Prof. MinJun Kim
Department of Mechanical Engineering & Mechanics, School of Biomedical Engineering, Science and Health Systems, Drexel University
March 19, 2013 | 12:00 to 01:00 | 540 Cory Hall, DOP Center Conference Room
Host: Luke Lee
Bacterial chemotaxis is widely studied to understand cells’ response to a stress environment. A cell is controlled by more than 40 genes in over 14 operons that produce proteins for the structural components of the flagella, the flagellar motor, transmembrane receptors and signal transduction. The signal transduction pathway of Escherichia coli are closely related and provide a model for signal transduction in other species. Inspired by bacteria, we can develop a new class of robotics. As the field of engineered microscale robotics matures, a need for control of miniaturized systems has emerged. One approach is the utilization of live organisms as actuators. I will discuss the practical integration of bacterial flagellar motors to actuate microrobots in microfluidic environments. The ability to integrate multiple levels of functionality with a control hierarchy will be highlighted to show the realization of bacteria-powered microrobots for single-cell manipulation. I will then present bacteria-inspired robotic microswimmers with active propulsion. An external rotating magnetic field is generated by a set of electromagnetic coils in an approximate Helmoltz configuration. The magnetic field induces rotation in a flagella conjugated magnetic bead. The flagella act as both a fluidic actuator for device propulsion and as a coupler for a polystyrene bead which is used in place of a targeted localized drug delivery system, such as a drug-filled vesicle. Tetrahymena pyriformis GL (T. pyriformis) will then be introduced to show control of eukaryotes for microbiorobotics. By magnetizing ingested ferromagnetic nanoparticles (magnetite), the swimming direction of individual cells becomes controllable using external time varying magnetic fields. Since endogenous motility of a cell and the artificial magnetotaxis are combined into one system, the motion of the artificial magnetotatic T. pyriformis is able to be finely controlled. Also, “point-to-point” feedback control was performed in real time with a vision tracking system and two sets of electromagnets, showing controllability of single cells. For improved control of the position and orientation of a cell, a feasible path is planned by randomized roadmap tree (RRT) which is one of the fast path planning schemes. Combining the feedback control and the path planning scheme enables T. pyriformis to move to the target with the desired direction, which might be a basic movement for novel medical therapeutics.
www.pages.drexel.edu/~mk489/index.htm
Interested in nominating someone to speak at the BSAC Technology Seminar? We welcome you to submit a speaker nomination here