UTS has set out to become an international centre of expertise in scanning probe microscopy. The instruments available include: a Dimension 3100 atomic force microscope; a Multimode scanning probe microscope with low current head, capable of resolving individual molecules under suitable conditions; a near-field scanning optical microscope (NSOM) and an Easyscan STM. The equipment is accessed by a broad user community in UTS and beyond. The samples examined may be divided - somewhat arbitrarily - between biological and inorganic systems.
 I-V curves taken through a self-assembled monolayer of XYL molecules on gold |
Wet biological samples are best examined using our wet cell, and this methodology has been applied to the difficult problem of imaging the surfaces of cells, lipid layers and liposomes. The ultimate objective of this is to resolve the structure of protein ion channels inserted within them. This challenge has been taken on by Dr Stella Valenzuela and Mr Mark Berkahn.
In the more conventional dry mode, huge strides in resolution and capability have been made, particularly since Dr Hadi Zareie joined the Institute from University of Washington, USA. Zareie, Cortie, Ford, McDonagh and Liu amongst others, have been working together to develop a fundamental understanding of the electrical properties of self-assembled monolayers (SAMs), while Maaroof and Berkahn have concentrated on exploiting these instruments to provide information on the morphology of various metallic and inorganic systems. SAMs of traditional and more exotic molecules have been produced and characterised, and a semi-empirical numerical model for a gold-SAM-Au-air double tunnel barrier has been developed by Cortie and Ford.
 Morphology of the p-xylyenedithiol (XYL) monolayers. (A,B) Molecules assembled for 48 hours from 1 mM solutions lie parallel with the gold surface. (C,D) Molecules assembled for 24 hours from less concentrated (0.5 nM) solution are orientated perpendicularly to the surface |
