Abstract

Microfluidics, a technology of manipulating small quantities of fluids (0.1-10 µL), has drawn interest as an emerging platform for biomedical and chemical applications since its debut due to several advantages, including better precision in flow rate control, smaller required sample sizes, lower costs of analyses, and shorter turnaround times. Well-defined fluid flows are the hallmark feature of microfluidic culture systems and enable precise control over biophysical and biochemical cues at the cellular scale. One key demand for microfluidics is to control the delivered fluid flows to downstream applications. This is generally achieved via two major components – valves and pumps. Valves provide the essential flow rectifications for microfluidics, and pumps enable the necessary driving of working fluids in microfluidic systems. My dissertation introduces a passive, one-of-a-kind, in-line magnetic microvalve and a tunable, stand-alone pneumatic pump that features a 3D-printed micro-pressure regulator (µPR) to address the demand for an accessible, plug-and-play flow control platform (valving and pumping). Valves for microfluidics are typically achieved via commercial check valves, which often suffer from leakage flows when encountering low backpressure. A one-of-a-kind in-line one-way passive valve was created via a biocompatible magnetic nanocomposite microcapsule to target the low-pressure/low-flow regime. The microcapsule features a magnetic nanocomposite core with Fe3O4 nanoparticles immersed in polyethylene-glycol (PEG) encapsulated by a biocompatible parylene-C shell. Pumping fluids for microfluidics is generally achieved using displacement-based (e.g., syringe or peristaltic pumps) or pressure-controlled techniques that provide numerous perfusion options, including constant, ramped, and pulsed flows. However, it can be challenging to integrate these large form-factor devices and accompanying peripherals into incubators or other confined environments. Since microfluidic culture studies are primarily carried out under constant perfusion conditions and more complex flow capabilities are often unused, there is a need for a simplified flow control platform that provides standard perfusion capabilities and can be easily integrated into incubated environments. My dissertation introduces a tunable, 3D printed micro pressure regulator (µPR) and shows that it can provide robust flow control capabilities when combined with a high-pressured source to support microfluidic applications. This system is shown to (i) demonstrate a tunable outlet pressure range relevant for microfluidic applications (1–10 kPa), (ii) highlight dynamic control capabilities in a microfluidic network, (iii) and maintain human umbilical vein endothelial cells (HUVECs) in a multi-compartment culture device under continuous perfusion conditions

Publication Date

8-9-2024

Document Type

Dissertation

Student Type

Graduate

Degree Name

Microsystems Engineering (Ph.D.)

Department, Program, or Center

Microsystems Engineering

College

Kate Gleason College of Engineering

Advisor

Vinay Abhyankar

Advisor/Committee Member

Steven Day

Advisor/Committee Member

Robert Carter

Campus

RIT – Main Campus

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