A Radio Frequency Electric Current Enhances Antibiotic Efficacy against Bacterial Biofilms

ABSTRACT Bacterial biofilms are notably resistant to antibiotic prophylaxis. The concentration of antibiotic necessary to significantly reduce the number of bacteria in the biofilm matrix can be several hundred times the MIC for the same bacteria in a planktonic phase. It has been observed that the addition of a weak continuous direct electric current to the liquid surrounding the biofilm can dramatically increase the efficacy of the antibiotic. This phenomenon, known as the bioelectric effect, has only been partially elucidated, and it is not certain that the electrical parameters are optimal. We confirm here the bioelectric effect for Escherichia coli biofilms treated with gentamicin and with oxytetracycline, and we report a new bioelectric effect with a radio frequency alternating electric current (10 MHz) instead of the usual direct current. None of the proposed explanations (transport of ions within the biofilm, production of additional biocides by electrolysis, etc.) of the direct current bioelectric effect are applicable to the radio frequency bioelectric effect. We suggest that this new phenomenon may be due to a specific action of the radio frequency electromagnetic field upon the polar parts of the molecules forming the biofilm matrix.

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The Isotope Effect of a Direct Electric Current through Liquid and Solid Metals

Zeitschrift für Naturforschung A ◽

10.1515/zna-1956-0112 ◽

1956 ◽

Vol 11 (1) ◽

pp. 71-75

Author(s):

E. Haeffner ◽

Th. Sjöborg ◽

S. Lindhe

Keyword(s):

Liquid Metal ◽

Electric Current ◽

Isotope Effect ◽

Direct Current ◽

Capillary Tube ◽

Isotope Separation ◽

Direct Electric Current ◽

Separation Effect ◽

A Current

The isotope separation effect of a direct electric current in a liquid metal is demonstrated by passing a current through mercury, which is enclosed in a capillary tube. The second part of the paper deals with an attempt of establishing an isotope effect when a direct current is passed through an uranium wire.

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The impact of titanium oxide nanoparticles and low direct electric current on biofilm dispersal of $Bacillus~cereus$ and $Pseudomonas~aeruginosa$: A comparative study

Papers in Physics ◽

10.4279/pip.130005 ◽

2021 ◽

Vol 13 ◽

pp. 130005

Author(s):

Mamdouh M. Shawki ◽

Marwa M. Eltarahony ◽

Maisa E. Moustafa

Keyword(s):

Pseudomonas Aeruginosa ◽

Bacillus Cereus ◽

Electric Current ◽

Titanium Oxide ◽

Cell Surface Hydrophobicity ◽

Bacterial Biofilms ◽

Direct Electric Current ◽

Wide Range ◽

The Impact ◽

Scanning Electron

Bacteria growing in biofilms cause a wide range of environmental, industrial and public health risks. Because biofilm bacteria are very resistant to antibiotics, there is an urgent need in medicine and industry to develop new approaches to eliminating bacterial biofilms. One strategy for controlling these biofilms is to generate an antibiofilm substance locally at the attachment surface. Direct electric current (DC) and nanoparticles (NPs) of metal oxides have outstanding antimicrobial properties. In this study we evaluated the effect of titanium oxide nanoparticle (TiO$_2$-NP) concentrations from 5 to 160 $\mu$g/mL on Bacillus cereus and Pseudomonas aeruginosa biofilms, and compared this with the effect of a 9 V, 6 mA DC electric field for 5, 10 and 15 min. TiO$_2$-NPs were characterized using transmission and scanning electron microscopes, X-ray diffraction and FTIR. They exhibited an average size of 22-34 nm. The TiO$_2$-NP concentrations that attained LD50 were $104 \pm 4$ $\mu$g/mL and $63 \pm 3$ $\mu$g/mL for B. cereus and P. aeruginosa, respectively. The eradication percentages obtained by DC at 5, 10, and 15 min exposure were 21%, 29%, and 33% respectively for B. cereus and 30%, 39%, and 44% respectively for P. aeruginosa. Biofilm disintegration was verified by exopolysaccharide, protein content and cell surface hydrophobicity assessment, as well as scanning electron microscopy. These data were correlated with the reactive oxygen species produced. The results indicated that both DC and TiO$_2$-NPs have a lethal effect on these bacterial biofilms, and that the DC conditions used affect the biofilms in a similar way to TiO$_2$-NPs at concentrations of 20-40 $\mu$g/mL.

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Studies of excitation modes of thermoacoustic emitters of sound – of thermophones

MORSKIE INTELLEKTUAL`NYE TEHNOLOGII ◽

10.37220/mit.2020.50.4.058 ◽

2020 ◽

pp. 164-168

Author(s):

Ф.Ф. Легуша ◽

Н.С. Григорьева ◽

В.Д. Лукьянов ◽

К.В. Разрезова ◽

А.В. Троицкий

Keyword(s):

Electric Current ◽

Active Element ◽

Acoustic Radiation ◽

Radiation Power ◽

Electrical Power ◽

Sound Waves ◽

Radiation Level ◽

Direct Electric Current ◽

Excitation Mode ◽

Alternating Electric Current

В работе проведён анализ влияния режимов возбуждения термофона на его акустическую эффективность. В настоящее время для возбуждения современных термофонов используют два режима возбуждения соответствующих случаям, когда в активном элементе термофона текут: 1) постоянный электрический ток I0 и переменный электрический ток i(f) = Imsin(ωt); 2) только переменный ток i(f) = Imsin(ωt). В этих случаях термофон излучает звуковые волны, амплитуды колебательных скоростей которых um1 и um2 соответствуют номерам режимов. При этом показано, если выполняется неравенство I0 >> Im, то отношение колебательных скоростей um1 / um2 ≥ 28. Как следствие этого, уровень излучения звука при 1 режиме возбуждения более чем на 29 дБ выше, а мощность акустического излучения в 860 раз выше по сравнению со вторым режимом возбуждения. Таким образом, для создания мобильных эхолокационных систем, работающих в газах, могут быть использованы термофоны, в которых реализован первый режим возбуждения, имеющий более сложную схему электрического питания. The paper analyzes the influence of thermophone excitation modes on its acoustic efficiency. Currently, to excite modern thermophones, two excitation modes are used corresponding to cases when in the active element of the thermophone flows: 1) direct electric current I0 and alternating electric current i(f) = Imsin(ωt); 2) only alternating current i(f) = Imsin(ωt). In these cases, the thermophone emits sound waves whose vibrational speed amplitudes um1 and um2 correspond to the mode numbers. It is shown that if the inequality I0 >> Im, is satisfied, then the ratio of vibrational speeds um1 / um2 ≥ 28. As a result, the sound radiation level at 1 excitation mode is more than 29 dB higher, and the acoustic radiation power is 860 times higher compared to the second excitation mode. Thus, to create mobile echolocation systems operating in gases, thermophones can be used, in which the first excitation mode is implemented, which has a more complex electrical power supply scheme.

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Bacterial biofilms and the bioelectric effect.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.40.9.2012 ◽

1996 ◽

Vol 40 (9) ◽

pp. 2012-2014 ◽

Cited By ~ 64

Author(s):

N Wellman ◽

S M Fortun ◽

B R McLeod

Keyword(s):

Direct Current ◽

Antibacterial Agent ◽

Industrial Processes ◽

Maximum Effect ◽

Bacterial Biofilms ◽

Bioelectric Effect ◽

Direct Current Electric Field ◽

Sterilization Process ◽

Current Electric Field ◽

A Current

Bacterial biofilms are acknowledged to be a major factor in problems of ineffective sterilization often encountered in clinics, hospitals, and industrial processes. There have been indications that the addition of a relatively small direct current electric field with the sterilant used to combat the biofilm greatly increases the efficacy of the sterilization process. The results of the experiments reported in this paper support the concept of the "bioelectric effect" as reported by J.W. Costerton, B. Ellis, K. Lam, F. Johnson, and A.E. Khoury (Antimicrob. Agents Chemother, 38:2803-2809, 1994). With a current of 1 mA flowing through the chamber containing the biofilm, an increase in the killing of the bacteria of about 8 log orders was observed at the end of 24 h (compared with the control with the same amount of antibacterial agent but no current). We also confirmed that the current alone does not affect the biofilm and that there appear to be optimum levels of both the current and the sterilant that are needed to obtain the maximum effect.

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Charge carriers drift induced THz amplification in dual-layer graphene structure

Journal of Physics Conference Series ◽

10.1088/1742-6596/2015/1/012094 ◽

2021 ◽

Vol 2015 (1) ◽

pp. 012094

Author(s):

I.M. Moiseenko ◽

V.V. Popov ◽

D.V. Fateev

Keyword(s):

Electric Current ◽

Direct Current ◽

Spatial Dispersion ◽

Charge Carriers ◽

Frequency Range ◽

Direct Electric Current ◽

The Real ◽

Layer Graphene

Abstract The terahertz plasmon amplification in structure based on graphene with spatial dispersion of its hydrodynamic conductivity is investigated theoretically. The spatial dispersion of graphene conductivity is related to accounting of charge carriers pressure forces and direct current in graphene. It was shown that the real part of graphene conductivity becomes negative at THz frequency range due to direct electric current in graphene.

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Stimulation of Osteogenesis by Direct Electric Current (Review)

Traumatology and Orthopedics of Russia ◽

10.21823/2311-2905-2019-25-3-185-191 ◽

2019 ◽

Vol 25 (3) ◽

pp. 185-191

Author(s):

E. N. Ovchinnikov ◽

M. V. Stogov

Keyword(s):

Stem Cells ◽

Electric Current ◽

Direct Current ◽

English Language ◽

Direct Electric Current ◽

Metal Implants ◽

Electromagnetic Stimulation ◽

Analytical Review ◽

Differentiation And Proliferation ◽

Stimulation Of

Background. Stimulation of osteogenesis in the treatment of certain orthopedic and trauma pathologies is a necessary element to ensure the best clinical outcome. The purpose of the present analytical review is to analyze the literature data in respect of evaluating the approaches and possibilities to stimulate osteogenesis using direct current. Methods. The search for literature data was performed in the open electronic databases of scientific literature PubMed and eLIBRARY under the following keywords and their combinations: “osteogenesis”, “reparative osteogenesis”, “direct electric current”, “orthopaedics”, “traumatology”, “electric current” (in Russian as well as in English language ). Results. According to some fundamental research, the stimulating effect of direct current lies is both in stimulating differentiation and proliferation of osteoblasts, and in stimulating differentiation of stem cells, mainly mesenchymal stem cells of bone marrow and adipose tissue, in the process of osteogenesis. The following stimulating technologies were developed and clinically tested to date: 1 — direct exposure of bone to the direct current; 2 — capacitive coupled stimulation; and 3 — inductive coupled (electromagnetic) stimulation. Analysis of clinical practice demonstrated that the first technology is most effective in terms of osteoreparation, but less safe than technology 2 and 3. It should be noted that there are no clear indications and modes of application for the abovementioned methods. Based on the data collected in the present analysis, technology 1 is considered by authors as the most promising. Safety of technology 1 can be enhanced by application of metal implants as electrodes in case those are planned to be used for medical reasons: wires, rods, staples, fixators, etc. Conclusion. Use of electric current to stimulate bone formation is a promising method which requires clarification in respect of indications and application modes.

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Electrolytic Generation of Oxygen Partially Explains Electrical Enhancement of Tobramycin Efficacy againstPseudomonas aeruginosa Biofilm

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.43.2.292 ◽

1999 ◽

Vol 43 (2) ◽

pp. 292-296 ◽

Cited By ~ 55

Author(s):

Philip S. Stewart ◽

Wanida Wattanakaroon ◽

Lu Goodrum ◽

Susana M. Fortun ◽

Bruce R. McLeod

Keyword(s):

Electric Current ◽

Sodium Thiosulfate ◽

Reactive Oxygen ◽

Viable Cell ◽

Positive Control ◽

Reactive Oxygen Intermediates ◽

Oxygen Intermediates ◽

Gaseous Oxygen ◽

Bioelectric Effect ◽

Antibiotic Efficacy

ABSTRACT The role of electrolysis products, including protons, hydroxyl ions, reactive oxygen intermediates, oxygen, hydrogen, and heat, in mediating electrical enhancement of killing of Pseudomonas aeruginosa biofilms by tobramycin (the bioelectric effect) was investigated. The log reduction in biofilm viable cell numbers compared to the numbers for the untreated positive control effected by antibiotic increased from 2.88 in the absence of electric current to 5.58 in the presence of electric current. No enhancement of antibiotic efficacy was observed when the buffer composition was changed to simulate the reduced pH that prevails during electrolysis. Neither did stabilization of the pH during electrical treatment by increasing the buffer strength eliminate the bioelectric effect. The temperature increase measured in our experiments, less than 0.2°C, was far too small to account for the greatly enhanced antibiotic efficacy. The addition of sodium thiosulfate, an agent capable of rapidly neutralizing reactive oxygen intermediates, did not abolish electrical enhancement of killing. The bioelectric effect persisted when all of the ionic constituents of the medium except the two phosphate buffer components were omitted. This renders the possibility of electrochemical generation of an inhibitory ion, such as nitrite from nitrate, an unlikely explanation for electrical enhancement. The one plausible explanation for the bioelectric effect revealed by this study was the increased delivery of oxygen to the biofilm due to electrolysis. When gaseous oxygen was bubbled into the treatment chamber during exposure to tobramycin (without electric current), a 1.8-log enhancement of killing resulted. The enhancement of antibiotic killing by oxygen was not due simply to physical disturbances caused by sparging the gas because similar delivery of gaseous hydrogen caused no enhancement whatsoever.

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Bioelectric Effect of a Microcurrent Toothbrush on Plaque Removal

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18168255 ◽

2021 ◽

Vol 18 (16) ◽

pp. 8255

Author(s):

Ji-Hyun Lee ◽

Jin-Hee Ha

Keyword(s):

Bacterial Flora ◽

Gingival Index ◽

Direct Electric Current ◽

Plaque Removal ◽

Bioelectric Effect ◽

Biofilm Removal ◽

Significant Difference ◽

The Us ◽

Before And After ◽

Previous State

This study evaluated the effectiveness of a microcurrent toothbrush (approved by the US Food and Drug Administration [FDA]), which employs a superimposed alternating and direct electric current, named as a Proxywave® technology, similar to the intensity of the biocurrent, in plaque removal and reducing gingivitis by biofilm removal through the bioelectric effect. This study enrolled 40 volunteers with gingivitis. Dental observations were made every two weeks, before and after the use of each toothbrush. We randomly assigned participants into two groups: one group used the Proxywave® toothbrush (PB) for two weeks followed by the control toothbrush (CB) for two weeks, while the other group used the CB for two weeks followed by the PB. The participants had a two-week washout period. If the toothbrush used earlier has had an effect on the bacterial flora in the oral cavity, this is to remove this effect and return it to its previous state. During each dental visit, we recorded plaque index (PI) and gingival index (GI) scores. The PI and GI scores were significantly lower in both the PB and the CB (p < 0.05). Considering the PI, there was no significant difference between the toothbrushes on all the surfaces. Considering the GI, the PB showed a significant decrease in the interproximal surface, compared to the CB (p < 0.05). The PB showed a significant decrease in the interproximal GI and had a beneficial effect in the interproximal area where the bristles could not reach. No adverse events were observed in the participants during the clinical trial. The microcurrent toothbrush is a device that can be safely used for plaque removal.

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