Research article Review of the potential of a wireless MEMS microsystem for biomedical applications A. Arshak Department of Physics, University of Limerick, Plassey Technological Park, Limerick, Ireland K. Arshak and G. Lyons Department of Electronic and Computer Engineering, University of Limerick, Plassey Technological Park, Limerick, Ireland D. Waldron Mid Western Regional Hospital, Limerick, Ireland D. Morris Department of Physics, University of Limerick, Plassey Technological Park, Limerick, Ireland, and O. Korostynska and E. Jafer Department of Electronic and Computer Engineering, University of Limerick, Plassey Technological Park, Limerick, Ireland Abstract Purpose – Telemetry capsules have existed since the 1950s and were used to measure temperature, pH or pressure inside the gastrointestinal (GI) tract. It was hoped that these capsules would replace invasive techniques in the diagnosis of function disorders in the GI tract. However, problems such as signal loss and uncertainty of the pills position limited their use in a clinical setting. In this paper, a review of the capabilities of microelectromechanical systems (MEMS) for the fabrication of a wireless pressure sensor microsystem is presented. Design/methodology/approach – The circuit requirements and methods of data transfer are examined. The available fabrication methods for MEMS sensors are also discussed and examples of wireless sensors are given. Finally, the drawbacks of using this technology are examined. Findings – MEMS for use in wireless monitoring of pressure in the GI tract have been investigated. It has been shown that capacitive pressure sensors are particularly suitable for this purpose. Sensors fabricated for wireless continuous monitoring of pressure have been reviewed. Great progress, especially using surface micromachining, has been made in recent years. However, despite these advances, some challenges remain. Originality/value – Provides a review of the capabilities of MEMS. Keywords Sensors, Medical equipment Paper type General review Introduction Radio telemetry pills, for use in the gastrointestinal (GI) tract, have existed since the 1950s and were called endoradiosondes, radio pills or sometimes, “gutnick”, as they appeared in 1957, the year sputnik was launched (Nebeker, 2002). The radio pill usually contains a sensor, the associated electronics and a radio transmitter. It is small enough to be swallowed and capable of operating inside the GI tract. The pills were principally designed to transmit information on temperature, pressure and pH (Mackay, 1957; Noller, 1960; Zworykin, 1957). It was hoped that these capsules would provide information to aid in the diagnosis of disorders in the GI tract. It was of particular interest to measure pressure changes inside the small bowel and large intestine as a way of understanding the underlying cause of motility disorders. However, very little useful information could be gathered. The pill was allowed to move freely through the digestive tract and as a result, the The Emerald Research Register for this journal is available at www.emeraldinsight.com/researchregister The current issue and full text archive of this journal is available at www.emeraldinsight.com/0260-2288.htm Sensor Review 25/4 (2005) 277–286 Emerald Group Publishing Limited [ISSN 0260-2288] This work was supported by Enterprise Ireland Commercialisation Fund 2003, under technology development phase, as part of the MIAPS project, reference no. CFTD/03/425. Funding was also received from the Irish Research Council for Science, Engineering and Technology: funded by the National Development Plan. This is an updated version of a paper first published in “Medical Engineering & Physics”, Vol. 27 No. 5, pp. 347-56, Arshak et al. “Review of the potential of a wireless MEMS and TFT microsystems for the measurement of pressure in the GI tract”. q 2005 with permission from Elsevier (www.sciencedirect.com/science/ journal/13504533). 277 Downloaded by National University of Ireland Galway At 07:03 30 April 2016 (PT)