Overview of Research

This group has extensive experience and expertise in the design, fabrication and characterisation of a wide range of sensors and related devices (bio-sensing, electrophysiological monitoring, pacing, defibrillation and wound healing). The group has major strengths in the areas of AC impedance/dielectric spectroscopy, cyclic voltammetry and potentiometry and in their use in the characterisation of materials, interfaces and devices. Work is carried out on modeling of the linear and non-linear electrical properties of electrode-electrolyte interfaces (eg platinum, iridium, Ag/AgCl) and materials (eg biological tissues, membranes, surface coatings).

Key Projects

Impedance and dielectric measurements can be used to study and characterise the electrical properties of materials and their interfaces. Such data can in turn be used to furnish information on the homogeneity, thickness and integrity of layers, the roughness and quality of interfaces and on reactions, such as corrosion, taking place at interfaces. At NIBEC suitable measurement cells have been designed and constructed and AC impedance devices adapted and used successfully to study the integrity and surface topography of deposited coating layers and the electrical properties of human tissue in vivo. Electrical Impedance Spectroscopy (EIS) is now the accepted technique for both determining corrosion rates and identifying corrosion reaction mechanisms due to its ability to detect interfacial relaxations covering a wide range of frequencies and thus distinguish the different corrosion processes taking place. These advances are due to the development of suitable FRA instruments, theoretical models and appropriate software, all of which are available at NIBEC. Such mathematical/equivalent circuit models of interface processes tend to be based on assumptions of the properties of local reactions, the distribution of these properties over the interface and of the effects of surface topography. For example, film integrity at the early stages of growth can be correlated with process parameters thus enabling their accurate modeling and the identification of optimum nano-scale film growth conditions. The group won the top prize of £10,000 in the 2004 competition for IMPEDIMAP, an impedance-based system for monitoring and characterising wounds. The system is presently being further developed with Proof Of Concept funding from Invest NI.

Collaboration

The group has enjoyed collaborations with various academic partners in UK, Europe and worldwide including, University College London, Kings College London, Centro Nacional de Microelectronica (Spain), University of Twente (Holland), University of Surrey, INSERM (France), Scuola Superiore Santa Anna (Italy), as evidenced by joint publications, patents and products. Currently collaborations are ongoing with Dublin City University and the Royal Victoria Hospital Belfast on an All Ireland Point-of-Care Sensors project. Previous European projects have included MICROCARD and MICROTRANS. The group has close links with the Biomedical Microsensors & Microsystems group, CNRS LPM, Lyon, France.

Industrial Partners

The group is/has been involved in the successful design and development of a wide range of novel Sensing and Stimulation Bio-medical electrodes for leading companies/organisations. Much of this work has been patented and successfully transferred to industry. Astronaut-monitoring systems have been designed for several space agencies including the Anglo-Soviet JUNO space mission, the German-Soviet MIR programme and a NASA mission. One patented design is for a disposable ECG electrode presently marketed world-wide by over 10 of the top biomedical device companies. As a consequence, the group is widely recognised as world leaders in the fields of Biomedical Electrode Technology and Bio-Impedance Spectroscopy. The group has acted as consultant to several leading companies including Welch Allyn, UnoMedical, Aspect Medical, Hewlett Packard, Elan, and Laboratoires Fournier.

For further information please contact the Group Leader: Professor Eric McAdams

E: et.mcadams@ulster.ac.uk

T: +44 (0) 28 9036 8934