Chemical Sensing and Biological Networks

1
Chemical Sensing and Biological Networks

• Alexander Scheeline
• Department of Chemistry
• University of Illinois at Urbana-Champaign
• 600 S. Mathews Ave.
• Urbana, IL 61801
• scheelin_at_scs.uiuc.edu

Specifics of molecules dont matter L. Chua,
Physicist
Only specifics of molecules matter A.
Scheeline, Chemist
2
Measurement Issues

• Multiple species, simultaneously
• Multiple spatial scales
• Limited quantities
• Temporal variations (if in situ)
• Avoid perturbing system- complexation-
  photochemistry- metabolic shift

3
Prior Success
Peroxidase-oxidase Oscillator Horseradish
Peroxidase NADH O2 Methylene Blue (Chaos if
2,4-dichlorophenol added)
4
Next Myeloperoxidase
5
Sensor Requirements

• Absorption pathlength 1 mm
• Fluorescence feasible
• If electrochemical, lt 200 ?m support
• 5 enzyme redox states
• 3 NAD redox states
• 3 (4?) oxygen redox states
• Any other unbuffered species

6
Enzyme Handling Requirements

• No quartz or PDMS interfaces (polyfluoroethers
  newly reported)
• Facile gas exchange
• Open system
• Selective retention of large, small, both, or
  neither molecules

7
Reactor (being designed)
8
Amperometric Sensor
9
Then what?

• Electrophoretic/electroosmotic flow to
  electrospray/FT mass spectrometer
• Noise-induced Hearing Losscorrelation with
  oxidative stress
• Long-term dynamics in peroxisomes 20 enzymes,
  lipid metabolism, amine oxidation

10
Acknowledgement

• Amperometric sensor National Organization for
  Hearing Research (co-PI Jonathan Siegel,
  Northwestern Univ.)
• Levitated drops Research Corp. (starting 6/1/04)