A simple and inexpensive method to control oxygen concentrations within physiological and neoplastic ranges

Abstract

Traditional methods for regulating oxygen concentration ([O2]) in in vitro experiments over the range found in normal and tumor tissues require the use of expensive equipment to generate controlled gas atmospheres, or the purchase of a range of gas cylinders with certified O2 percentages. Herein we describe a simple and inexpensive enzymatic method for generating low, precise steady-state [O2] levels that are stable for several hours. This method is particularly applicable to the in vitro study of some classes of hypoxia targeted antitumor prodrugs and bioreductively activated agents.

Quinone and nitrofurantoin redox cycling by recombinant cytochrome b5 reductase

“…Difference spectra were generated by subtracting the absolute oxidized spectra from the absolute reduced spectra. Where applied, anaerobic conditions in the wells were generated by incubating reaction mixtures with 25 U/mL catalase, 50 mM glucose, and 12.5 U/mL glucose oxidase for 20 min prior to initiating spectral analysis (Penketh et al , 2015).…”

Physicochemical Considerations of Tumor Selective Drug Delivery and Activity Confinement with Particular Reference to 1,2-Bis(Sulfonyl)-1- Alkylhydrazines Delivery

“…The reductively activated antibiotic nitrofurazone exhibits a K O2 that closely matches the half maximal radiation sensitizing O 2 concentration (Fig. 1B ) [ 11 ]. Radiation, coupled with a HAP with a K O2 of ~ 4 μM, could theoretically level cell kill across relevant degrees of oxygenation if its cytotoxic actions remained largely confined to the activating cells (~ 10 μm radius).…”