Multiscale analysis of adsorption-induced deformation of antilever-based biosensor
Date Issued
2008
Date
2008
Author(s)
Chou, Chia-Ching
Abstract
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. The objective of this work is to develop a multi-scale theory that can analyze deformation of micro-cantilever beam subjected to bio-adsorption mechanisms calculated by ab- initio simulation and classical molecular dynamics. he multi-scale theory developed herein has successfully correlated atomistic information (the mechanism of bio-adsorption) and continuum description (bending behavior of a cantilever beam). We have studied the adsorption mechanisms of bio-molecules for SAM (self-assembly monolayer, alkanethiolic molecular for n=1~14) adsorbed on gold through ab-initio and molecular dynamics simulation. The ab-initio simulation results are in a good agreement with the literature, and the error of calculated absorption energy is less than 13％. We then extend to longer SAM simulation by molecular dynamics and the calculated absorption energy is less than 7％ when comparing with the ab-initio results.dsorption-induced stresses for different SAMs (for n=4, 6, 8, 12 and 14) are calculated by the multi-scale method. Calculated deflection based on the adsorption-induced stress agrees well with experimental measurements. Physical origin of adsorption induced deformation is revealed through the change of atomic positions and forces.
Subjects
multiscale
adsorption
biosensor
self-assembly
molecular dynamics
Type
thesis
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