Poly(benzoxazine) as an Immobilization Matrix for Miniaturized ATP and Glucose Biosensors

The reproducible immobilization of enzymes represents a key requirement in developing sensitive and fast-responding amperometric microbiosensors. A microbiosensor for the respective detection of glucose and adenosine-5'-triphosphate (ATP) is presented by using a poly(benzoxazine) derivative for the entrapment of the enzymes glucose oxidase (GOD) and hexokinase (HEX) at platinum (Pt) microelectrodes (MEs). For glucose, a sensitivity of 123.05 +/- 10.78pA/mM (n=5) was obtained, which shows twice as high sensitivity compared to microbiosensors that use electrophoretic paints as the immobilization matrix for the same size ME (radius: 25m). For the determination of ATP, a sensitivity of 48.47 +/- 5.12pA/mu M and a signal-to-noise ratio of 40 at physiological pH values were obtained. Apart from their enhanced sensitivity, a significant improvement of these sensors is related to their improved mechanical stability. The applicability of these poly(benzoxine)-based microbiosensors for ATP detection was demonstrated with measurements at receptor protein tyrosine phosphatase zeta (PTPR) osteoblastic cells during mechanical stimulation.