A STUDY ON THE CENTRIFUGAL FORCE-BASED FLUIDIC SYSTEM FOR BIOMEDICAL APPLICATIONS

Abstract

This dissertation focuses on the design, fabrication, evaluation, and application of a centrifugal force-based fluidic system based on macro and micro scale engineering disciplines. Unlike other fluid control forces including electrical force, compression force, magnetic force, etc., centrifugal force is capable of manipulating fluids ranging from macro- to micro-scales with high efficiencies regardless of fluid properties. Accordingly, centrifugal force has been extensively used for a great number of biomedical applications. However, the design optimization of such centrifugal force-based fluidic system for practical use is still under investigation due to the inadequate integrating technique, especially for clinical settings, and the strong dependency on geometric designs within spatially varying three different rotational forces (centrifugal, Coriolis, and Euler forces) to precisely regulate the flow of the fluid. Therefore, this dissertation aims to develop a centrifugal force-based fluidic system appropriate for either clinical or biological research environment based on thorough investigations of the fluid flow, the environments created by the rotational forces, and the geometric designs of the system at both the macro- and micro-scale. The macro-scale study involves the evaluation of design strategies for developing a smart all-in-one cardiopulmonary circulatory support device (CCSD) applicable to diverse clinical environments (emergency room (ER), intensive care unit (ICU), operation room (OR), etc.) (Chapter 2, Section 2.1), the evaluation of hemolytic characteristics of centrifugal blood pump (Chapter 2, Section 2.2), and the evaluation of drug sequestration (Chapter 2, Section 2.3) in CCSD component. Smart all-in-one CCSD equipped with a qualified low hemolytic centrifugal blood pump developed in this study resulted in low hemolysis with a free plasma hemoglobin level far less than 50 mg/dL, and an oxygenator membrane made of polyurethane fibers was turned out to be especially susceptible to the analgesic drug loss (41.8%). The micro-scale study involves the numerical evaluation of the Coriolis effects on fluid flow inside a rotating microchannel (Chapter 3, Section 3.1), the feasibility study for the development of a centrifugal microfluidic-based viscometer (Chapter 3, Section 3.2), the evaluation of hypergravity-induced spheroid formation (Chapter 3, Section 3.3), and the cellular adaptation study to hypergravity conditions using human adipose derived stem cell (hASC) and human lung fibroblast (MRC-5) (Chapter 3, 3.4). Application studies performed under fundamental understanding of the microfluidic flows in rotating platform demonstrated new potential uses for centrifugal microfluidic technologies especially for cell research, revealing that hypergravity conditions can be an important environmental cues affecting cellular interactions. Through evaluating various types of centrifugal force-based fluidic system designs for both practical applications and bench-scale experiments, considerable potential of centrifugal force-based fluidic system for introducing new paradigms in the development of medical devices and biomedical research has been demonstrated. The unprecedented integration technique to further miniaturize and improve usability of the centrifugal force-based system might facilitate product innovations, fostering its wide acceptance in the future (Chapter 4).