In vivo and in vitro evaluation of specially designed old and carbon fiber oxygen microelectrodes for living tissues

This work contributes to the development of a minimally invasive combined perfusion and oxygen sensor devoted To measurements in tissues. A novel design is reported for the oxygen sensor: glass encased microelectrodes made with gold or carbon fibers. Several designs are presented, evaluated and optimized. Their performances are compared through long term in vitro experiments. The twig carbon fiber probe design seems to Improve stability and reproducibility. In vivo experiments performed on rat liver showed that the microelectrodes can detect local tissue oxygen fluctuations. The measurement depends on the tissue location and the physiological state of the rat. The improved performance of these new designs is hypothesized to come from the minimally invasive tips of the microelectrodes (diameters between 20 and 100 mu m) which cause less tissue damage. (C) 1997 Elsevier Science S.A.