AVS 66th International Symposium & Exhibition
    Biomaterial Interfaces Division Monday Sessions
       Session BI+AS+NS-MoM

Paper BI+AS+NS-MoM6
Breaking the Mass Resolution Limit of Shear Wave Resonators in Liquid through Integrated Microfluidic Channels

Monday, October 21, 2019, 10:00 am, Room A120-121

Session: Biofabrication, Bioanalytics, Biosensors, Diagnostics, Biolubrication and Wear
Presenter: Stefan Zauscher, Duke University
Authors: Z. Parlak, Duke University
S. Zhao, Duke University
D.L. French, Duke University
S. Zauscher, Duke University
Correspondent: Click to Email
Acoustic shear wave resonator sensors (SWRS), e.g., quartz crystal microbalance, are widely used in applications (e.g., thin film deposition) where their high quality factor in air or vacuum provides exquisite mass resolution. SWRS are also used as biosensors in liquid environments; however, they have not yet found widespread use outside the research environment despite their simple and robust detection modality. This is because current SWRS suffer from viscous contributions to shifts in resonance frequency, which inherently leads to low mass resolution. Furthermore, current SWRS require accurate temperature control and use large liquid volumes (~ml). Together these limitations prohibit accurate and economic measurement of surface bound mass, e.g., in protein binding assays. We show through experiments and simulations that by confining fluid into small, rigid channels oriented perpendicularly to the shear direction of the SWRS, we can manipulate liquid to behave as a lossless layer and thus perform precise mass measurements of the confined liquid. Canceling viscous effects in µ-fluidic SWRS not only enhances their mass resolution in liquid to levels observed in air/vacuum, but also enables efficient device miniaturization. Combined with the extremely small volume requirements for sensing (~nL), we show that µ-fluidic SWRS can overcome current barriers for their widespread use in diagnostic sensing and point of care applications.