Nanoscopic modeling of a carbon nanotube force-measuring biosensor

Abstract

In this paper we perform a theoretical study of a potential design of a carbon nanotube device able to transduce forces developed at the scale of basic cellular processes into electric current variations. The first part of this study consists of an assessment of the sensitivity of the device with forces in the tens of pico Newtons (pN), developed typically at the cellular scale. In the second stage, we focus on the transduction of the deflection of a cantilever into an electrical signal, employing methods borrowed from non-equilibrium Green's functions. Several issues related to the importance of thermal effects in the proper operation of the sensor are then discussed. Following a simple method we include non-zero temperature through molecular dynamics in quantum conductance calculations that results in the displacement-current characteristic found at the end of this paper.

Keywords:

• Carbon nanotubes
• Nano-mechanical cantilever
• Biosensors
• Molecular modeling
• Multi-terminal conductance

Acknowledgements

The authors would like to thank Dr Stephan Roche for his help in elucidating the various aspects involved in modeling the quantum electronic transport. C. Roman would also like to acknowledge and thank Prof. Barbu Constantinescu for his useful comments and encouragements.