STUDY OF AN ENZYME COUPLED SYSTEM FOR THE DEVELOPMENT OF FIBER OPTICAL BILIRUBIN SENSORS

We have established an analytical procedure for bilirubin (BR) determi nation by following the variation of its yellow absorption band in the presence of the biocatalytic system haemoglobin/glucose oxidase/gluco se. The influence of the pH of the medium, the haemoglobin/hydrogen pe roxide ratio, and the concentration of the various components in the m ixture on the system activity was evaluated. The solubility of the unc onjugated BR was analysed. An anionic detergent in Tris buffer, in whi ch it presents a high critical micellar concentration, was selected fo r the BR/bovine serum albumin cleavage. The Michaelis-Menten constant of the system (after the optimisation of the various parameters) was d etermined and compared with K-m values reported in the literature for similar catalytic systems. Preliminary results obtained with the haemo globin and glucose oxidase immobilised either in poly(vinyl alcohol) o r by crosslinking with glutaraldehyde, show that this system is promis ing as a future biosensor.