Radioluminescent Light Source for Optical Oxygen Sensors

Abstract

A self-powered radioluminescent (RL) light source is evaluated as a means of supplying incident radiation for optical chemical sensors. The light source consists of 147 Pm (a -emitting radionuclide) and ZnS:Ag phosphor. Blue light (450 nm) is produced following the excitation of ZnS:Ag from particles released by the 147 Pm. The utility of this source is judged by evaluating the analytical performance of optical oxygen sensors, where the blue light from the RL source excites a ruthenium complex immobilized in a plasticized PVC or silicon membrane. Analytical information is acquired by measuring the magnitude of oxygen-induced fluorescence quenching of the ruthenium complex. The resulting RL oxygen sensors show good stability and reversibility, with detection limits of 0.25 Torr in gaseous samples and 0.028 ppm in aqueous samples. Although the RL light source is not as bright as conventional electrical-powered sources, RL sources offer the advantages of compact size, simple configuration, low power consumption, and essentially no photobleaching of the oxygen-sensitive indicator dye. In addition, different phosphors are available to provide a variety of emission wavelengths and band-passes over a wide spectral range.

Long‐term continuous monitoring of dissolved oxygen in cell culture medium for perfused bioreactors using optical oxygen sensors

“…Most of the optical oxygen sensors use optical fibers as the probe tip and blue light emitting diodes (LED) as the light sources (Gouin et al, 1997;Krihak and Shahriari, 1996;Liao et al, 1997;Lippitsch, 1988;Moreno-Bondi, 1990;Papkovsky, 1991;Preninger et al, 1994;Toba, 1999;Walt, 1998;Weigl et al, 1994). Some investigators have used glass capillaries (Chuang and Arnold, 1997, 1998, 1999Kieslinger et al, 1997) and radioluminescent (RL) light sources (Chuang and Arnold, 1997, 1998, 1999 for optical oxygen sensors. This RL source sensor is very similar to other oxygen optodes except that, the excitation light source is by a RL light source and the sensing dye is coated inside a glass capillary.…”

Monitoring and Controlling the Dissolved Oxygen (DO) Concentration within the High Aspect Ratio Vessel (HARV)

“…The sensing portion of the DO probe was prepared by the sequential application of two casting solutions onto glass disks. The first casting solution was prepared from 0.3 mL of 1 mM tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) chloride in methylene chloride (7), 0.15 g of optically transparent acetic acid releasing silicone prepolymer (Dow Corning, Midland, MI), and 0.025 g of titanium dioxide powder (99.9% pure, diameter < 5 µm; Aldrich Chemical Co., Milwaukee, WI). This casting solution was used to coat glass disks and allowed to cure for 24 h. A second casting solution, prepared from 0.01 g of carbon black (Fisher Chemical, Fairlawn, NJ), 0.12 g of silicone prepolymer, and 0.25 mL of toluene (Fisher Chemical, Fairlawn, NJ), was used to coat the first layer and allowed to cure for 24 h. This second layer protects the first layer from loss of chemical components and shields the [Ru(dpp) 3 ] 2+ complexes from exposure to outside light.…”

Technological progresses in monoclonal antibody production systems

“…187 Additionally, a spectrophotometric method based on a colorimetric technique 188 can be used, which has a sensitivity lower than the amperometric method but still higher than needed for cell culture. 10 Another alternative is the use of oxygen sensors based on fluorescent quenching of suitable dyes, 189,190 which show good stability and reversibility. 10 Actually, optical sensors have been developed for the measurement of oxygen levels in culture.…”