Determination of gaseous and dissolved oxygen in a closed fat cell culture system

A novel method facilitates the determination of O2 content in the gas phase and in the culture medium of closed cell culture systems: Total O2 was swept out for 3 min by a stream of N2 under atmospheric pressure and carried to the measuring unit of a PBI Dansensor TIA-111-LV oxygen sensor, creating a peak-shaped signal, which was integrated over time. From the peak area, gas flow (determined by a Rotameter flow meter), and actual gas pressure and temperature, O2 content was calculated. The precision of the method was 1.1% (CV), recovery was 97.7%. O2 uptake was measured in white adipocytes, isolated by the collagenase method and cultured in a 3D matrix of agarose gel. As a basis of reference, DNA content of the cultures (9.5 pg/cell) was determined by a fluorimetric method. The viability of the cells was not affected by O2 determination, as shown by the maintenance of cellular adenine nucleotide content during the analytic procedure. The decline of O2 content in the cultures was constant over 72 h. The mean rate of cellular O2 consumption was 34.1 mumol/micrograms DNA.h.