ABSTRACT
Ever since the emergence of photosynthesis and subsequent appearance of eukaryotic organisms, oxygen and life have been connected through a complicated interdependence. The use of oxygen as substrate for energy production, albeit very efficient, is not without risk. In cell-based microfluidic applications in particular, the oxygen concentration of a sample stream itself represents a parameter with significant effect on cellular development and function. This chapter demonstrates that thin-film optical oxygen sensors fabrication, calibration, and use for spatially resolved measurement of DO2 in microfluidic devices related to the control of cellular microenvironments. Traditional laboratory procedures for the measurement of oxygen in solution require the extraction of a sample volume for external analysis. This sampling approach is limited by the difficulty and time needed for extraction and analysis. Two main technologies, amperometric electrochemical and optical sensing, currently constitute the bulk of integrated sensors for the measurement of DO2 in biological applications.
