Process control: electromagnetic interaction with biological media


Permanent staff: Olivier Meyer
Former collaborator:
 
Florence Ossart
Former PhD student: Cédric Gilbert

Context

This theme is to study the interactions between electromagnetic field and molecular and ionic systems. In this work we observe hydrolysis of acetylcholine kinetics in the presence of an enzyme, with a wide broadband dielectric spectroscopy (40Hz – 4GHz) with or without pulses excitations. We also follow an in vitro reaction with an electrical marker and can observe the consequences of high voltage (increasing to 1kV in around 20ns) pulses on this marker.
This study was funded by DGA “Exploratory and Innovation Research" contract, REI DGA No. 05.34.054.


Overview

The biochemical system studied is the hydrolysis of acetylcholine chloride in the presence of the enzyme acetylcholinesterase (AChE) specific to its degradation, choline chloride and acetic acid (Figure 3), in aqueous medium . The acetylcholine is the primary neurotransmitter in the human body. Roughly, the hydrolysis reaction occurs after the transmission of nervous information from one neuron to another. It allows purging the transmission channel of neurotransmitters who have accomplished their task and therefore block new entrants. The hydrolysis reaction can also re-form new radicals recovered in the synapses to synthesize new neurotransmitters. The experimental set-up is composed of 2 impedance analyzers (HP4291, HP4294) and one network analyzer (Agilent PNA-C) compatible with our coaxial discontinuity characterization cell which allows us to get analytical impedance data from 40Hz to 4GHz. Impedance data points are then analytically inverted to complex permittivity and complex conductivity. The characterization cell is a coaxial cylinder discontinuity, with gold plated and submicron polished electrodes. The experimental set-up is composed of 2 impedance analyzers (HP4291, HP4294) and one network analyzer (Agilent PNA-C) compatible with our coaxial discontinuity characterization cell which allows us to get analytical impedance data from 40Hz to 4GHz. Impedance data points are then analytically inverted to complex permittivity and complex conductivity.


Figure 1: Instrumentation for electric and dielectric broad band characterization of liquids excited by high voltage pulses

 

 
 
Figure 2: Hydrolysis of acethylcholine reaction (AchE: Acethylcholine Esterase enzyme)

 

MDMI Team collaborates on this study with ITODYS (CNRS UMR 7086 Paris 7 university), the "Laboratoire de Neurobiologie" (CNRS UMR 8544, ENS Paris), the "Laboratoire de Neurochimie", (INSERM U 495 Hôpital de la Pitié-Salpêtrière) and CEA DAM (Bruyères le Châtel).


Related publications

  1. C. Gilbert, O. Meyer, "Measuring kinetics of enzymatic hydrolysis of acetylcholine in presence of high voltage pulses by dielectric characterization", ADVANCED ELECTROMAGNETICS SYMPOSIUM, AES 2012, 16 – 19 APRIL 2012, Paris
  2. C. Gilbert, O. Meyer, "Enzymatic Acetylcholine Hydrolysis Modification by High Voltage and Fast Rise Time Pulsed EMW Using Dielectric Spectroscopy", PIERS 2011, Marrakech, 20/03/11
  3. C. Gilbert, O. Meyer, "Cast and accurate dielectric characterization technical to get various electrolytic parameters", PIERS 2011, Marrakech, 20/03/11
  4. O. Meyer, M. Delmotte, J-C. Lacroix, R. Weil, A. Loupy, F. Maurel, A. Fourrier-Lamer, “How broad band (from radio frequency to microwaves) dielectric parameters describe synthetic chemical reactions”, J. Phys. Org. Chem. 21, pp. 738-746 (2008).
  5. A. Fourrier-Lamer, M. Delmotte, A. Loupy, J.-C. Badot, R. Weil, O. Meyer, « Énergie d'activation de relaxation. Énergie d'activation de réaction chimique. Comparaison des énergies lorsque le dipôle électrique occupe le site réactionnel », Ann. Chim.-Sci. Mat. Vol 33, 4, p.271-292(2008)..
  6. S. Chevalier, O. Meyer, A. Fourrier-Lamer, A. Petit, A. Loupy, F. Maurel, "New instrumentation for the comprehension of chemical reactions under microwave and classical heating with the aid of a wide frequency band dielectric spectroscopy ", Eur.Phys. J. AP 15, p 223-229, 2001.