Microfluidic microcantilever as a sensitive platform to measure evaporation rate of picoliters of ethanol

Abstract

Resonating microfluidic cantilevers are used for a broad range of biochemical sensing applications where a shift in the resonance frequency is used to detect minute changes in the cantilever mass. These multifunctional microfluidic microcantilevers open up opportunities for new ultrasensitive biochemical sensors wherein the target species in a carrier fluid bind to the inner functionalized walls of microfluidic channel, thereby changing the mass and hence the resonance frequency of the system for detection. In this paper, we develop computational models that predict the change in the resonance frequency as a function of change in mass for this hollow microcantilever system. We present computational models to simulate this process and validate the models using experimental data based on the evaporation of ethenol, a commonly available volatile compound. Specifically, a computational approach is presented in two variants; a one-dimensional structural beam element model, and a three-dimensional finite element model. The numerically predicted increase in the resonance frequencies due to a decrease in ethanol mass correlates well with experimental data. The models enable the determination of proof-of-concept and the rational design of novel resonant-based microfluidic microcantilever systems.