Over The Horizon

Coming Into Focus

A recent visit by a US expert has given researchers in New Zealand a glimpse of the power of atomic force microscopy (AFM). Professor Ratneshwar Lal of the University of California, Santa Barbara, demonstrated some of the interesting applications of the technique, which enables the imaging of the three-dimensional surface structure of biological specimens at resolutions approaching molecular level.

AFM combines the photographic quality of images from the relatively low resolution scanning electron microscope with the high resolution of the transmission electron microscope. The advent of the light microscope revolutionised the biological sciences. The later invention of the electron microscope and its commercial inception in the 1950s revealed much of the fine structural detail of cellular components. AFM has potential to go a step further by providing molecular resolution under specific imaging environments.

One group interested in the new development was the Wool Research Organisation of New Zealand, which sees AFM as providing a chance to take a closer look at wool structure.

Dr Warren Bryson is particularly enthusiastic about the prospect of seeing the shape of wool keratin molecules. His primary research interest is the "cell membrane complex", an 11-layered region responsible for intercellular adhesion. Proteins and lipids in this region play a key role in the rate of carpet wear, with intercellular proteins cementing the cells together similar to the way mortar holds bricks together, and the structure being reinforced further by transmembrane proteins which are analogous to flexible reinforcing rods in concrete.

The AFM microscope can reveal the structure and intermolecular relationships of these key proteins. Ultimately, developments in sheep genetics and breeding may enable the production of wool with high-strength cell interactions which can lead to improved abrasion resistance in wool products.

During the visit, arrangements were made with Lal for a post-doctoral WRONZ Fellow to work with him for a couple of years in Santa Barbara.

"In addition to solving the mysteries of the cell membrane complex, the WRONZ Fellow will be working in a laboratory at the leading edge of research into the micro-world of sub-cellular structures and biomolecules, and will be in a position to obtain exciting new information on the ultra-structure and chemical composition of the wool fibre," says Bryson.