NSF-ITR Meeting 10-05

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NSF-ITR Meeting 10-05 Miniaturized
Sensors Air molecules aerosols Water mole
cules cells, viruses
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Sensor Operation Sensor Specific Initial event
Transduction to a signal Measurement of
signal Communication of result
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Initial Event Binding of analyte
Interrogation of free analyte Chemical
reaction
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Binding of Analyte Gas Chemical or physical
adsorption Metal oxides semiconductors Biolog
icals Antibodies Nucleic acids Ligands
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Interrogation of free analyte Gas Ionization Sp
ectroscopy Light, microwave, mass Water Spectro
scopy Light, microwave, mass
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Transduction to a Signal Electrical Conductance
Impedance spectroscopy voltametry Light
Microwaves Absorption Fluorescence Resonance
Oscillators Mechanical motion Surface acoustic
waves
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Gas Ionization
Modi, et al., Nature, 424, 171-174, 2003
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Gas Ionization
Modi, et al., Nature, 424, 171-174, 2003
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Complex Mixtures Difficult to distinguish
components Signal of one component can
swamp others Difficult to standardize
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A Possible Solution Fractionate the analyte
stream Differentiate molecules based on
size, shape or charge On-chip family of
membranes
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• On-chip Family of Membranes
• Controlled filtration characteristics
• ?Pattern membrane characteristics
• ?Biocompatible
• ?Use with or without electrophoresis

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Two Membrane Types Under Evaluation
?Cellulose Acetate Spin cast

• Alumina
• Nanofabricated

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Filtration Characteristics vs Preparation
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Purification DNA from Heme Membrane
electrophoresis
Mohamed, et al., Chromatography A, 2005
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Proposed Selective Gas Sensor On-chip membrane
ionization
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An Antibody Based Cell Sensor Binding agent -
immobilized antibody Electrical measurement
- impedance
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Number of captured CD4 cells vs Impedance
Mishra, et al., Biosensors Bioelcectronics,
2005.
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Amperometric biosensor using ion channel proteins
4 LAYERS 4. Protein sensing component 3.
Lipid membrane provides the proper environment
for the sensor proteins 2. Hydrogel
structural (localization and stability) 1.
Electrode Detection
I
analyte
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