Portable GMR biosensor platform with smartphone interface
Abstract/Contents
- Abstract
- Magnetic nanotechnologies have shown tremendous potential in the areas of medical imaging, therapeutics, and early diagnostics. In particular, giant magnetoresistive (GMR) spin-valve sensors, commonly used as hard disk read heads, have demonstrated significant promise as biosensors. However, access to such technologies has been limited to laboratories in developed countries. In this work, we present two custom designed portable magnetic immunoassay platforms using integrated GMR biosensors and controlled entirely via smartphone. Then, we explored if GMR sensors can detect glucose molecules. First of all we introduce Eigen Diagnosis Platform (EDP) Generation 1 (G1) that can quantitatively detect analytes of interest within 15 minutes. The platform performs biological reactions on an 8x8 array of GMR biosensors. The signals from the GMR biosensors are transferred to a smartphone connected to the platform by micro USB. A smartphone app processes the raw data and translates them into concentrations of the analytes in the sample. We have developed and implemented a unique one-step assay to complement this platform and simplify point-of-care diagnostics. As demonstrations, we detected human IgG and IgM antibodies and the hepatitis B antibody. The IgG and IgM antibodies could be detected down to 0.07 and 0.33 nanomolar (nM) concentrations, respectively, using the platform's multiplexing capability. Secondly, we further reduced the size of the station, EDP G2, to fit in half the palm of a hand, enhancing its portability. Bluetooth was added in the station to allow wireless communication between the station and a smartphone. To minimize the size and power consumption of the station, we custom designed a toroid magnetic core inductor for operating the GMR biosensors. As proof of concept, we detected THC, the principal constituent of marijuana, to enable roadside screening of impaired drivers. Because the size of THC molecule is small, a competitive assay was designed to detect THC in saliva. Using EDP G2, we quantitatively detected THC down to 15.9 nM concentrations. Thirdly, we explored if we can detect glucose using GMR biosensor. Currently, there is no antibody that can specifically bind to glucose. So, we studied transduction mechanisms for sensing glucose molecules.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2015 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Choi, Joohong |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering. |
| Primary advisor | Wang, Shan |
| Thesis advisor | Wang, Shan |
| Thesis advisor | Dutton, Robert W |
| Thesis advisor | Feldman, Brian (Brian Jay) |
| Advisor | Dutton, Robert W |
| Advisor | Feldman, Brian (Brian Jay) |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Joohong Choi. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2015. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2015 by Joohong Choi
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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