A transparent oxygen sensor array

Oxygen plays a crucial role in the proper functioning of tissues, yet many questions remain about the distribution and consumption of oxygen in tissue layers. Previous methods to measure oxygen have not provided enough information to relate the overall oxygen distribution in the tissue to changes in the tissue microvasculature. This thesis describes a new tool for oxygen measurement, a transparent oxygen sensor array. It is an array of independent surface sensors on a transparent substrate fabricated using semiconductor processing techniques. This new sensor array has several advantages over previous sensing techniques. The semiconductor techniques allow the sensor array design to be independent of the fabrication methods. The number of sensors, their size and spacing can all be specified to provide the best measurement for any given microcirculatory structures. The transparent substrate allows tissue visualization during sensor placement and operation making precise array positioning possible. Most importantly, changes in the microvasculature can be correlated with changes in the oxygen distribution by simultaneous video recording through the microscope and oxygen measurement by the sensors.;Sensor arrays were constructed and tested extensively in vitro to determine sensor array response to oxygen, sensor stability and sensor transient response. Results show that the sensor has a linear response to oxygen and is stable over several days operation. Experimental simulations of an oxygen concentration gradient demonstrate the ability of the sensor array to measure oxygen gradients.;Initial feasibility tests were done to demonstrate sensor array performance under conditions of intended use. The sensor array was used to measure oxygen concentrations on the surface of the rat cremaster preparation. The sensor array was able to measure the initial drop in tissue oxygen when the tissue layer was sealed off from the atmosphere. Changes in the tissue oxygen concentration were made with the sensor array following the fall and rise of tissue oxygen. The sensor array was also able to detect a gradient in oxygen concentration on the tissue surface. The sensor array proved stable throughout the length of the tissue experiment. The transparent oxygen sensor array is ready for further application in the measurement of tissue oxygen.