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Author Topic: Killing bacteria with low voltage science fair project  (Read 17988 times)

Offline Zapper Dave

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High energy Pulsed Electric Fields ( PEF ) have been used for several years in the purification of processed fruit juices, milk, water, and other liquids. These processes use high voltages and short duration pulses because the liquids are flowing at a high velocity, due to the large volumes being processed. Current literature on the subject explains that lower voltages can be used if the number of pulses is increased and the volume is lowered. Some current applications of this are the control of microbial growth in cooling towers and backyard ponds.

The use of electricity  for killing microbes such as bacteria, protozoa, and fungi has been around since the 1750's but has not been widely recognized. The relatively few studies that have been undertaken have had difficulty getting published and few of them have had significant publicity. For this reason, a science fair project that provides good quality observations and results might open a lot of doors for the person who achieves these results.

The lowest effective voltages for killing microbes was published by Dr. Robert O. Becker, M.D. in his book "Body Electric" at about 1.0 volt and a current of only 100-200 nano-amperes.

[link removed (unsupported claims, etc)]
Some previous studies and a prior science fair project are posted below.

newbielink:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC529182/ [nonactive]
newbielink:http://www.usc.edu/CSSF/Current/Projects/J1609.pdf [nonactive]
newbielink:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC154785/ [nonactive]
newbielink:http://www.aanos.org/documents/Eff%20of%20Elect%20Stim%20on%20Bact%20Grwth.pdf [nonactive]
newbielink:http://www.rehab.research.va.gov/jour/04/41/2/merriman.html [nonactive]
newbielink:http://pacificjunction.com/wp/wp-content/uploads/2013/08/Inactivation-of-Bacteria-in-Seawater-by-Low-Amperage-Electric-Current-Appl.-Environ.-Microbiol.-2003-Park-2405-8.pdf [nonactive]
newbielink:http://www.ncbi.nlm.nih.gov/pubmed/9222036 [nonactive]


With the positive results seen in the studies above and the possible positive effects on fighting illness, why has there not been more follow-up studies. Is there just a lack of interest or could it be possible that certain other interests are suppressing additional studies? If certain voltages, currents, or frequencies we shown to effectively stop bacterial infections in the human body, this might just have a very negative effect on the sales of antibiotics or other medications but at the same time provide new improved life-saving techniques.

For additional reading consider "Body Electric" by Dr. Robert. O. Becker, M.D.

« Last Edit: 04/11/2013 09:35:59 by peppercorn »


 

Offline RD

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Re: Killing bacteria with low voltage science fair project
« Reply #1 on: 04/11/2013 07:56:32 »
High energy Pulsed Electric Fields ( PEF ) have been used for several years in the purification of processed fruit juices, milk, water, and other liquids ...  If certain voltages, currents, or frequencies we shown to effectively stop bacterial infections in the human body ...

The voltages used in High energy Pulsed Electric Fields ( PEF ) used to sterilize liquid foodstufs would be more than sufficient to rupture blood cells ...

Quote from: ieee.org
Studies on Pulsed Electric Field applications for food sterilization
 It is suggested that repetitive pulse application of the order of about 25-kV/cm electric field intensity be employed for the purpose.
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=4579228

Quote
Cells: Advances in Research and Application: 2011 Edition (Google eBook)

http://books.google.co.uk/books?id=2REmsEmWq20C&pg=PA57

i.e. If you diverted human bloodflow through the PEF device used to sterilize liquid food it would lyse the red and white blood cells, not a good idea.  [xx(]


... could it be possible that certain other interests are suppressing additional studies?

For those who think Dave is suggesting there is some sort of conspiracy to suppress his Zapper technology see point #4
« Last Edit: 04/11/2013 10:53:05 by RD »
 

Offline Zapper Dave

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Re: Killing bacteria with low voltage science fair project
« Reply #2 on: 04/11/2013 18:20:31 »
Your claim: The voltages used in High energy Pulsed Electric Fields ( PEF ) used to sterilize liquid foodstufs would be more than sufficient to rupture blood cells

Is unfounded in relationship to this post. The quoted studies are mostly low voltage, low current and do not damage the cells of higher organisms.

visually illustrates that low voltage ( less than 10 volts ), low current ( less than 10.0 ma ) can very effectively kill many microbes when applied over a reasonable time ( 1 hour ).  Even pure DC directly applied from a 9 volt battery kills some microbes. The the pulses were applied for 1 hour and then repeated again 24 hours later, when sampled 24 hours later, No visible microbial activity could be identified under the microscope at 40 time, 100 times, 400 times, or 600 times magnification, using either darkfield or brightfield illumination. A total of 8 different slides were thoroughly scanned.

The point of this posting is not to do with a specific product but to open the doors to those who are unaware or are poorly informed. There are many variables here for a student to explore in a science fair project.

Also, you posted "i.e. If you diverted human bloodflow through the PEF device used to sterilize liquid food it would lyse the red and white blood cells, not a good idea. "

Again, this is false because you are limiting the term PEF to HVHC PEF ( high voltage high current pulsed electric field ): A patent has been awarded for more than one such LVLC PEF device.

Blood electrification. Patent 5139684, granted Aug 18 1992 (filed Nov 16 1990)

Electrically conductive method and systems for treatment of blood and other body fluids and/or synthetic fluids with electric forces

Inventors: Dr. Steven Kaali and Peter Schwolsky

Abstract: A new process and system for treatment of blood and/or other body fluids and/or synthetic fluids from a donor to a recipient or storage receptacle or in a recycling system using novel electrically conductive treatment vessels for treating blood and/or other body fluids and/or synthetic fluids with electric field forces of appropriate electric field strength to provide electric current flow through the blood or other body fluids at a magnitude that is biologically compatible but is sufficient to render the bacteria, virus, and/or fungus ineffective to infect normally healthy cells while maintaining the biological usefulness of the blood or other fluids. For this purpose the low voltage electric potentials applied to the treatment vessel should be of the order of from about 0.2 to 12 volts and should produce current flow densities in the blood or other fluids of from one microampere per square millimeter of electrode area exposed to the fluid being treated to about two milliamperes per square millimeter. Treatment time within this range of parameters may range for a period of time from about one minute to about 12 minutes.

It is unfair to delete the links of someone because of claims that they might have unfounded information and then refute with unfounded claims.

« Last Edit: 04/11/2013 18:43:43 by Zapper Dave »
 

Offline RD

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Re: Killing bacteria with low voltage science fair project
« Reply #3 on: 04/11/2013 19:13:06 »
Your claim: The voltages used in High energy Pulsed Electric Fields ( PEF ) used to sterilize liquid foodstufs would be more than sufficient to rupture blood cells

Is unfounded in relationship to this post. The quoted studies are mostly low voltage, low current and do not damage the cells of higher organisms.

 I didnít introduce "High energy Pulsed Electric Fields" to this thread : you mention "High energy Pulsed Electric Fields" in the opening line of your first post.



visually illustrates that low voltage ( less than 10 volts ), low current ( less than 10.0 ma ) can very effectively kill many microbes when applied over a reasonable time ( 1 hour ) ...

Assuming your experiment is as you describe, a possible alternative explanation is that passing 10 Volts at 10mA across the (copper?) electrodes dunked into the jar has changed the chemistry of the water which has made it toxic for the things which were previously living there , i.e. electrolysis. If the life in the jar is extinguished if you put the electrodes against the outside of the jar then that would support your claim that the applied electric field is directly killing the occupants.


It is unfair to delete the links of someone because of claims that they might have unfounded information and then refute with unfounded claims.

The link deleted was to your own commercial site where you sell products , so effectively an advertisement , plugging your own products via such links is not permitted in this forum ...

Quote from: thenakedscientists.com
ēThe site is not for the promotion of business interests, or other personal ventures.
http://www.thenakedscientists.com/forum/index.php?action=register      [ You'll need to logout for this link to work ]

I believe you could set up a webpage to espouse your theory which did not contain any adverts/links for your unproven products and be permitted post a link to that webpage in this forum, i.e. your opinion isn't censored but adverts for your products are , ( NB: Iím not a moderator in this forum ).
« Last Edit: 04/11/2013 20:38:09 by RD »
 

Offline Zapper Dave

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Re: Killing bacteria with low voltage science fair project
« Reply #4 on: 04/11/2013 21:47:10 »
Some good points RD

Your claim: The voltages used in High energy Pulsed Electric Fields ( PEF ) used to sterilize liquid foodstufs would be more than sufficient to rupture blood cells

Is unfounded in relationship to this post. The quoted studies are mostly low voltage, low current and do not damage the cells of higher organisms.

 I didnít introduce "High energy Pulsed Electric Fields" to this thread : you mention "High energy Pulsed Electric Fields" in the opening line of your first post.
Yes, I agree, but if you continued to read the introduction, I said "Current literature on the subject explains that lower voltages can be used if the number of pulses is increased "

All of the links supplied discuss various methods of applying lower voltages to kill various microbes.


visually illustrates that low voltage ( less than 10 volts ), low current ( less than 10.0 ma ) can very effectively kill many microbes when applied over a reasonable time ( 1 hour ) ...

Assuming your experiment is as you describe, a possible alternative explanation is that passing 10 Volts at 10mA across the (copper?) electrodes dunked into the jar has changed the chemistry of the water which has made it toxic for the things which were previously living there , i.e. newbielink:https://en.wikipedia.org/wiki/Electrolysis [nonactive]. If the life in the jar is extinguished if you put the electrodes against the outside of the jar then that would support your claim that the applied electric field is directly killing the occupants.

3 problems here, First, I did not use copper. Three different tests were done using brass ( yes, some possible copper contamination ), stainless steel, and aluminum. I expect to do it again with titanium and platinum.

The second issue is that when the same brass electrodes were used with direct connection to the battery ( not pulsed ) many microbes survived despite almost 3 times as much copper transported.

Also, since glass is a significant insulator, it would effectively block any current if the electrodes were externally applied.

It is unfair to delete the links of someone because of claims that they might have unfounded information and then refute with unfounded claims.

The link deleted was to your own commercial site where you sell products , so effectively an advertisement , plugging your own products via such links is not permitted in this forum ...

The only product sold there is a book.

Quote from: thenakedscientists.com
ēThe site is not for the promotion of business interests, or other personal ventures.
http://www.thenakedscientists.com/forum/index.php?action=register      [ You'll need to logout for this link to work ]

I believe you could set up a webpage to espouse your theory which did not contain any adverts/links for newbielink:http://www.fda.gov/ICECI/EnforcementActions/WarningLetters/2006/ucm076017.htm [nonactive] and be permitted post a link to that webpage in this forum, i.e. your opinion isn't censored but adverts for your products are , ( NB: Iím not a moderator in this forum ).

Does not matter to me that the link was removed per se except that it provides technical information that is pertinent to the topic. As I said, I am not here to promote the business interests but to expose the truth. The truth is that low voltage low current pulsed electrical fields can be used to kill bacteria, protozoa, fungi, and some other microbial organisms.

Also, pure DC is effective against some microbes but possibly not against others.

Also, different frequencies appear to affect different sets of microbes.

There are many studies needed.

Which frequencies are best for which microbes?
Is the slew rate of the waveform important?
How important is the duty cycle?
What is the minimum effective peak voltage at any specific frequency?
Also, what sine wave frequencies are effective against a particular microbe? There is a Rife Frequency CAFL list available, but it is not known just how accurate it is.

The point that I do want to make is that by someone doing a science fair project to clear up some of these questions, that person may be contributing to saving lives from horrible deaths due to sepsis and septicemia.
 

Offline CliffordK

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Re: Killing bacteria with low voltage science fair project
« Reply #5 on: 04/11/2013 22:31:15 »
How are you delivering the power?

You skin has a resistance of about 3,000 Ω (at 25V), and your total body resistance might be as high as 100,000 Ω.

Applied internally, even low voltage of 9V, and perhaps 100mA can be lethal to humans.  Even currents down to 10mA can be dangerous. 

See Wikipedia, Yahoo Answers, and Electric Shock QA

To get a good comparison between pulses applied to your skin, and pulses with electrodes in your jar, you should probably add a 10kΩ resistor to your circuit.
 

Offline RD

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Re: Killing bacteria with low voltage science fair project
« Reply #6 on: 04/11/2013 23:21:36 »
... 3 problems here, First, I did not use copper [electrodes]. Three different tests were done using brass ( yes, some possible copper contamination ), stainless steel, and aluminum. I expect to do it again with titanium and platinum.

Platinum or carbon electrodes are usually in electrolysis experiments. However even with inert electrodes the current will still change the chemical composition of the water when a voltage above 1.5V is applied ...

Quote from: lsbu.ac.uk
Electrolysis of water
Generally the water next to the electrodes will change pH due to the ions produced or consumed.
http://www.lsbu.ac.uk/water/electrolysis.html#intro

 Adding pH indicator to your water will show colour changes if the pH changes.

How important is the duty cycle?
The chemical change is proportional to the total amount of current passed through the water.

What is the minimum effective peak voltage ...
To electrolyse water the voltage must be above 1.5 Volts

https://en.wikipedia.org/wiki/Electrolysis_of_water
« Last Edit: 04/11/2013 23:51:06 by RD »
 

Offline Zapper Dave

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Re: Killing bacteria with low voltage science fair project
« Reply #7 on: 05/11/2013 00:42:21 »
Hi Clifford,

Basically, this application is actually for water treatment uses rather than for human use. For this reason, we are pulsing the power supplied by a 9 volt Duracell battery through the device and electrodes which are in direct contact with the water being tested.

How are you delivering the power?

You skin has a resistance of about 3,000 Ω (at 25V), and your total body resistance might be as high as 100,000 Ω.

Applied internally, even low voltage of 9V, and perhaps 100mA can be lethal to humans.  Even currents down to 10mA can be dangerous. 

See newbielink:http://en.wikipedia.org/wiki/Electric_shock#Pathophysiology [nonactive], newbielink:http://answers.yahoo.com/question/index?qid=20100824225158AAwBFOU [nonactive], and newbielink:http://www.highvoltageconnection.com/articles/ElectricShockQuestions.htm [nonactive]

To get a good comparison between pulses applied to your skin, and pulses with electrodes in your jar, you should probably add a 10kΩ resistor to your circuit.

Skin resistance does vary but is inversely proportional to the surface contact area. This area can range from 1 inch square to over 30 inch square, depending on the electrodes used. Also, since our users place a paper towel, wet with salt water between the skin and electrodes, they can achieve very low resistance.

The devices, however, have an active current limiting device on the output which limits the max DC current to about 9.0 to 9.5 ma.
 

Offline Zapper Dave

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Re: Killing bacteria with low voltage science fair project
« Reply #8 on: 05/11/2013 00:57:29 »
... 3 problems here, First, I did not use copper [electrodes]. Three different tests were done using brass ( yes, some possible copper contamination ), stainless steel, and aluminum. I expect to do it again with titanium and platinum.

Platinum or newbielink:https://en.wikipedia.org/wiki/File:Electrolysis.svg [nonactive] electrodes are usually in electrolysis experiments. However even with inert electrodes the current will still change the chemical composition of the water when a voltage above 1.5V is applied ...
Most importantly, in our main targeted application, controlling biofilm in cooling towers, this chemical change is of minimum concern because these units are replacing heavy chemical germicidal application.
Quote from: lsbu.ac.uk
Electrolysis of water
Generally the water next to the electrodes will change newbielink:https://en.wikipedia.org/wiki/PH [nonactive] due to the ions produced or consumed.
newbielink:http://www.lsbu.ac.uk/water/electrolysis.html#intro [nonactive]

 Adding newbielink:https://en.wikipedia.org/wiki/PH_Indicator [nonactive] to your water will show colour changes if the pH changes.
In our case, as you can see from the control jar, coloration and cloudiness will affect the pH indicator. For this purpose, we monitor the pH and the conductivity of the water with probes.
How important is the duty cycle?
The chemical change is proportional to the total amount of current passed through the water.
Ahhh! Yes, but the chemical change is not proportional to the anti-microbial effect.

For example, in the test that was applied to the jars shown above, The duty cycle was 50 percent, the voltage was 9.2 volts, and the duration was 2 hours. The microbial reduction was greater than 99.9 percent.

As a comparison, another separate test was run on an identical sample from the same pond water. The duty cycle was 100 percent ( direct DC ), the voltage was 9.4, and the duration was 2.75 hours total. The microbial reduction, however was only about 40 percent.

What is the minimum effective peak voltage ...
To electrolyse water the voltage must be above 1.5 Volts

newbielink:https://en.wikipedia.org/wiki/Electrolysis_of_water [nonactive]
 

Offline RD

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Re: Killing bacteria with low voltage science fair project
« Reply #9 on: 05/11/2013 08:39:11 »
Most importantly, in our main targeted application, controlling biofilm in cooling towers, this chemical change is of minimum concern because these units are replacing heavy chemical germicidal application.

It looks like the chemical change is responsible for germicide , so it is important rather than negligible.

BTW if your application involves metal structures you may want to read up on cathodic protection : applying electricity to a metal structure can cause it to corrode faster or slower.

In our case, as you can see from the control jar, coloration and cloudiness will affect the pH indicator. For this purpose, we monitor the pH and the conductivity of the water with probes.

It's not too cloudy to observe colour change, adding a dash of universal indicator would show two different colour changes at the two electrodes if electrolysis was occurring, ( cheaper than a pH meter ).

... the chemical change is not proportional to the anti-microbial effect.

For example, in the test that was applied to the jars shown above, The duty cycle was 50 percent, the voltage was 9.2 volts, and the duration was 2 hours. The microbial reduction was greater than 99.9 percent.

As a comparison, another separate test was run on an identical sample from the same pond water. The duty cycle was 100 percent ( direct DC ), the voltage was 9.4, and the duration was 2.75 hours total. The microbial reduction, however was only about 40 percent.

You're making conclusions from one experiment which involves biology  :(
You'd have to repeat this experiment a hundred times to be confident there is frequency-dependence, ( even then it could be due to a physical mixing effect by alternating the polarity of the electrodes , rather than the biology being frequency specific ).
« Last Edit: 05/11/2013 08:51:52 by RD »
 

Offline Zapper Dave

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Re: Killing bacteria with low voltage science fair project
« Reply #10 on: 05/11/2013 19:11:01 »
Most importantly, in our main targeted application, controlling biofilm in cooling towers, this chemical change is of minimum concern because these units are replacing heavy chemical germicidal application.

It looks like the chemical change is responsible for germicide , so it is important rather than negligible.

If it was the chemical change, then the DC test would have produced as good of results as the pulsed electric field test and it did not. If you read the studies provided, they have previously shown that the PEF is in itself effective beyond what DC can produce.

BTW if your application involves metal structures you may want to read up on newbielink:https://en.wikipedia.org/wiki/Cathodic_protection#Impressed_current_systems [nonactive] : applying electricity to a metal structure can cause it to corrode faster or slower.

Good point and definitely a consideration. We are aware of this, however, the current applied is so low that over a long period of time, there is minimal corrosion apparent. We generally do not use the metal of the structure as an electrode but instead use separate electrodes suspended in the water.

In our case, as you can see from the control jar, coloration and cloudiness will affect the pH indicator. For this purpose, we monitor the pH and the conductivity of the water with probes.

It's not too cloudy to observe colour change, adding a dash of newbielink:https://en.wikipedia.org/wiki/Universal_indicator [nonactive] would show two different colour changes at the two electrodes if electrolysis was occurring, ( cheaper than a pH meter ).

Perhaps I am a bit pick about this but I still remain concerned that the green color of the chlorophyll can alter the visual determination of pH. That aside, even if the pH were to change at either the Anode or at the Cathode, this still does not explain that the microbes are killed throughout the jar. We used the pH meter, because we already had it.

... the chemical change is not proportional to the anti-microbial effect.

For example, in the test that was applied to the jars shown above, The duty cycle was 50 percent, the voltage was 9.2 volts, and the duration was 2 hours. The microbial reduction was greater than 99.9 percent.

As a comparison, another separate test was run on an identical sample from the same pond water. The duty cycle was 100 percent ( direct DC ), the voltage was 9.4, and the duration was 2.75 hours total. The microbial reduction, however was only about 40 percent.

You're making conclusions from one experiment which involves biology  :(
You'd have to repeat this experiment a hundred times to be confident there is frequency-dependence, ( even then it could be due to newbielink:https://en.wikipedia.org/wiki/Electrophoresis [nonactive] , rather than the biology being frequency specific ).

We have been repeating this test and others many times over the last 14 years. The results have been consistent. We have also produced the same results under microscopic observation and have shown that many of the microbes literally explode within minutes after the signal is applied, long before any chemical changes become apparent.

We have also done similar tests on bread that has been exposed and then LVPEF applied with significantly reduced growth of mold and bacteria.

We have even done this test with meat, sliced, exposed, and then LVPEF applied with reduced bacterial growth and delayed spoilage.

 

Offline RD

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Re: Killing bacteria with low voltage science fair project
« Reply #11 on: 05/11/2013 20:36:19 »
Ö even if the pH were to change at either the Anode or at the Cathode, this still does not explain that the microbes are killed throughout the jar Ö

The chemical products are formed at the electrodes , so are more concentrated there, but are not confined there : they will diffuse throughout the water in the jar.

Hereís an experiment which would determine if the electricity or the chemical change in the water caused by the electricity is responsible for the germicide. Perform the experiment without any micro-organisms in the water, (10Volt 10mA 2 hours ). Then switch off the power and try to culture micro-organisms in the electrolysed water. If electrolysed water is less hospitable to the micro-organisms than untreated water then you know it is chemical change which is the germicide , not the electric field killing the microbes directly.
« Last Edit: 05/11/2013 20:43:42 by RD »
 

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Re: Killing bacteria with low voltage science fair project
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