to graze upon algae growing on and within rocky substrates. Our results from nano-indentation analyses of the teeth of chiton (Cryptochiton stelleri), indicated that it retained largest hardness and stiffness properties of any biomineral. In order to understand the relationship between composition, structure and mechanical properties of the fully mineralized radular teeth, we further conducted detailed structural and compositional analyses of this magnetic biomineral using various microscopy and spectroscopy techniques. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses revealed the rod-like orientation of the magnetite crystallites in the teeth. Furthermore, chitin, a polysaccharide found in the exocuticles of many insects, was detected from the teeth by infrared and raman spectroscopic analyses. We believe that the combination of this organic matrix and hard mineral, constructed in a unique microstructure, yields a damage-tolerant, ultra-hard, magnetic biomineral.

Host: Professor Nutt

More Info: http://chems.usc.edu/academics/colloquia.htm

Location: James H. Zumberge Hall Of Science (ZHS) - 159

Audiences: Everyone Is Invited

Contact: Petra Pearce

Event Link: http://chems.usc.edu/academics/colloquia.htm