Continuous Glucose Monitoring(CGM) Biosensor
Rana Muhammad Umer
ECE 6200
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OUTLINE
• Introduction• Motivation• Principle & Design• Fabrication Steps• Conclusion
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Introduction
• Fully Implantable Device• Capacitive based sensor• Monitors Glucose level in Blood• Real-time Monitoring• No Moving Part• Dielectric Affinity Detection
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Introduction
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Motivation
• A Fully Implantable Device
• Monitors Glucose Level in Real Time
• No Mechanically Moving Parts
• No Intricate Actuator Design
• Less susceptible human and environmental disturbances
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Principle & Design
• Detects glucose-induced permittivity changes of solution of glucose sensitive polymer.
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Principle & Design
• Two Electrodes: Upper Perforated Electrode & Lower Electrode on Substrate
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Principle & Design
• Diaphragm is supported by anti-stiction posts to avoid collapsing and providing mechanical stability.
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Principle & Design
• Semi-permeable membrane to restrict polymer in u-chamber and allow only glucose to transverse.
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Principle & Design
• The solution between two electrodes acts as the dielectric material for capacitive detection.
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Fabrication Steps
1- Deposition of Gold on Si substrate for bottom electrode.
2- Deposition of Parylene passivation layer through chemical vapor deposition(CVD).
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Fabrication Steps
3- Deposition of thick sacrificial photoresist layer.
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Fabrication Steps
4- Deposition of second Parylene layer.
5- Gold layer deposited and patterned to form perforated upper electrode.
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Fabrication Steps
6- Deposition of another Parylene passivation layer on top of upper electrode.
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Fabrication Steps
7- Patterning of SU-8 reinforcement layer to form nine anti-stiction posts.
8- SU-8 spin coated to form micro-chamber.
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Fabrication Steps
9- Using SU-8 as mask Parylene layers are patterned and sacrificial layer is etched using Reactive Ion Etching.
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Fabrication Steps
10- Cellulose semi-permeable membrane is glued in the last on the top of micro-chambers using epoxy.
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Conclusion CGM biosensor uses real-time monitoring dielectric detection to monitor
the level of glucose in blood.
Affinity binding between glucose and polymer( PAA-ran-PAAPBA) results in a decrease in permittivity of solution.
Decrease in permittivity is detected by two electrodes.
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References
[1] Xian Huang, Siqi Li, Erin Davis, Dachao Li, Qian Wang, Qiao Lin; ‘A MEMS Dielectric Affinity Glucose Biosensor”; Journal of Microelectromechanical Systems, February 2014.
[2] A. Heller, “Implanted electrochemical glucose sensors for the managementof diabetes,” Annu. Rev. Biomed. Eng
[3] Y. Zhao, S. Li, A. Davidson, B. Yang, Q. Wang, and Q. Lin, “A MEMS viscometric sensor for continuous glucose monitoring,” J. Micromech. Microeng
[4] X. Huang, S. Li, J. S. Schultz, Q. Wang, and Q. Lin, “A dielectric affinity microbiosensor,” Appl. Phys. Lett.
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THANK YOU
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