Re: Pulsed electrical fields anti-microbial actions

Here's one thats not about electro-med, but rather about food treatment, but still gives us more proven specifics about possible extrapolated protocols for electro-med. (While high voltages are used(KV) I assume since no ionisation occurs this is still interesting data for the approach to electrocuting organisms "in vivo"  vs culture dishes.

"Electric field intensity is one of the main factors that influences microbial inactivation (Hüshelguer and Niemann 1980; Dunne and others 1996). The microbial inactivation increases with an increase in the electric field intensity, above the critical transmembrane potential (Qin and others 1998). This is consistent with the electroporation theory, in which the induced potential difference across the cell membrane is proportional to the applied electric field. The critical electric field E_c (electric field intensity below which inactivation does not occur) increases with the transmembrane potential of the cell. Transmembrane potentials, and consequently E_c, are larger for larger cells (Jeyamkondan and others 1999). "

"(the Voltage needed for)-- gram-negative bacteria is lower than that for gram-positive, in accordance with the smaller PEF resistance of the former. The kinetic constant for the yeast C. albicans is smaller than for gram-negative and gram-positive bacteria, implying that yeast are more resistant to inactivation with PEF than bacteria--"

"Mathematically, about 90% inactivation is achieved within the critical electric field plus 3 times the kinetic constant. In this generalized model, E_d(n) and K(n) are algebraic functions that not only depend on the electric field but also on the number of pulses or treatment time. "

"Membrane disruption occurs when the induced membrane potential exceeds a critical value of 1 V in many cellular systems, which, for example, corresponds to an external electric field of about 10 kV/cm for E. coli (Castro and others 1993)."

"The model can be simplified by not considering the relationship between the electric field and the number of pulses:

A small value for the kinetic constant [K (n) or K] indicates a wide span in the inactivation rate curve and lower sensitivity to PEF, whereas a large value implies a steep decline or higher susceptibility to PEF. Lower E_d values would indicate less resistance to the PEF treatment."

" ----- the higher the number of pulses, the lower the E_d and kinetic constant K. The high regression coefficients for all the studies show the model has potential use to predict microbial inactivation."

They list Staph A. in their chart as needing the highest V to kill it, ( no surprize there for John or PZ ). The success and ease of use with CSilver on MSRA makes it an unavoidable part of the topic, the problem in interfacing the CS with the bacteria is problematic since the Staph.A. can hide in dental tubules which are too small for most of our body fluids to enter (w the exception of dental serum) and bone stucture which has no fluid system. And makes the PEF therapy(seemingly, w only a couple of caveats. V required for one)  a good choice for dental area staph infections.  

http://www.fda.gov/Food/FoodScienceResearch/SafePracticesforFoodProcesses/ucm...