Ionic and Molecular Transport Inside Carbon Nanotubes: Towards the Detection of Individual Biomolecules
Résumé
Biological nano-channels expressed in living cells, where they ensure keyphysiological functions, feature outstanding efficiency in terms of both ionselectivity and conductivity. The latter generally exceeds, by 3 to 4 orderof magnitude, the values expected from classical hydrodynamics. This propertyof biological nano-channels may result from their pore width in the rangeof the Debye length (0.3-30 nm) and this currently grounds many researchworks aimed at developing the use of solid-state porous nano-materials for‘‘high-throughput’’ molecular and ion sensing or sorting, with applicationssuch as drug delivery, energy conversion, water desalination and others. Singlewalled carbon nanotubes (SWNTs), which make nano-pores with welldefinedstructural and physical properties, may allow us to overcomingmany limitations of other nano-materials. The possibility of transportingions and molecules through these SWNTs has already been reported by othergroups (Lee et al., 2010, Science 329:1320; Liu et al., 2010, Science 327:64).In this context, we aim at studying the usableness of SWNT-incorporating devicesfor discriminating ions and single small biomolecules, using nucleotidesand amino acids as model compounds. Here, we will present the first part ofthis work, which consists in the fabrication of microfluidic devices incorporatingindividual SWNTs and the study of ion transport inside these devicesusing ionic current measurements, i.e. patch-clamp type. A study of the selectivityof these SWNTs will be also shown using different cations-basedelectrolytes.