Influence of phospholipidic microenvironment on the performance of a polypyrrole enzyme electrode.

ABSTRACT

Enzyme loaded phosphatidylcholine vesicles have been introduced as a new component in the design of sensing layers for the direct coating of an amperometric transducer. For this purpose, choline oxidase was chosen as a model enzyme, and the resulting vesicles were mixed with an amphiphilic pyrrole derivative [12-(pyrrol-1-yl)dodecyltriethylammonium tetrafluoroborate]. A minute amount of this mixture was deposited and dried on a platinum electrode, then electropolymerized. Compared to a similar preparation omitting phospholipid, the sensitivity of the enzyme electrode increased from 0.06 to 0.85 mA .1. mol(-1). The response, obtained in less than 20 sec, was linearly related to the choline concentration within a broader range, extending from 2.5. 10(-7) to 3. 10(-5)M.