Feasibility of heating metal implants with alternating magnetic fields (AMF) in scaled up models

AbstractHundreds of thousands of human implant procedures require surgical revision each year due to infection. Infections are difficult to treat with conventional antibiotics due to the formation of biofilm on the implant surface. We have developed a noninvasive method to eliminate biofilm on metal implants using heat generated by intermittent alternating magnetic fields (iAMF). Here, we demonstrate that heat and antibiotics are synergistic in biofilm elimination. For Pseudomonas aeruginosa biofilm, bacterial burden was reduced >3 log with iAMF and ciprofloxacin after 24 h compared with either treatment alone (p < 0.0001). This effect was not limited by pathogen or antibiotic as similar biofilm reductions were seen with iAMF and either linezolid or ceftriaxone in Staphylococcus aureus. iAMF and antibiotic efficacy was seen across various iAMF settings, including different iAMF target temperatures, dose durations, and dosing intervals. Initial mechanistic studies revealed membrane disruption as one factor important for AMF enhanced antibacterial activity in the biofilm setting. This study demonstrates the potential of utilizing a noninvasive approach to reduce biofilm off of metallic implants.

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Remote acoustic sensing as a safety mechanism during exposure of metal implants to alternating magnetic fields

PLoS ONE ◽

10.1371/journal.pone.0197380 ◽

2018 ◽

Vol 13 (5) ◽

pp. e0197380 ◽

Cited By ~ 4

Author(s):

Bingbing Cheng ◽

Yonatan Chatzinoff ◽

Debby Szczepanski ◽

Chenchen Bing ◽

Sumbul Shaikh ◽

...

Keyword(s):

Magnetic Fields ◽

Acoustic Sensing ◽

Metal Implants ◽

Safety Mechanism ◽

Alternating Magnetic Fields

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315. Alternating Magnetic Fields (AMF) and Antibiotics Eradicate Biofilm on Metal in a Synergistic Fashion

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.511 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S229-S230

Author(s):

Qi Wang ◽

Jonathan Vachon ◽

Christine A Pybus ◽

Sumbul Shaikh ◽

Rajiv Chopra ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Magnetic Fields ◽

Treatment Session ◽

Invasive Approach ◽

Metal Implant ◽

Metal Implants ◽

Non Invasive ◽

Conventional Antibiotics ◽

Alternating Magnetic Fields

Abstract Background Hundreds of thousands of human implant procedures require surgical revision each year due to infection. Implant infections are difficult to treat with conventional antibiotics due to the formation of biofilm on the device surface. We have developed a non-invasive method to treat metal implant infections using alternating magnetic fields (AMF). The outer surface of a metal implant is heated when exposed to AMF, and we hypothesize that this heating can be used to eradicate biofilm or sensitize them to antibiotics (Fig 1). This study investigated the interaction of biofilm and antibiotics in vitro. Fig 1. Scheme showing the principle of AMF treating metal implant infection (MII). Methods P. aeruginosa (PAO1) and Staphylococcus aureus (UAMS1) biofilms were cultured on stainless steel rings. The biofilms were then treated as in Fig 2, receiving a series of AMF exposures every 12 hours. Each dose of AMF was comprised of multiple 3s-AMF exposures every 5 min, with a peak ring temperature of 65 °C. Biofilms were incubated in the presence or absence 0.5 mg/mL ciprofloxacin or ceftriaxone. At the end of 12 and 24 hours, samples were harvested and colony forming units (CFU) were calculated. Fig 2. AMF treatment design. Results AMF alone resulted in a transient decrease in CFU which recovered by the second dose. Antibiotics alone resulted in an ~2-log decrease in CFU at 24 hours. However, the combination of AMF plus cipro showed a synergistic response with a >4-log decrease (Fig 3a). Confocal microscopy confirmed these findings. This effect was not limited to Pseudomonas aeruginosa as similar synergistic responses were seen with Staphylococcus aureus and ceftriaxone (Fig 3b). Fig 3 The bacteria number (CFU) change during 24 hr AMF and antibiotics treatment session. a) P. aeruginosa (PAO1) treated with AMF and ciprofloxacin. b) Staphylococcus aureus (UAMS1) treated with AMF and ceftriaxone. Conclusion When combined with antibiotics, AMF displays a synergistic effect in eradicating biofilm. This effect was seen in different pathogens and in multiple antibiotics. Synergy was seen at different target temperatures as well. This interaction has important implications for deployment of this innovative non-invasive approach to treating biofilm-related infections on metal implants. Disclosures All Authors: No reported disclosures

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Measuring Magnetic Permeability of Monolithic Annular Measures in Alternating Magnetic Fields

Russian Journal of Nondestructive Testing ◽

10.1134/s1061830919110093 ◽

2019 ◽

Vol 55 (11) ◽

pp. 851-857 ◽

Cited By ~ 1

Author(s):

V. A. Syas’ko ◽

S. S. Golubev ◽

Ya. G. Smorodinskii ◽

P. V. Solomenchuk ◽

E. B. Bryukhovetskaya

Keyword(s):

Magnetic Fields ◽

Magnetic Permeability ◽

Alternating Magnetic Fields

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Inactivation of Bacteria Using Bioactive Nanoparticles and Alternating Magnetic Fields

Nanomaterials ◽

10.3390/nano11020342 ◽

2021 ◽

Vol 11 (2) ◽

pp. 342

Author(s):

Vitalij Novickij ◽

Ramunė Stanevičienė ◽

Rūta Gruškienė ◽

Kazimieras Badokas ◽

Juliana Lukša ◽

...

Keyword(s):

Magnetic Fields ◽

Foodborne Pathogens ◽

Morphological Changes ◽

Foodborne Pathogen ◽

Cellular Damage ◽

Suitable Model ◽

Log Reduction ◽

Invasive Infections ◽

Alternating Magnetic Fields ◽

Inactivation Of Bacteria

Foodborne pathogens are frequently associated with risks and outbreaks of many diseases; therefore, food safety and processing remain a priority to control and minimize these risks. In this work, nisin-loaded magnetic nanoparticles were used and activated by alternating 10 and 125 mT (peak to peak) magnetic fields (AMFs) for biocontrol of bacteria Listeria innocua, a suitable model to study the inactivation of common foodborne pathogen L. monocytogenes. It was shown that L. innocua features high resistance to nisin-based bioactive nanoparticles, however, application of AMFs (15 and 30 min exposure) significantly potentiates the treatment resulting in considerable log reduction of viable cells. The morphological changes and the resulting cellular damage, which was induced by the synergistic treatment, was confirmed using scanning electron microscopy. The thermal effects were also estimated in the study. The results are useful for the development of new methods for treatment of the drug-resistant foodborne pathogens to minimize the risks of invasive infections. The proposed methodology is a contactless alternative to the currently established pulsed-electric field-based treatment in food processing.

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