Ph.D, Biomedical Engineering
Biomedical Engineering Department
University of California, Los Angeles
Personal Journal

Selene is a Ph.D. candidate in Biomedical Engineering. Her research interests include magnetic microactuators, hydrocephalus, and biological interface of MEMS devices. Her career interests are technology management and medical device research and development.

• Ph.D., Biomedical Engineering, University of California, Los Angeles, December 2008
  
  • A MEMS-Enabled Ventricular Catheter for Hydrocephalus
  • Ph.D. Prospectuspdf

• M.S., Biomedical Engineering, University of California, Los Angeles, December 2005
  
  • Thesis: In-Vitro Model to Assess Occlusion of Cerebrospinal-Fluid Catheters pdf
• B.S., Electrical Engineering, University of California, Los Angeles, June 2002

• A MEMS-Enabled Ventricular Catheter for Hydrocephalus (UCLA, Present)
• Circuit testing to evaluate performance of electrodes for use in retinal prosthetic implants (UCLA, 2002)
• Design and implementation of a footswitch sensor system required to record gait characteristics in spinal cord injury patients (UCLA, 2002)

• BE 180 - Systems Integration in Biology, Engineering, and Medicine I (SIBEM I) (Fall 2006)
• BE 181 - Systems Integration in Biology, Engineering, and Medicine II (SIBEM II) (Winter 2007)

• NS M202 - Cellular Neurophysiology
• NS M203A - Neuroanatomy
• NS M203B - Neural Systems
• BME M260 - NeuroEngineering
• BME CM180 - Introduction to Biomaterials
• BME 282 - Biomaterial Interfaces
• BME 298 - Tissue Engineering and Biomaterials Laboratory
• EE M150 - Introduction to MEMS
• EE M150L - Introduction to MEMS Laboratory
• EE M250A - MEMS Fabrication
• EE 250B - MEMS Physics

Hydrocephalus Shunt
(image taken from Children’s Hospital of Atlanta)

One of the most common treatments for patients with hydrocephalus is the surgical implantation of a cerebrospinal-fluid shunt. Over 25,000 shunt operations are completed each year in the U.S. alone. Patients who receive implanted shunts are dependent on the device functioning properly.

Unfortunately, this device, which is so critical to managing hydrocephalus, has a substantial failure rate. A malfunctioning (or obstructed) shunt can be a life-threatening condition. On average, 85% of people with shunts have at least two shunt-revision surgeries in their lifetime. A minority of patients are plagued with recurrent shunt obstructions and may undergo over 100 shunt revisions. Shunt-replacement surgeries can cause temporary and sometimes significant morbidity. Each successive shunt revision may cause brain injury and increases the risk of shunt infection. Not only are shunt-replacement surgeries a cause of morbidity and stress for patients and families, but they also imposed economic burdens on the patient and society.

MEMS devices integrated into ventricular catheter

For this neuroengineering project, we are focusing primarily on proximal ventricular-catheter obstruction and combating the issue of cellular accumulation. The goal of this project is to design a ventricular catheter that will resist occlusion through the use of micromachining and micro-electro-mechanical systems (MEMS) technologies. We designed, fabricated, and tested a second-generation magnetic microactuator. By integrating the microactuators into the catheters, we hope to produce an improved catheter with the ability to actively combat the health-threatening occlusion process. Our goal is to develop a shunt that resists clogging so that the time between shunt-revision surgeries can be extended significantly.

Cellular layer bridging broken after actuation

Video of MEMS magnetic actuator in a cellular environment (Please reference Lee SA, Bergsneider M, and Judy JW (2006) when using the video)

When we placed our MEMS magnetic microactuator in a fluidic environment with suspension-type monocyte cells, we observed significant fluidic movement of the cellular material. The white specks shown on the top of the device prior to actuation are the inflammatory cells. During actuation, these cells are ejected from within the pit below the device.

The preliminary results show that the fabricated microactuators can produce the forces necessary to break an adherent cellular layer grown over the microactuator surface. The photograph to the far left shows an actuator with adherent cells grown over the surface. The red outline on the top right corner of the photograph indicates the area of the actuator that has been enlarged in the two photographs in the center and to the right. The effect of actuation on a cellular layer grown over the surface of the device can be seen in the before (center) and after (right) enlarged images.

• Device Design
• Experimental Design
• Personal webpage

• Cell maintenance
• Personal webpage

• Cell maintenance
• Personal webpage

• Microactuator testing
• Personal webpage

1. US Patent Disclosure‚ Self-Clearing Catheter for Clinical Implantation, submitted August 2004.
2. S. Lee, M. Bergsneider, and J.W. Judy, “Magnetic Microactuators for MEMS-Enabled Ventricular Catheters for Hydrocephalus,” UC Systemwide Bioengineering Symposium, June 24- 26, 2006, Los Angeles, CA, USA. pdf
3. S. Lee, D. Vasquez, M. Bergsneider, and J.W. Judy, “Magnetic Microactuators for MEMS-Enabled Ventricular Catheters for Hydrocephalus,” Proceedings of the 28th Annual Conference of the IEEE Engineering in Medicine and Biology Society, August 30- September 3, 2006, New York City, NY, USA. pp. 2494-2497. pdf
4. S. Lee, J. Pinney, M. Bergsneider, and J. W. Judy, “Magnetic Microactuators for MEMS-Enabled Ventricular Catheters for Hydrocephalus”, The 3rd International IEEE-EMBS Conference on Neural Engineering, May 2-5, 2007, Kohala Coast, HI, USA. pp.65-68. pdf
5. S. Lee, J. Pinney, M. Bergsneider, and J. W. Judy, “Magnetic Microactuators for MEMS-Enabled Ventricular Catheters for Hydrocephalus,” BMES Annual Fall Meeting, September 26-29, 2007, Los Angeles, CA, USA. abstract
6. S. Lee, J. Pinney, E. Khialeeva, M. Bergsneider, and J. W. Judy, “Magnetic Microactuators for MEMS-Enabled Ventricular Catheters for Hydrocephalus,” 37th Annual Meeting of the Society for Neuroscience, November 3-7, 2007, San Diego, CA, USA.abstract