Development of Optical Fibre Sensors for Online pH Monitoring in Microbioreactors

The development of non-invasive optical fibre sensor array for on-line monitoring of pH in microbioreactors is described. The working principle is based on the optical absorption of phenol red contained in culture medium. Different from other devices of the similar working principle, the proposed device requires less liquid volume (less than 0.8 mul), is non-invasive, and particularly can be configured as an array. The computer simulation and experimental results revealed that the design of oval detection chamber can substantially reduce the response time. Also, the system was proved to be able to detect pH change (pH 6.8-7.8) experienced in normal cell culture.