Publications by authors named "Zou-Qing Tan"

An energy-based model is presented to establish the bending deformation of microcantilever beams induced by single-stranded DNA (ssDNA) adsorption. The total free energy of the DNA-microcantilever sensor was obtained by considering the excluded-volume energy and the polymer stretching energy of DNA chains from mean-field theory, and the mechanical energy of three non-biological layers. The radius of curvature and deflection of the cantilever were determined through the minimum principle of energy.

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The surface charge state at a liquid-solid interface is important to the variations in the physical/chemical properties of adsorbate film such as surface stress and the ensuing tip deflection of the microcantilever. The well-known Stoney's equation, derived more than 100 years ago, conceals the film electrical properties with the replacement of substrate deformation induced by adsorptions of particles. This implicit expression provides a shortcut to circumvent the difficulty in identifying some film properties, however, it limits the capacity to ascertain the relation between surface stress variation and the surface charge state.

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In nanoscale diagnostic systems, inhomogeneity in near-surface systems and flexibility in biostructures greatly influence the mechanical/electrical/thermal properties of biosensors and resultant detection signals. This study focuses on inhomogeneity and flexibility of DNA biofilm and characterizes its local interactions and mechanical properties. First, a flexible cylinder model of DNA chain is employed to capture the local geometric deformation characteristics of DNA molecules on microcantilever.

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Biomolecule adsorption is a fundamental process in the design of biosensors. Mechanical/electrical/thermal properties of biofilms have great influences on biodetection signals. The double-stranded DNA (dsDNA) biofilm adhered on microcantilever is treated as a bending beam with a macroscopic elastic modulus in the viewpoint of continuum mechanics.

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