Adjustable frequency shift of laminated DNA microbeam under complex detection conditions by different packaging patterns

Abstract

Packaging patterns have close correlation with thermoelastic properties of sensitive layer and relevant biodetection signals of laminated microbeam. In this paper, we present a cross-scale mechanical model to explore the possibility of adjusting thermoelastic properties of DNA adsorption film and the relevant signals of microbeam under complex detection conditions by different packaging patterns. First, considering microscale interactions in DNA solutions, a unified mesoscopic free energy is developed based on the previous formulations of Parsegian et al.; then, the thought experiment method for DNA film and the force balance method for nonlinear elastic network of DNA cylinders are combined to characterize elastic properties of adsorption film; finally, an effective macroscopic model for DNA microbeam is used to predict resonance frequency shift caused by DNA adsorption and temperature fluctuation in high-valent salt solutions. Results show that, compared with the properties of classical convex-packaged film, the thermal expansion coefficient of concave-packaged DNA film in high-valent salt solutions is smaller, and its elastic modulus and prestress have larger fluctuation ranges to environmental conditions, which provide a chance to improve detection sensitivity based on frequency shift. These results are expected to provide an option for design of DNA composite materials and microbeam sensors.