In situ fiber-optic oxygen consumption measurements from a working mouse heart

Luminescence-based imaging-fiber oxygen sensors (IFOSs) were utilized for t he in situ measurement of oxygen consumption from intact perfused mouse hea rts. IFOSs were fabricated using a technically expedient, photoinitiated po lymerization reaction whereby an oxygen-sensitive polymer matrix was immobi lized in a precise location on an imaging fiber's distal face. The oxygen-s ensing layer used in this work comprised a transition metal complex, Ru(Ph( 2)phen)(3)(2+), entrapped in a gas-permeable photopolymerizable siloxane me mbrane (PS802). The transduction mechanism was based upon the oxygen collis ional quenching of the ruthenium complex luminescence; detection was perfor med utilizing an epi-fluorescence microscope/charge coupled device imaging system. IFOS measurements from working mouse hearts were validated through concurrent, blind, ex situ blood gas analyzer (BGA) measurements, The EGA a nd IFOS methodologies were utilized successfully to measure oxygen concentr ations in aortic and pulmonary artery perfusates from the working mouse hea rt before and after isoproterenol administration. Coupled with coronary-flo w measurements, these data were used to calculate myocardial oxygen consump tion. Regression analysis of measurements of myocardial oxygen consumption showed that there was a strong correlation between the values generated by the EGA sampling and those obtained via in situ IFOS methods. To our knowle dge, this research represents the first report of in situ fiber-optic senso r monitoring of oxygen content from the intact, beating mouse heart.