Patrick Ellis: System Identification - Modeling the Nanopore

Patrick is a junior Electrical Engineering major at Bradley University who performed a System Identification on an alpha-hemolysin Nanopore System, under the guidance of Professor Bill Dunbar. The alpha-hemolysin Nanopore is an exciting new opportunity to sequence DNA faster and cheaper than any other contemporary alternative. Its ability to manipulate strands of DNA rests upon minute and extremely sensitive manipulations of input voltage.

Obtaining a System Identification is essentially receiving a validation on portions of the Nanopore System that must be estimated or assumed because of the difficulty of obtaining small measurements on the biological nano scale. The alpha-hemolysin Nanopore forms a natural biological circuit, carrying certain values that cannot be accurately measured. Patrick performed a System Identification that revealed many of the previous estimations of these unknown parameters to be highly accurate. This was completed by obtaining transfer functions for the separate parts of the system, converting these transfer functions into a single state space representation with stipulated parameters, and entering it into the Matlab System Identification Toolbox where it was then optimized and validated. This work will serve as the basis for many future manipulations and options with the alpha-hemolysin Nanopore, including implementing a Feed Forward and Capacitive Feedback. It was also found that further modeling, once a value is found for one of the capacitances in a manner other than System Identification, System Identification could be used to acquire a more detailed portrayal of the system.