Grantee Research Project Results
2004 Progress Report: The Silicon Olfactory Bulb: A Neuromorphic Approach to Molecular Sensing with Chemoreceptive Neuron MOS Transistors (CnMOS)
EPA Grant Number: R830902Title: The Silicon Olfactory Bulb: A Neuromorphic Approach to Molecular Sensing with Chemoreceptive Neuron MOS Transistors (CnMOS)
Investigators: Kan, Edwin C. , Minch, Bradley A.
Current Investigators: Kan, Edwin C.
Institution: Cornell University
EPA Project Officer: Hahn, Intaek
Project Period: May 1, 2003 through April 30, 2006
Project Period Covered by this Report: May 1, 2003 through April 30, 2004
Project Amount: $354,000
RFA: Environmental Futures Research in Nanoscale Science Engineering and Technology (2002) RFA Text | Recipients Lists
Research Category: Safer Chemicals , Nanotechnology
Objective:
The objective of this research project is to develop a silicon-based neuron MOS transistor with a novel extended floating-gate structure that permits molecular/chemical sensing. An ideal microsensor for autonomously monitoring chemical and molecular environmental hazards in both water and air should simultaneously have high sensitivity, high selectivity, large dynamic range, low manufacturing cost, simple calibration/reset protocols, long lifetime, field reconfigurability, and low power consumption. These requirements arise from considering the rapid deployment and autonomous operation of a microsensor network monitoring a large area. Our sensor, called a chemoreceptive neuron MOS (CνMOS) transistor, is expected to simultaneously meet all of these requirements and can be fabricated by minor modification or simple postprocessing of conventional CMOS integrated circuits. The modular structure and fabrication of this new device permits us to use CMOS devices optimized for high sensitivity and large dynamic range and affords us complete flexibility in the design and composition of the molecular/chemoreceptive sites.
Progress Summary:
Experimental Approach
We have established the process flow and testing setup of CνMOS sensors with nonfunctionalized molecular receptive areas for vapor and liquid sensing (e.g., water, acetone, etc.). Our measurements have validated most of our assumptions on the capability and performance of these devices. In the second year, we have fabricated prototype pixel arrays of these novel microsensors with various molecular/chemoreceptive surface coatings and characterize their selectivity, sensitivities, bandwidth and spatial resolution. Surface adsorption kinetic models are constructed to facilitate parameter extraction and fast and reliable coating selection. We will establish a example table of target agents and coatings from CνMOS readings to demonstrate selectivity. We also will develop an integrated micropower neuromorphic electronic interface for such sensor arrays whose structure and function is based on what is known about the olfactory and gustatory sensory systems of animals. This interface, called the silicon olfactory bulb, will provide a distilled set of informative features that can be used by a recognition system to perform analysis and risk assessment. During the first half of the project period, we have demonstrated integrated sensing analog circuits that are able to distinguish species and concentration without the use of the fluid potential. The required analog circuit is implemented on the same foundry chip with CνMOS.
Results
The performance of our new sensor has proved to be vastly superior to that of existing chemical microsensors, such as the ion-sensitive field-effect transistor (FET) and the chemically modified FET, in nearly every important respect resulting from the internal transistor gain, reduction of the constraint on a liquid reference potential, and much better isolation between the electronics and microfluidics. We have demonstrated selectivity between species such as Na+ and K+ with various nonfunctionalized polymer coatings and molecular sensing of bovine serum albumin (BSA) and sodium dodecyl sulfate(SDS) in saline solutions and CO2 in air. We have further demonstrated modification of contact angles in the microfluidic channel interface, which is sensitive to the ionic strength and species. For the second year, analytical models for AC impedance and transition responses have been established, which significantly enhance the applicability and design considerations of the DC model based on the Helmholtz potentials and diffusive layers. We will perform more verification and benchmarks with integrated sensing circuits for model corroboration in realistic operational conditions.
We expect to be able to develop a complete system, including both a sensor array and the silicon olfactory bulb, that can be fully integrated, perhaps on a single chip, and will dissipate only a few hundred microwatts of power in total. Such devices could be manufactured in large numbers very inexpensively and deployed rapidly as environmental sensors, running autonomously for long periods of time on either solar power or miniature chemical batteries. During the first half of the project period, we have demonstrated the characteristics of C nMOS in the proof-of-concept manner for sensitivity, selectivity, power consumption, and system integrability with CMOS technology and circuits.
Environmental Benefit/Relevance
The developed CνMOS sensor with its all-around sensor specification for an autonomous microsystem deployment can bring great benefit to environmental sensing in a wide deployment mode. The new sensor is inexpensive to integrate with other necessary electronics for data processing and communication (on the same chip) and can achieve a wide range of selectivity and sensitivity. It is ready for product development to target specific chemicals and molecules in aqueous or air environments.
Future Activities:
In Year 3 of the project, we plan to establish:
- the universal sensors for chemicals, molecules, pressure and light with only post-processing steps on standard CMOS chips,
- continuation of developing the electrowetting on dielectric (EWOD) model and associated experimental characterization,
- better microfluidic integration,
- and time resolution for molecular movement detection.
Journal Articles on this Report : 4 Displayed | Download in RIS Format
Other project views: | All 23 publications | 6 publications in selected types | All 6 journal articles |
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Kim M, Shen NYM, Lee C, Kan EC. Fast and sensitive electret polymer characterization by extended floating gate MOSFET. IEEE Transactions on Dielectrics and Electrical Insulation 2005;12(5):1082-1087. |
R830902 (2004) R830902 (Final) |
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Shen NYM, Liu Z, Lee C, Minch BA, Kan ECC. Charge-based chemical sensors: a neuromorphic approach with chemoreceptive neuron MOS (C/spl nu/MOS) transistors. IEEE Transactions on Electron Devices 2003;50(10):2171-2178 |
R830902 (2004) R830902 (Final) |
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Shen NY, Liu Z, Jacquot BC, Minch BA, Kan EC. Integration of chemical sensing and electrowetting actuation on chemoreceptive neuron MOS (C vMOS) transistors. Sensors and Actuators B: Chemical 2004;102(1):35-43. |
R830902 (2004) R830902 (Final) |
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Shen YN, Liu Z , Peng S-Y, Jacquot BC, Minch BA, Kan EC. Response analyses on polymeric surface coatings for charge-based sensing in chemoreceptive neuron MOS (CνMOS) transistors. IEEE Sensors Journal (accepted, 2005). |
R830902 (2004) |
not available |
Supplemental Keywords:
nanotechnology, neuron MOSFET, molecular and chemical sensors, electrochemistry, physics, engineering, water, air monitoring and measurement methods, sustainable industry/business, analytical chemistry, chemistry and materials science, environmental chemistry, environmental engineering, aerosol analyzers, chemoreceptive neuron transmitters, microsensors,, RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, Sustainable Industry/Business, Chemical Engineering, Environmental Chemistry, Monitoring/Modeling, Analytical Chemistry, Environmental Monitoring, New/Innovative technologies, Chemistry and Materials Science, Engineering, Chemistry, & Physics, Environmental Engineering, environmental measurement, microsensors, air pollution control, nanotechnology, chemoreceptive neuron transistors, air pollution, environmental contaminants, chemoreceptive neuron transitors, aerosol analyzers, silicon olfactory bulbProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.