Ultrasensitive high q-factor at-cut-quartz crystal microbalance femtogram mass sensor

Abstract

A device for detecting environmental contaminants, diseases, and acute medical conditions related to heart failure identifies pathogens or troponins before infection or damage to heart muscles using an ultrasensitive high Q-factor AT-cut quartz crystal microbalance (QCM) that can measure from a single pg to a single fg. The device has a set of five disks of a QCM with a 10 mm diameter and a full coated bottom electrode, with an upper electrode with a center dot with different diameters labelled as 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm. The full coating denoting an electrically continuous thickness of at last one monolayer. Measured parameters from the five disks include Q-factors, impedance, dissipation factors (D) and frequency shift (Δf). Q-factors are used to calculate the Allman deviation σ(τ) and measured frequencies are converted to mass sensitivity using the Sauerbrey mass sensitivity coefficient (K).