Abstract: We present an optical biosensor design that expands the utility of enzyme biosensors. These biosensors are fabricated by site-selective photodeposition of analyte-sensitive polymer matrices on optical imaging fibers. These dual-analyte arrays allow for the simultaneous, independent measurement of the analyte of interest and the transducing analyte. The first integrated optical-biosensors using this design have been prepared that allow both the dependent and independent analytes to be measured simultaneously, for example penicillin. and pH (Healey and Walt, 1995) or glucose and O-2 (Li and Walt, 1995). Independent measurement of the transducing analyte allows penicillin or glucose to be quantitated in the presence of a concurrent pH or O-2 change, respectively. Penicillin can be measured in the range 0.25-10.0 mM in the pH range 6.2-7.5 . Glucose can be measured in the range 0.6-20.0 mM in the O-2 range 20-100%. The utility of the sensor design was demonstrated by using the penicillin-dual-analyte biosensor to quantitate penicillin produced during a Penicillium chrysogenum fermentation. (C) 1997 Published by Elsevier Science Limited. 25 References

Abstract: An optical penicillin biosensor is described, based on the enzyme penicillinase. The sensor is fabricated by selective photodeposition of analyte-sensitive polymer matrices on optical imaging fibers. The penicillin-sensitive matrices are fabricated by immobilizing the enzyme as micrometer-sized particles in a polymer hydrogel with a covalently bound pH indicator. An array of penicillin-sensitive and pH-sensitive matrices are fabricated on the same fiber. This array allows for the simultaneous, independent measurement of pH and penicillin. Independent measurement of the two analytes allows penicillin to be quantitated in the presence of a concurrent pH change. An analysis was conducted of enzyme kinetic parameters in order to model the penicillin response of the sensor at all pH values. This analysis accounts for the varying activity of the immobilized penicillinase at different pH values. The sensor detects penicillin in the range 0.25-10.0 mM in the pH range 6.2-7.5. The sensor was used to quantify penicillin concentration produced during a Penicillium chrysogenum fermentation. (27 References)