Michel M. Maharbiz (Advisor)

Research Advised by Professor Michel M. Maharbiz

BPN823: Automated System for Assembling a High-Density Microwire Neural Recording Array

Travis L. Massey
2016

Assembly at the microscale involves manipulation of one or more components relative to another in order to create a microstructure or device composed of these two or more components that would be difficult or impossible to monolithically fabricate. One specific class of problems that is well suited to microassembly rather than microfabrication is the creation of very high aspect ratio out-of-plane microstructures. As size and complexity of these out-of-plane microstructures grows, it becomes compelling if not necessary to automate the device assembly. To this end, we are developing...

BPN771: Silicon Carbide ECoGs for Chronic Implants in Brain-Machine Interfaces

Camilo A. Diaz-Botia
2017

Several technologies have been developed for interfacing with the brain such as microwires, electrode arrays, and electrocorticography (ECoG) arrays. While each of them has strengths and weaknesses, they all share a common disadvantage of limited device longevity due to a variety of failure modes; these include scar tissue formation and material failure, among others. A particularly pronounced problem is the failure of the insulating material at the insulator-conductor interfaces (e.g. recording sites and insulated conducting traces). Damage to these vital interfaces compromises...

BPN854: Wearable Ultrasound System for Chronic Neural Recording

Joshua E. Kay
2017

Chronic monitoring of nerve activity with minimally invasive medical devices creates broad opportunities from therapeutic treatments to human augmentation. These closed-looped neural recording and modulation systems require small, low power wearable devices to enable freely moving subjects while still allowing real- time processing of recorded data. An ultrasonic backscatter system called Neural Dust (ND) demonstrated ultrasound's increased power efficiency over electromagnetic (EM) energy for sub-mm scale implantable devices used for wireless electrophysiological neural recording....

BPN714: Impedance Sensing Device to Monitor Pressure Ulcers

Amy Liao
Monica C. Lin
2018

Chronic cutaneous wounds affect millions of people each year and take billions of dollars to treat. Formation of pressure ulcers is considered a "never event" - an inexcusable, adverse event that occurs in a healthcare setting. Current monitoring solutions (pressure-distributing beds, repositioning patients every few hours, etc) are very expensive and labor intensive. In response to this challenge, we are developing a novel, flexible monitoring device that utilizes impedance spectroscopy to measure and characterize tissue health, thus allowing physicians to objectively monitor...

BPN838: Dosimetry Dust: An Implantable Dosimeter for Proton Beam Therapy Treatment of Ocular Melanomas

Stefanie V. Garcia
2017

Proton beam therapy is a well-established medical procedure for treating certain kinds of cancer, and is uniquely suited for treatment of head, neck, and eye tumors. In order to effectively treat a patient’s tumor, medical physicists have developed various simulations to model proton interactions with tissue and create a patient specific treatment plan that determines optimal gaze angles, the depth of penetration, and width of the spread-out-Bragg Peak necessary to encompass the target tumor. Despite the continuous improvements in medical physics treatment plan simulations, improper...

BPN765: Full-Field Strain Sensor for Hernia Mesh Repairs

Amy Liao
2017

Each year, more than 400,000 ventral hernia repairs are performed in the United States. A hernia is the protrusion of an organ through a weak spot in the surrounding muscle or connective tissue that normal contains it. Large ventral hernias (hernias that occur in the abdominal wall) are typically treated by suturing in a surgical mesh to cover and overlap the hernia defect. The surgical mesh provides additional support to the damaged tissue surrounding the hernia. However, in 25-40% of patients, the hernia repair fails, resulting in recurrence of the hernia, along with other...

BPN900: Wireless neural sensors: Robust ultrasonic backscatter communication in the brain

David K. Piech
2018

Brain-machine interfaces provide an artificial conduit to send information to and from the brain, and modulate activity in the brain. These systems have shown great promise in clinical, scientific, and human-computer interaction contexts, but the low reward/risk ratio of today’s invasive neural interfaces has limited their use to an extremely niche clinical patient population. It has been shown that ultrasonic backscatter communication can enable the sensing and stimulation of neural activity with extremely small wireless implants, which can both improve performance and reduce risk....

BPN744: Self-Destructing Silicon

Joseph Greenspun
Osama Khan
Travis Massey
Brad Wheeler
Ryan Shih
2017

Funded under the DARPA Vanishing Programmable Resources (VaPR) program, this project explores the fundamental issues associated with making wireless sensor nodes disappear after achieving an objective. The MEMS Hammer is a micromachined device capable of storing mechanical energy and delivering that energy to a target. It has been used to fracture other microfabricated structures made of silicon and silicon dioxide. The MEMS Hammer is capable of storing a wide range of energies with the upper limit exceeding 10uJ. These devices have been characterized to determine the tradeoffs among...

BPN573: Fabrication and Microassembly of a High-Density Carbon Fiber Neural Recording Array

Travis L. Massey
Jason F. Hou
2018

We present a 32-channel carbon fiber monofilament-based intracortical neural recording array fabricated through a combination of bulk silicon microfabrication processing and microassembly. This device represents the first truly two-dimensional carbon fiber neural recording array. The five-micron diameter fibers are spaced at a pitch of 38 microns, four times denser than the state of the art one-dimensional arrays. The fine diameter of the carbon fiber microwires affords both minimal cross-section and nearly three orders of magnitude greater lateral compliance than standard tungsten...

BPN780: Impedance Spectroscopy to Monitor Fracture Healing

Monica C. Lin
2018

An estimated 15 million fracture injuries occur each year in the United States. Of these, 10% of fractures result in delayed or non-union, with this number rising to 46% when they occur in conjunction with vascular injury. Current methods of monitoring include taking X-rays and making clinical observations. However, radiographic techniques lag and physician examination of injury is fraught with subjectivity. No standardized methods exist to assess the extent of healing that has taken place in a fracture, revealing the need for a diagnostic device that can reliably detect non-union in...