Microscale Mechanical Responses and Properties in Bio-Relevant Materials: Glioblastoma and Self-Assembled Polymer Capsules
- Event time: 1:00pm
- Event date: 1st December 2003
- Speaker: Vernita Gordon (University of Edinburgh)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
Understanding mechanical responses and properties on size scales of microns and below are essential to characterizing a variety of systems, including structures of biological relevance; such systems may have heterogeneous response over small scales within a larger bulk material or may consist of small discrete structures. Mechanical responses on these small size scales are often not amenable to probing using traditional techniques for mechanical characterization of bulk material properties. We therefore require the development of characterization techniques which are well-adapted to these materials and size scales. I will discuss investigations of two systems where microscale mechanics are essential: the human brain cancer glioblastoma and self-assembled polymer capsules. We use particle tracking and microscopy techniques to evaluate a glioblastoma tumor system growing in a 3D in vitro gel matrix; we estimate the forces and pressures exerted by this system and show mechanical remodeling of the fibers of the in vitro extra-cellular matrix environment, which may indicate a guidance mechanism for invading cells. We evaluate the mechanical responses and structures of self-assembled polymer capsules using microcantilevered deformation and a series of finite element models in combination with additional tests; these results demonstrate that these capsules consist of a polymer membrane stabilized by adsorption to colloidal particles and inflated by osmotic pressure from internal free polyelectrolyte. The interactions of this polyelectrolyte with its solution environment may be exploited to deflate and collapse these capsules, providing a non-mechanical trigger for release of capsule contents.
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..