This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Add to Saved Citations Download to citation manager Add to My Marked Citations Citing Articles Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Sun, Y. Articles by Greminger, M. A. Search for Related Content Social Bookmarking                   What's this?

Investigating Protein Structure Change in the Zona Pellucida with a Microrobotic System

Swiss Federal Institute of Technology, ETH Zurich, Switzerland, sun{at}iris.mavt.ethz.ch

Bradley J. Nelson

Swiss Federal Institute of Technology, ETH Zurich, Switzerland

Michael A. Greminger

University of Minnesota, Minnesota, USA

In this paper we present a microrobotic system that integrates microscope vision and microforce feedback for characterizing biomembrane mechanical properties. We describe robust visual tracking of deformable biomembrane contours using physics-based models. A multi-axis microelectromechanical systems based force sensor is used to determine applied forces on biomembranes and to develop a novel biomembrane mechanical model. By visually extracting biomembrane deformations during loading, geometry changes can be used to estimate applied forces using a biomembrane mechanical model and the determined elastic modulus. Forces on a biomembrane can be visually observed and controlled, thus creating a framework for vision and force assimilated cell manipulation. The experimental results quantitatively describe a stiffness increase seen in the mouse zona pellucida (ZP) after fertilization. Understanding this stiffness increase, referred to as "zona hardening", helps provide an understanding of ZP protein structure development, i.e., an increase in the number of cross links of protein ZP1 between ZP2 and ZP3 units that is conjectured to be responsible for zona hardening. Furthermore, the system, technique, and model presented in this paper can be applied to investigating mechanical properties of other biomembranes and other cell types, which has the potential to facilitate many biological studies, such as cell injury and recovery where biomembrane mechanical property changes need to be monitored.

Key Words: zona pellucida proteins • protein cross-linking • stiffness • microrobotic cell manipulation • microelectromechanical systems • boundary element • deformable visual tracking • vision-based force sensing

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?