Detection of oxygen consumption of cultured adherent cells by bead injection spectroscopy

This paper describes a method for detecting oxygen consumption of adherent cell cultures. The sensing is based on oxygen-dependent quenching of the ph osphorescence of a Pt-porphyrin complex immobilized on microcarrier beads, which are used as the cell culture substrate. Bead injection, a recent vari ant of the flow injection technique, is used to pack an aliquot of the bead s into a small sensing layer that can be easily and rapidly renewed. The te chnique is tested on a model system of Chinese Hamster Ovary M1 cells grown on Cytodex-3 microcarrier beads. Cellular respiration is monitored through O-2 consumption measured across a period of 3 min. The method is validated by detecting the impairment of aerobic metabolism caused by 1.5 mM amobarb ital, Further, it is shown to have enough precision to distinguish even mor e subtle changes, such as the increase in oxygen consumption caused by stim ulation of the muscarinic ml receptor with 100 mu M carbachol.