Glutamate detection by amino functionalized tetrahedral amorphous carbon surfaces
By Emilia Kaivosoja and Noora Tujunen and Ville Jokinen and Vera Protopopova and Santtu Heinilehto and Jari Koskinen and Tomi Laurila
Published in Talanta
2015
Abstract
In this paper, a novel amperometric glutamate biosensor with glutamate oxidase (GlOx) immobilized directly on \NH2\ functionalized, platinum doped tetrahedral amorphous carbon (ta-C) film, has been successfully developed. First, we demonstrate that direct GlOx immobilization is more effective on amino-groups than on carboxyl- or hydroxyl-groups. Second, we show that anodizing and plasma treatments increase the amount of nitrogen and the proportion of protonated amino groups relative to amino groups on the aminosilane coating, which subsequently results in an increased amount of active GlOx on the surface. This effect, however, is found to be unstable due to unstable electrostatic interactions between GlOx and NH3+. We demonstrate the detection of glutamate in the concentration range of 10