Carbon nanotubes (CNTs) have received considerable attention in the last years due to their unique electronic, mechanical and chemical properties. A major problem to manipulate CNTs is their insolubility or poor solubility in common solvents. Therefore, the selection of the conditions for a proper solubility or dispersion of CNTs is a critical point in the development of sensors.
This work reports the performance of glassy carbon electrodes (GCE) modified by deposition of multi-walled carbon nanotubes (MWCNT) dispersed in polyethylenimine (PEI) and polylysine (Plys). In both cases, even when MWCNT are distributed in the whole electrode surface, there are regions with different conductivity. GCE modified with MWCNT dispersed in PEI (GCE/PEI-CNT) or in Plys (GCE/Plys-CNT) showed an excellent electrocatalytic activity toward different bioanalytes like ascorbic acid (AA), dopamine (Do), hydrogen peroxide, dopac, amitrol and phenolic compounds. The adsorption of single and double stranded DNA at GCE/PEI-MWCNT as well as the selective determination of Do in the presence of large excess of AA and serotonin was also studied.
The MWCNT-PEI or MWCNT-Plys layers immobilized on glassy carbon electrodes were used as a platform for building supramolecular architectures based on the self-assembling of polyelectrolytes without any pretreatment of the electrode surface, or derivatization of the carbon nanotubes, just taking advantage of the polycationic nature of the polymer used for dispersing the nanotubes. In this case we report the self-assemblying of glucose oxidase (GOx) to develop a supramolecular multistructure for glucose biosensing.
