Development of opto-electrokinetic addressing tools for assembly of biological cells and optoelectronic devices in microarrays.

摘要

Heterogeneous integration is a body of processes and methods to integrate multiple objects and functionalities on a single chip, where the main purpose is to achieve complex systems (e.g. lab-on-a-chip) through the integration of components that are individually optimized in dissimilar materials. Current technologies are limited by slow, serial, inefficient and expensive procedures. In this thesis, we present novel heterogeneous integration processes based on electric field addressing and optical addressing that utilize fluidic self-assembly, a diode-like solid-liquid interface, and electrophoretic and electroosmotic transport of charged objects on patterned electrode arrays. As compared to other techniques, our proposed platform has several distinguishing features: parallelism, speed, pattern efficiency, low power, ease of substrate design, lack of interconnection issues, nondestructive and electrically assisted fluidic self-assembly, which in turn minimizes the cost of the heterogeneous integration process.; The first technique utilizes an electrochemical system that achieves massively parallel arraying of charged objects electrophoretically and electroosmotically. The electric field distribution inside the system is modeled for two cases: inorganic devices/deionized water and cells/Krebs Ringers Buffer using conductivity and zeta potential measurements made for each constituent. Using this model, we predict the effects of object concentration, size, relative position, type of the buffer solutions and patterned electrode configuration on the electric field distribution, and thus, on the electrokinetic transport of objects. Next, the experimental system is utilized to form single or multiple object arrays both with optoelectronic devices (light emitting diodes) and mammalian cells (murine neural stem cells, murine 3T3 NIH fibroblasts, primary rat hepatocytes and a human fibrosarcoma cell line). Cells are examined morphologically under phase contrast microscopy as well as followed for mitotic capability. No gross morphologic changes or modifications in growth rate are observed during one week.; In addition to electrical addressing, we also present an optical technique for the micromanipulation of polymer spheres and live cells using multi-beam optical tweezers. Multiple objects (3) are simultaneously manipulated with Vertical Cavity Surface Emitting Lasers (VCSEL) driven optical micro beams. As in the electrical addressing system, effects of object properties and buffer composition on the trapping force are predicted and compared with experimental results. Finally, we present a model of the relevant physical phenomenon that will facilitate further development of these techniques into practical devices with potential applications in numerous heterogeneously integrated systems, both in chip-based cellular biosystems (e.g. for cell biology research, drug discovery, and tissue engineering) and in array-based optical communication systems (e.g. free-space optics, displays).