Spectrometer with atomic resolution

Australia has long been known for developing leading-edge scientific instrumentation and this reputation is set to continue with the development of an impedance spectrometer that is up to 1000 times more accurate than its competitors.

Impedance spectroscopy can be used to obtain structural information about molecular processes occurring at membranes and surfaces immersed in solution. The technology, with huge potential in the emerging fields of nanotechnology, biotechnology and hybrid devices, works by applying a small alternating current of known frequency to a system and then measuring the phase difference and the amplitude of the electrical potential that develops across it.

Fifteen years ago two scientists working at the University of New South Wales began developing an electric spectrometer for their own research. Now Dr Terry Chilcott and Professor Hans Coster lead a research group in the School of Chemical and Bio-Molecular Engineering at the University of Sydney and their basic concept has reached commercial reality.

The INPHAZE impedance spectrometer has already been in use throughout Australia and internationally for several years. Current users include ANSTO; the Los Almos National Laboratory (LANL); the University of NSW; the University of Technology, Sydney, as well as the University of Sydney. The LANL equipment is being used to conduct fundamental research into the dielectric and electrical conductance properties of single crystals of amino acids.

The deceptively compact device offers levels of precision an order of magnitude greater than existing impedance spectrometers and equal to or better than the significantly more expensive alternatives such as X-ray reflectometry, electron microscopy and neutron diffraction.

The INPHAZE system can be used to generate detailed information about the fine structure of layered materials and thin films down to the nanometer scale. Indeed the system is so powerful and precise that the actual arrangements of molecules and atoms can be observed.

With a phase precision of 0.0010° and an impedance magnitude resolution of 0.002% over a very wide frequency range (0.01 Hz to 100 kHz) the spectrometer will enable scientists to study chemical and biological systems with atomic resolution.

Assoc Prof Michael James from the Bragg Institute (ANSTO) explains: "Key areas for the application of this technology include the investigation of surface chemical reactions, bio-molecular processes occurring at cell membranes, and the development of biosensors. While the first two of these applications relate to our fundamental understanding of cell chemistry and biophysics, the latter area stands to enable a huge impact in the development of applied technologies for medical diagnostics and health care. Very sensitive biosensors can be constructed by the covalent attachment of organic molecules on a silicon chip. When biologically active systems such as antibodies, proteins, toxins or even viruses specifically bind to the sensing molecules, a change in the chip occurs that can be detected by impedance spectroscopy. The INPHAZE spectrometer should provide a rapid and inexpensive bio-sensing system of great versatility, as the chemistry of a vast number of these biological reactions will become better understood."

The company, INPHAZE, based at the University of Sydney and headed by Dr Ditta Bartels, was formed last year to develop and launch a range of high-resolution impedance technology-based products - starting with the INPHAZE spectrometer. The company hopes to sell twenty instruments in its first year of operation.

Financial backing to assist in the commercialisation of the spectrometer was provided by the Australian Technology Showcase and BioBusiness Program run by the NSW Department of State and Regional Development and an AusIndustry Commercialising Emerging Technologies (COMET) grant.