Oxygen sensor for use in the brain

by Paul, David W.; Prajapati, Indira

Low level brain oxygen is directly assocd. with stroke, and monitoring oxygen is essential to investigations of mechanisms in the brain that alter oxygen uptake. The Clark-type sensor is popular in measuring the current from the electrochem. redn. of dissolved oxygen at a noble metal cathode. The problem in using an electrochem. sensor is that they are easily fouled by the large proteins present in the brain which alters the oxygen sensitivity. Dr.Paul's lab has reported use of electro-polymd. eugenol as a protective coating for electrodes reducing oxygen; Bovine Serum Albumin (BSA) served as the electrode fouling agent.The electrode film was electropolymd. by electropolymn. process which was carried out by cyclic voltammetry with 40 sweep segments from 0.0V to 0.7V using 0.31mL Eugenol in 200mL of 0.1 M NaOH soln. onto 2.0 mm Au electrode. The oxygen calibration curves were done with and without the electropolymd. electrode. It was obsd. that the oxygen sensitivity was dropped when the bare sensor was used in BSA. However, after the eugenol coated gold electrode was eletropolymd. the oxygen sensitivity was regained. Therefore, the eugenol can protect the gold electrode from fouling environments, while allowing O2 to pass through the coating. This result is believed to help in the development of electrochem. sensors for brain oxygen.