GRAPHENE AND CARBON NANOTUBE NANOMATERIALS IN LAYER-BY-LAYER STRUCTURED ELECTROCHEMICAL ENZYMATIC BIOSENSORS: A REVIEW

Abstract

This review highlights the recent developments made, during the past five years, from 2010 onwards, in biosensors that bring together the advantages of the layer-by-layer (LbL) methodology and the use of graphene and carbon nanotubes as carbon nanomaterials. LbL methodology in biosensor assembly has been widely used to incorporate suitable materials with controlled molecular architecture, enabling the build-up of stable and complex architectures. At the same time, the incorporation of nano-sized materials into a sensing device has been exploited in order to improve the electronic communication between the enzyme and the electrode substrate. The advantages of incorporating carbon nanomaterials (CN) into LbL multilayers for the development of biosensors with improved analytical performance are described. The key steps for the incorporation of CN in self-assembled architectures are the choice of the type of CN functionalization and pairing with an adequate oppositely charged polyelectrolyte. The preparation of the LbL assembly will be described in detail. Electrochemical and surface characterization will underline the importance of incorporating CN and identify their nanostructures and build-up in the LbL assembly. Finally, applications of CN-LbL biosensors will exemplify their utility as analytical tools for the detection of key analytes, such as glucose, ethanol, cholesterol, and neurotoxins.