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Electrochemical Nonseparation Binding/Immunoassays Based On Solid-State Reversible Polyion Selective Sensors. Katy Fordyce Department of Chemistry Corvallis, OR 97330 Mentor: Dr. Alexey Shvarev. Electrodes (ISEs). ~ Conduct current through a cell ~ Used to detect specific species
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Electrochemical Nonseparation Binding/Immunoassays Based On Solid-State Reversible Polyion Selective Sensors Katy Fordyce Department of Chemistry Corvallis, OR 97330 Mentor: Dr. Alexey Shvarev
Electrodes (ISEs) ~ Conduct current through a cell ~ Used to detect specific species ~ Applying new method
Advantages Over Old Methods ~ Nondestructive ~ Noncontaminating ~ Short response time ~ Can be designed for selectivity ~ Unaffected by color or turbidity
Species of Interest 1. Protamine ~ Avg. charge = +20 ~ Peptide ~ Arginine Rich 2. Trypsin ~ Peptidase ~ Specific for Arginine
How Trypsin Is Used = Protamine = Other Species = Trypsin • For more information about Cystic Fibrosis, please visit www.cff.org
Basic SCE Design Cross Section View: • PVC body • Graphite core • Conducting polymer ~PEDOT • Ion selective membrane ~Hydrophobic
Membrane Composition: Important! Selectivity = Ion exchanger (DNNS+) Membrane TDDA+ H+ DNNS- Tetradodecylammonium Dinonylnaphthalenesulfonate
How Do Reversible SCE’s Work? • Constant Current SCE = Protamine ions = Na+ ions
How Do Reversible SCE’s Work? 2. Stripping Current SCE = Protamine ions = Na+ ions
Question: Can the method described earlier be used to detect the enzyme activity of trypsin? • Research Goals: • Construct electrodes which are selective for protamine • Test the electrodes in a trypsin solution to monitor enzyme activity
Data Collection Note: Both graphs share the same x-axis!
Calculating Trypsin’s Activity Step 1. Convert potential Concentration Step 2. The slope will equal the k, the reaction rate k
In Summary TDDA+ DNNS- Membrane
Acknowledgements ~ Dr. Alexey Shvarev ~ Hasini Perera ~ Dr. Kevin Ahern ~ Group 4 ~ The Howard Hughes Medical Institute