A computer-supported oxystat system maintaining steady-state O2 partial pressures and simultaneously monitoring O2 uptake in biological systems

Abstract

A feedback-controlled oxystat system is described maintaiing steady-state O2 partial pressures (pO2) between 0.01 mmHg (14 nM-O2) and 150 mmHg (210 .mu.M-O2) and sitmulateously monitoring O2 uptake at rates between 0.1 and 120 .mu.M-O2 .cntdot. min-1 in suspensions of cells, in subcellular fractions and in solutions of enzymes. At pO2 value between 0.2 and 150 mmhg (0.28 and 210 .mu.M-O2) a polarographic O2 sensor was used, and below a pO2 of 0.2 mmHg (0.28 .mu.M-O2) the O2-dependent luminescence of the photobacterium Vibrio fischeri was utilized to monitor the actual pO2. At a selected pO2, O2 supply is maintained by injecting appropriate amounts of O2-saturated aqueous medium into the raction chamber by using a motor-driven burette. The oxystat system is under control of a computer that reads the O2 sensors, interacts with the motor-driven burette, calculates the O2 uptake from the amounts of O2-saturated medium added, collects data from further measuring devices and provides the documentation of the results during incubation.