Highly Chemiluminescent Graphene Oxide Hybrids Bifunctionalized by <i>N</i>-(Aminobutyl)-<i>N</i>-(Ethylisoluminol)/Horseradish Peroxidase and Sensitive Sensing of Hydrogen Peroxide

Abstract

N-aminobutyl-N-ethylisoluminol and horseradish peroxidase bifunctionalized graphene oxide hybrids (ABEI-GO@HRP) were prepared through a facile and green strategy for the first time. The hybrids exhibited excellent chemiluminescence (CL) activity over a wide range of pH from 6.1 to 13.0 when reacted with H2O2, whereas ABEI functionalized GO had no CL emission at neutral pH and showed more than 2 orders of magnitude lower CL intensity than ABEI-GO@HRP at pH 13.0. Such strong CL emission from ABEI-GO@HRP was probably due to that HRP and GO facilitated the formation of O2(•-), - CO4(•2-), HO(•), and π-C═C(•) in the CL reaction, and GO as a reaction interface promoted the electron transfer of the radical-involved reaction. By virtue of ABEI-GO@HRP as a platform, an ultrasensitive, selective, and reagentless CL sensor was developed for H2O2 detection. The CL sensor exhibited a detection limit of 47 fM at physiological pH, which was more than 2 orders of magnitude lower than previously reported methods. This work reveals that bifunctionalization of GO by ABEI and HRP leads to excellent CL feature and enzyme selectivity, which can be used as an ideal platform for developing novel analytical methods.