Piezoelectric Properties of Adsorbed DNA Films and its Influence on Detection Signals for Microbeam Biosensors

During the past decades, DNA biosensors have drawn great attention among the biodetection area. This paper is devoted to bridging the correlation between the piezoelectricity of single-stranded DNA (ssDNA) film and microbeam detection signal by formulating a multiscale model. By introducing a mesoscopic free energy of Parsegian et al., a multiscale piezoelectric constitutive equation for adsorbed DNA films is presented. Then the deflection and frequency drift of microbeam under different mechanical boundary conditions are analytically formulated. The present predictions agree with relevant experiments. Numerical results reveal that monotonic changes of elastic modulus and piezoelectric coefficient of adsorbed film is the result of microscale competition in ssDNA interchain interactions; the moment effect induced by DNA piezoelectricity works for the deflection of microbeam; the mass, axial and stiffness effects induced by DNA piezoelectricity decide the frequency drift of microbeam. These new insights not only elucidate the mechanism in complex biodetection signals but also provide an alternative concept for the realization of ultra-high sensitivity detection.