Physics of Nanomechanical Sensing - bridging experiment and theory
Dr Maria Shusko
London Centre for Nanotechnology & Department of Physics and Astronomy, UCL
The development of nanotechnology poses the challenge of developing new theoretical models
applicable at the nano-scale. Miniaturisation of the existing macroscopic devices to micron sizes
often boosts their sensitivity and allows their application to detecting molecular processes.
However, the physics of operation of these devices developed for the macro-world cannot be
directly transferred to the nano-scale. We have revisited the Stoney’s formalism for cantilever
beams and extended the theory to the case of nanomechanical cantilever sensors. We propose a
quantitative model for the mechanism of signal transduction in cantilever sensors, which treats
chemical, elastic and entropic contributions to the total signal. We apply the model to study the
origin of mechanochemical response on deprotonation reactions in cantilever arrays,
functionalised with self-assembled monolayers. We show that the model gives a remarkable
quantitative agreement with experimental data, and, therefore, can be used for designing new
devices with improved sensitivity. To study more complex reactions on the cantilever sensor,
such as recognition of biomolecules, we propose a novel multiscale Meso/MM/QM modelling
technique.