Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Engineering
Enhanced Fabrication Of Microdroplet Generator Nozzle Arrays: Optimizing Koh Etching For Microfluidic Applications, Hongyu Bai
McKelvey School of Engineering Theses & Dissertations
Ultrasonic microdroplet generators are useful devices with broad applications ranging from aerosolized drug delivery to three-dimensional (3D) printing-based additive manufacturing. One such technology comprises a microfabricated array of nozzles with droplet production driven by a piezoelectric transducer. The present study focuses on refining a critical fabrication step, anisotropic wet etching of pyramidal nozzles using a basic potassium hydroxide (KOH) solution. Given the integral role of nozzle geometry in device operation, high-precision techniques including Reactive Ion Etching (RIE), Deep Reactive Ion Etching (DRIE), and KOH wet etching were employed. A tapering geometry is preferred for acoustic wave focusing and efficient droplet …
Understanding The Interactions Between Acoustic Fields And Motile Microorganisms In Microfluidic Systems, Minji Kim
McKelvey School of Engineering Theses & Dissertations
Acoustofluidics utilizes ultrasonic standing waves in microscale fluidic channels to manipulate cells, microorganisms, and other objects sized from tens of nanometers to tens of microns. When exposed to an ultrasonic standing wave field, particles suspended in a fluid become confined to potential minima (nodes) of the acoustic field. I will present a number of related studies that involve the interactions between acoustic fields and motile microorganisms. First, I will show how an acoustic trap-and-release method enables rapid quantification of cell motility. As a demonstration, the newly developed motility assay is applied to discriminate swimming of wild-type and mutant Chlamydomonas reinhardtii …
Longitudinal Acoustic Traps: Design, Fabrication, And Evaluation For Biological Applications, Michael Moore Binkley
Longitudinal Acoustic Traps: Design, Fabrication, And Evaluation For Biological Applications, Michael Moore Binkley
McKelvey School of Engineering Theses & Dissertations
Acoustofluidics combine ultrasonic actuation with small-volume microfluidic channels to enable precise, contactless object manipulation for a range of applications from serial chemical processing to blood component separation and single-cell analysis. Micron- to millimeter-scale vibrational waves generate reproducible pressure fields within the microfluidic channels and chambers. By exploiting the material property mismatch between a particle (polymeric and silica beads, cells, etc.) and a suspending fluid, the acoustic radiation force is used to move particles toward regions of low (nodes) or high pressure (antinodes). An understanding of these field-particle interactions is applied to design and implement complicated channel architectures for preferential segregation …