Theoretical analysis of detection sensitivity in nano-resonator-based sensors for elasticity and density measurement

Abstract

Detection sensitivity is one of the essential indices for nano-resonator-based sensing. Multiple mechanisms, such as the counteractive effects of mass and stiffness, have been revealed to contribute to the detection sensitivity, making the sensitivity analysis a complex and under-explored issue. In this study, we develop an analytical frequency model and quantitatively reveal how the detection sensitivity relies on the complex interactions between the nano-resonator-based sensor and the biochemical adsorbate for the measurement of elasticity and density. We further specify the detection limits and approaches to enhance the detection sensitivity for mechanical properties of biochemical adsorbate in nano-resonator-based label-free measurements. Results indicate that the detection sensitivity to elasticity/density could be exponentially enhanced by decreasing the elasticity/density ratio between the adsorbate and the nano-resonator until it reaches the limit. Besides, it is effective to maximize the detection sensitivity through the deposition of the biochemical adsorbate at specific regions combined with the optimization of its geometry according to the mechanical property to be measured. The maximum detection sensitivity to the elasticity relies on the distribution and geometry of the adsorbate more than that of the density. This study provides significant insights into the identification of biochemical nano-entities and helps to enhance the accuracy and capability of the nano-resonator-based sensors in mechanical measurements.