Spy Pills

AN INGESTIBLE ELECTRONIC PILL FOR REAL TIME
ANALYTICAL MEASUREMENTS OF THE GASTRO-
INTESTINAL TRACT

Erik A. Johannessen1, Tong-Boon Tang2, Lei Wang1, Lili Cui1, Mansour
Ah mad ian2, Nizamettin Aydin2, Alexandros Astaras2, Alan F. Murray2, Brian
W. Flynn2, Tugrul Aslan2, Steve P. Beaumont3, David R. S. Cumming1 and
Jonathan M. Cooper1.
1Department of Electrical Engineering, The University of Glasgow, UK.
2Department of Electrical Engineering, The University of Edinburgh, UK.
3Institute for System Level Integration, The ALBA Centre, Livingston, UK.

Abstract
A state-of-the-art electronic "pill" has been developed for in situ studies of the gastro-
intestinal (GI) tract using integrated circuit and system level integration technologies.
The measurement parameters include real time analysis of temperature, pH, conductivity
and dissolved oxygen.

Keywords: ingestible pill, sensor array, microchip control, wireless communication

1. Introduction
Ingestible analytical microsystems have extended the application of lab-on-a-chip
devices to environments with restricted access [1]. There is now a great potential in
developing non invasive microelectronic pills capable of monitoring physiological
processes in situ for the detection of disease and abnormalities in medical research.
The device comprises 4 microelectronic sensors. A microfabricated silicon diode
measures the body core temperature whilst an ISFET sensor [2] measures local pH of
the stomach acid and the intestine. A pair of direct contact gold electrodes measures the
conductivity of, and indirectly, the contents of the stomach. The fourth sensor consists
of a three-electrode electrochemical cell [3], which is used to detect the level of
dissolved oxygen and to identify the activity of aerobic bacteria in the small and large
intestine. All the sensors are controlled by an application specific integrated circuit
(ASIC), which sample the data at a resolution of 8 bit prior to... [continues]

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