MICRO-SCALE HYBRID BIOLOGICAL-ENGINEERED DEVICES POWERED BY BIOMOLECULAR MOTORS
Open Access
- Author:
- Huang, Ying-Ming
- Graduate Program:
- Electrical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- January 29, 2008
- Committee Members:
- Thomas Nelson Jackson, Committee Chair/Co-Chair
William O Hancock, Committee Member
Jerzy Ruzyllo, Committee Member - Keywords:
- Microtubule
Molecular motors
Microfabrication
Deep glass wet etching
Microfluidics
Protein patterning - Abstract:
- The topic of this thesis is the development of state-of-the-art hybrid biological-engineered devices powered by kinesin biomolecular motors and microtubules. In order to achieve kinesin-driven microtubule transport in enclosed channels while allowing for observation with a standard fluorescent microscope, channels were fabricated in a transparent and motor compatible material with an architecture that enabled sample introduction and visualization. Channels were designed to redirect microtubules without clogging or running out of the ATP fuel that powers these motors. Developing these devices involved several areas of microelectronics and MEMS technologies, including optimizing a reliable deep glass wet etching strategy and the development of a novel adhesive bonding process. Microtubules were manipulated using AC electric fields generated by patterned electrodes and kinesin motors were micropatterned by DUV irradiation. In this work we constructed a three-tier hierarchical system of microfluidic channels that links microscale bio-motor transport channels to macroscopic fluid connections. We demonstrated that a 60 £gm diameter circular ring functionalized with motors can concentrate and align bundles of thousands of uniformly oriented microtubules which continue to move for more than 90 minutes. This confinement is the first demonstration of channel confinement of moving microtubules for times needed for realistic biomotor applications. Furthermore, the AC electric field generated by microelectrodes in low ionic strength buffers was able to collect and align bundles of microtubules for sorting and in vitro assembly of mitotic-spindle-like structures. We found that AC fields result in electroosmotic flow, electrothermal flow, and dielectrophoresis of microtubules, which can be controlled by varying the solution conductivity, AC frequency, and electrode geometry and we were able to model key aspects of the field-drive movements. A novel approach was also developed for directly patterning neutravidin protein by exposure to DUV irradiation. Neutravidin is physically absorbed onto a glass or quartz substrate, dehydrated in acetone and air-dried. Dry neutravidin-coated samples can be patterned either by top-side or back-side exposure, and the exposure time and UV wavelength were optimized to maximize pattern contrast and resolution. Biomotor-based transport alleviates the need for bulk fluid flow, which enables device miniaturization and the development of cheap and even disposable bioanalytical systems. These demonstrations provided essential building blocks for biological-engineered devices and will impact bionanotechnolgy broadly by pioneering the incorporation of protein machines into engineered devices.