Modeling of carbon nanotube-based biosensors
We are studying the properties of carbon nanotube (CNT) biosensors using numerical simulation. The research is focusing on the electronic transport through CNTs that are exposed to various amino acids and short peptides. Using a combination of molecular dynamics, density functional theory, and quantum transport calculations we are able to predict how the adsorption of these peptides affects the transport through the tubes.
There is significant research examining the ability of carbon nanotubes (CNT) to act as the sensing element of a biosensor. It is expected that their small size, high surface to volume ratio, and the fact that charge transport is entirely on the surface contribute to enhanced sensitivity.
This research investigates the effect of biomolecule adsorption on the electrical properties of CNTs. The effect of different factors on the sensitivity of the tube to the adsorbed molecule is being analyzed. The factors under consideration are: the tube length, the chirality, the charge and structural differences among the adsorbed species.
The research uses a combination of numerical simulation tools to analyze the biosensor. Initially, molecular dynamics simulations (MD) are used to determine the relative coordinates of the tube and biomolecule atoms after exposure to the biomolecules in water. Following this, a series of density functional theory/non-equilibrium Green's function (DFT/NEGF) simulations are used to explore the changes induced in the electrical properties of the tube upon the adsorption of the biomolecule. Our latest results show a significant modulation of the current in semi-metallic CNTs in a simple two-probe configuration upon adsorption of charged amino acids.