In biological cells and tissues environment, real-time monitoring and controlling dissolved oxygen (DO) provides critical information for studying cellular metabolism process, health status and pathological features. This paper developed an optical DO sensor based on fluorescence quenching principle, prepared tris(4,7-diphenyl-1,10- phenanthroline)ruthenium(II) dichloride complex sol-gel sensing film, and studied its sensing performance. The principle of this sensor is that dissolved oxygen has quenching effect towards the fluorescence emitted by ruthenium complex. So the fluorescence intensity is reduced due to the existence of DO. The measurement limit of DO was 10- 100%, the response time was 20s, and the resolution was 0.02. Compared to traditional dissolved oxygen electrode probe, this luminescent fiber had many advantages, such as smaller size, shorter response time and higher stability.
It is very important to monitor and control pH during cell and tissue culture. On-line pH monitoring provides valuable information on cell metabolic processes and living environment. A novel simple method to real-time measure pH during cell and tissue culture has been experimentally demonstrated using a tapered optical fiber coated with polyaniline. The fiber is tapered to produce the leaking mode in the sensing film. The absorption coefficient and the refractive index of the polyaniline film will vary with different pH values and resultantly change the optical spectral responses. The optical power droped with the increase of the pH at 1042nm. Such a device is sensitive to pH allowing the determination of pH values ranging from 5 to 11 and the resolution of the order of 0.03. Comparing to the conventional pH glass electrode, this optical measurement has smaller size, faster response and can avoid the contamination of the cell and tissue culture fluid.