Functionalization of Nitrogen-Doped Carbon Nanotubes by 1-Pyrenebutyric Acid and Its Application for Biosensing

The homogeneous nanocomposites of 1-pyrene butyric acid modified nitrogen-doped carbon nanotubes (PBA/NCNTs) are synthesized for the immobilization of enzymes and glucose biosensing. Through the aqueous carbodiimide coupling chemistry, glucose oxidase (GOD) is covalently immobilized on the surface of the as-prepared PBA/NCNTs with high enzyme loading (1.986 nmol.cm(-2)). Fast direct electron transfer between GOD and the electrode is observed with the electron transfer rate constant (ks) of 2.43 s(-1). Besides, the GOD/PBA/NCNTs-based biosensor exhibits a linear response to glucose concentrations ranging from 2 mu M to 0.2 mM with the detection limit of 1.33 mu M and the high sensitivity of 179.76 mu A.mM(-1) . cm(-2). Furthermore, this biosensor is also applied to detect glucose in the human serum samples with high accuracy. These results demonstrate that the PBA/NCNTs nanocomposites can be a promising platform for immobilizing biomolecules and biosensing application.