Alkanethiol Self-Assembled Monolayers on Microcantilever Biosensor

Microcantilever-based biosensors are rapidly becoming an enabling sensing technology for a variety of label-free biological applications due to their wide applicability, versatility and low cost. It is thus imperative for us to reveal the physical origin of adsorption-induced deformation, and to further analyze its implication of microscopic mechanisms on macroscopic deformation. In the paper, we study adsorption-induced surface stresses and microcantilever motion in alkanethiolate SAMs on Au surface. We develop a multiscale method that can analyze deformation of micro-cantilever beam subjected to bio-adsorption mechanisms calculated by ab-initio simulation and classical molecular dynamics. The adsorption mechanisms of different SAMs adsorbed on Au(111) surface, in the dry and liquid phase, are studied by ab-initio simulation and the adsorption-induced stresses are calculated through the multiscale method. The results give insight into the atomic forces and positions that play a key role in producing adsorption-induced surface stresses and resultant mechanical bending of microcantilevers.