Microdevices for Implantation and Neuroscience
Open Access
- Author:
- Zhou, Mingda
- Graduate Program:
- Bioengineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- October 14, 2015
- Committee Members:
- Siyang Zheng, Dissertation Advisor/Co-Advisor
Siyang Zheng, Committee Chair/Co-Chair
William O Hancock, Committee Member
Yingwei Mao, Committee Member
Nanyin Zhang, Committee Member - Keywords:
- MEMS
Implantation
gas chromatography electroantennography
Electroporation - Abstract:
- Micro-electro-mechanical system (MEMS) and the microfabrication techniques, whose feature size covers a range of several microns to hundreds of microns, provides us the potential to develop miniaturized sensor and actuator for implantation applications and an unique way to address the biological and biomedical issues in microscopic and mesoscopic level. Three different devices were developed with MEMS techniques. One device is an implantable MEMS pressure sensor prototype that can be seamlessly integrated with continuous flow left ventricular assist device (LVAD) to enable real-time control, optimize its performance and reduce its risks. The pressure sensing mechanism is based on Fabry-Pérot interferometer principle. The sensitivity, range and response time of the pressure sensor are measured and validated to meet the requirements of LVAD pressure sensing. A second device is a novel MEMS chopper modulator (MCM) that enables the chopper modulation in gas chromatography electroantennography (GC-EAG) by modulating the effluent from the GC separation column before it reaches the insect antenna. The key component of MCM is a MEMS flow control chip, fabricated with fully GC compatible materials using microfabrication techniques. It can reside inside the conventional GC oven, switch GC flow with on/off ratio as high as 1000:1, and operate reliably for more than 1 million switching cycles at working temperature of 300 °C. Using the new MEMS chopper modulated GC-EAG (MCM-GC-EAG), we demonstrated as little as 1 pg pheromone cis-11-hexadecenal could be successfully detected using the antenna harvested from male moth Helicoverpa Virescens. A third device is a needle electroporator, which is an integrated microdevice that can perform high spatial resolution electroporation, targeting several neurons to tens of neurons, in deep brain. In vitro electroporation on MDA-MB-231 cells was performed with the device and cell membrane non-permeable dyes to investigate the effect of electric impulse (pulse amplitude, pulse duration, pulse interval and the number of pulses) on the success of electroporation and the viability of cells, and to determine the optimal condition. In vitro electroporation with was performed on HEK-293T cells using the device and plasmid that encodes green fluorescent protein (GFP) gene to confirm that the optimal condition determined with fluorescent dyes also works for plasmid. In vivo electroporation with a plasmid that encodes GFP as a reporter gene was successfully demonstrated at hippocampus of mouse brain.