Biologically-inspired Microfluidic Platforms and Aptamer-based Nanobiosensors
Recent advances in micro/nano- technologies have shown high potentials in the field of quantitative biology, biomedical science, and analytical chemistry. However, micro/nano fluidics still requires multi-layered structures, complex plumbing/tubing, and external equipments for large-scale applications and nanotechnology-based sensors demand high cost. Interestingly, nature has much simpler and more effective solutions. The goal of this dissertation is to develop novel microfluidic platforms and nanobiosensors inspired by biological systems.
In this dissertation, I report the development of a biologically inspired bidirectional fluidic diode motivated by the xylem pores, which allows designing a functional large-scale microfluidic circuit and autonomous fluidic controls without any delegate efforts on fluid regulation. The biologically inspired bidirectional fluidic diode requires only a single-layered structure and a single pressure source to regulate flow in both directions through the entire platform. The operational conditions are precisely estimated based on the fully developed analytical model, which considers the hysteresis of contact angles and effects of fabrication limitations. To demonstrate its many possible applications, I show large-scale, spontaneous droplet-patterning and colonized cell-patterning programmed with the uni- and bi-directional fluidic diodes in the microfludic platform. In addition, inspired by target recognition in nature, an aptamer-based nanoplasmonic sensor, `aptasensor' is presented by detecting a coagulation protein, human α-thrombin. Also, I present an aptasensor targeting vascular endothelial growth factor-165 (VEGF165), a predominant and effective cancer biomarker for the diagnostics of various solid cancers. The integration of an aptasensor into a microfluidic platform is demonstrated by applying the VEGF165 aptasensor to detect secreted VEGF165 from breast cancer cells cultured in a microfluidic platform.
I envision that elucidation of mechanisms underlying in biological systems will inspire to create new technologies for the application to precision biology, biotechnology, and medicine. Furthermore, the developed biologically inspired engineering will provide physical insights, analytical models, and useful tools for the better understanding of biological systems.