Microfluidic system has been growing rapidly and become an exciting research area, which is also referred to lab-on-a-chip science and technology, since it was introduced few decades ago. Because its unique physical characteristics, low consumption of reagents, small size that enable portability and high integration, microfluidic system has demonstrated remarkable capability to explore studies that cannot be easily performed in “macro” laboratory and shown great potential. However, challenges still exist. This thesis is focused on the challenges related to fabrication of microfluidic systems and exploration of their biological and environmental applications.

First, a protocol was developed to apply 3D printing, instead of conventional photo lithography, to produce masters for s...[ Read more ]

Microfluidic system has been growing rapidly and become an exciting research area, which is also referred to lab-on-a-chip science and technology, since it was introduced few decades ago. Because its unique physical characteristics, low consumption of reagents, small size that enable portability and high integration, microfluidic system has demonstrated remarkable capability to explore studies that cannot be easily performed in “macro” laboratory and shown great potential. However, challenges still exist. This thesis is focused on the challenges related to fabrication of microfluidic systems and exploration of their biological and environmental applications.

First, a protocol was developed to apply 3D printing, instead of conventional photo lithography, to produce masters for soft-lithographic fabrication of PDMS microfluidic systems. We characterized this method and demonstrated fabrication of several functional 3D PDMS microfluidic systems in one step. Second, a capillary-assisted on-chip pressure sensor was presented to monitor localized and dynamic pressure changing in microfluidic systems. We demonstrated fabrication and integration of this sensor as well as performed thorough characterization in five aspects. Third, a microfluidic circulatory system with a biomimetic pumping system was created to closely mimic human four-chamber heart and unidirectional systemic circulation in vitro. With capillary-assisted on-chip pressure sensor, it can generate physiological blood pressure profiles and enable cell study of response to mechanical forces. Forth, a microfluidic system with staggered herringbone mixers (SHMs) was reported to efficiently remove particulate matter (PM) in the air pollution. With microvortices generated by SHMs, it can increase collision between PM particles and channel surface and remove most of PM_2.5 with low pressure drop.