ABSTRACT
Carbon nanotubes (CNTs) have attracted a great deal of interest due to the unique combination of their one-dimensional (1D) molecular symmetries and physicochemical properties. 1 Among the many potential applications, 1,2 CNTs have become promising functional materials for the development of advanced biosensors with novel features. It has been demonstrated that CNTs could promote electron transfer with various redox active proteins, ranging from glucose oxidase (GOx) 3,4 with a deeply embedded redox center to cytochrome c (Cyt-c) 5,6 and horseradish peroxidase (HRP) 7,8 with surface redox centers. For the use of CNTs in biosensing applications, however, it is essential to immobilize biomolecules on the CNT structure without diminishing their bioactivity. Therefore, a number of intriguing approaches have been devised for functionalization of CNTs with various biomolecules, 9–15 such as DNA, proteins, and enzymes, either on their sidewalls or at the endcaps. 16–20
