  We studied the dynamical response of a nanomechanical resonator to
biomolecular (e.g. DNA) adsorptions on a resonator's surface by using a
theoretical model, which considers the Hamiltonian H such that the potential
energy consists of elastic bending energy of a resonator and the potential
energy for biomolecular interactions. It was shown that the resonant frequency
shift of a resonator due to biomolecular adsorption depends on not only the
mass of adsorbed biomolecules but also the biomolecular interactions.
Specifically, for dsDNA adsorption on a resonator's surface, the resonant
frequency shift is also dependent on the ionic strength of a solvent, implying
the role of molecular interactions on the dynamic behavior of a resonator. This
indicates that nanomechanical resonators may enable one to quantify the
biomolecular mass, implying the enumeration of biomolecules, as well as gain
insight into intermolecular interactions between adsorbed biomolecules on the
surface.
