Fabrication and Characterization of Laser-Micromachined Polypyrrole-based Artificial Muscle Actuated Catheters

Kenneth Lee

The Edward S. Rogers Sr. Department of Electrical and Computer Engineering (Photonics)

Abstract:

Polypyrrole (PPy) polymer is an artificial muscle actuator that possesses numerous characteristics attractive in guiding and improving functionality of biomedical catheters for surgical procedures. Ablative laser micromachining was investigated and characterized as means to enable precision fabrication of active catheters capable of two-dimensional positional control. A KrF excimer laser (248 nm, 15 ns) was applied to form electrically isolated channels on PPy-coated catheters such that active actuation of catheters could be demonstrated. However, one major drawback of PPy actuators is the slow speed of electrical actuation, which is proportional to the diffusion rate of ions in and out of the polymer-liquid surface under an applied electric potential. Employing a femtosecond fiber laser (1045 nm, 400 fs), surface texturing of microhole arrays has therefore been systemically applied to PPy films (thickness 20 to 40 ?m) to increase the surface porosity, and thus increase the surface area accessible for ion transfer.

Catheters were coated with PPy, electrically isolated by laser machining, and followed with digital video camera characterization of the electrically induced bending radius. Combining such catheters with optical coherence tomography, which can provide subsurface visualization of biological tissue, imaging capability using the active catheter tip is demonstrated. Such PPy actuator-enabled catheters promise new directions for biomedical imaging and diagnostics.

 

Biography:

Kenneth Lee is a PhD candidate in the Department of Electrical and Computer Engineering at the University of Toronto where he is exploring ways to enhance the performance of conducting polymer actuators. He also works as a research assistant at the Princess Margaret Hospital and the Ryerson University on optical coherence tomography (OCT) related projects. He is currently involved in the development of multichannel OCT system and digital signal processing (DSP) algorithms for real-time large data volume acquisition and parallel data processing.