The next trend in micro and nano technology is in the direction of integrating micro and nano systems with active bio-elements and means of information transduction. Along this line, the PI's propose to design, fabricate, and test a novel electrical microfluidics pump actuated by biological cell motors. The proposed micro pump will be realized through the integration of a harmless strain of E. coli cells with a MEMS-based microfluidics channel. Each E. coli cell consists of several flagella driven at the base by a rotary motor. If the cell is attached to a surface by a single flagellar filament, the motor turns the whole cell body at a high rotational speed. The proposed design utilizes this mechanism to transport liquid in a microfluidics channel through viscous pumping. According to a preliminary fluid mechanics simulation, the proposed cell motor pump can deliver a flow rate of almost 0.25 nanoliter per minute. Electro-rotation will be used to electrically control the cell rotational speed and thus the flow rate. With this novel control scheme, it is envisioned that the proposed integration of cell actuation biology and MEMS will result in an intelligent microfluidics system for next generation applications.
The following objectives have been established for the proposed project.
Design and fabricate MEMS microfluidics channel: A series of fluid dynamics simulations will be conducted to investigate the dependence of the volumetric flow rate in a microfluidics channel on the distribution and rotational speed of cell motors. Based on the results, a microfluidics channel system will be fabricated using MEMS processing techniques on a silicon substrate. The sidewall of the channel will consist of gold pads for cell attachment and metal electrode for controlling cell rotation through electro-rotation.
Integrate cells with microfluidics channel: Gold will be used as the interface material between the cells and the microfluidics channel. Two mature technologies will be adapted to attach the cells to a gold patterned substrate. One involves generation of a suitable substrate for attachment of the flagellar filaments. The second concentrates on engineering flagellar filaments that will provide good ligands for attachment.
