Feasibility of an on-line fluorescence-based optical sensor for oxygen monitoring in cell culture media

摘要

An oxygen sensor is under development to be part of a battery of optically based sensors for future cell culture experiments to be conducted by the National Aeronautics and Space Administration (NASA). This fluorescence-based sensor is intended to be indwelling within a self-contained cell culture apparatus designed for long-term experiments typical of those performed in the space shuttle or international space station. Our probe takes advantage of a well-documented characteristic of oxygen to quench most fluorophores. In this example, a species of ruthenium dye which is known to exhibit a considerable reduction in luminescence via oxygen quenching is immobilized in a poly(ethylene glycol) (PEG) hydrogel and immobilized in aqueous media. External to the vessel that holds the sensor and the cell culture media, a single fiber delivers LED excitation light while other fibers collect the emission light and return it to a detector. The sensor has been shown in initial trials to exhibit a high correlation to secondary oxygen sensors and retains good reproducibility across a range of oxygen concentrations that are typical for cell culture experiments (0-9.1 ppm O_2 at 35°). Sensor hydrogels retain their physical shape and sensitivity to oxygen over a period of at least days.