Study type: Medical/biological study (experimental study)

Moderate intensity static magnetic field has bactericidal effect on E. coli and S. epidermidis on sintered hydroxyapatite. med./bio.

Published in: J Biomed Mater Res B Appl Biomater 2012; 100 (5): 1206-1217

Aim of study (acc. to author)

A moderate intensity static magnetic field (100 mT) was applied to understand the bacterial cell adhesion and growth behavior of both gram-positive (Staphylococcus epidermidis) and gram-negative bacteria (Escherichia coli) on a biomaterial surface and also to investigate the bactericidal/bacteriostatic property of the applied magnetic field.

Background/further details

Both sintered hydroxyapatite ceramic and the control samples (glass disc; similar roughness values) seeded with bacteria were exposed to the magnetic field (100 mT) for different durations during logarithmic growth.
Hydroxyapatite is widely known as the most biocompatible and bioactive material among all the synthetic materials. However, one of its major problems is the lack of any antibacterial/bactericidal property. One way to address this problem is the use of an external field, like magnetic field to induce bactericidal/bacteriostatic property.

Endpoint

Exposure

Exposure Parameters
Exposure 1:
Exposure duration: continuous for 30, 60, 120 or 240 min

Exposure 1

Main characteristics
Frequency
Type
Exposure duration continuous for 30, 60, 120 or 240 min
Exposure setup
Exposure source
Setup solenoid consisted of a copper wire (diameter 1.5 mm), coiled into 875 loops; solenoid connected to a DC power supply and placed into an incubator; exposure cavity had a dimension of 17 cm x 15 cm x 4 cm; bacterial suspensions were pipetted on hydroxyapatite or glass discs into a standard plate with four wells, incubated at 37°C and exposed
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 100 mT - measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Quantitative analysis of the scanning electron microscopy images confirmed the inhibitory effect of the static magnetic field on bacterial growth. The results of the cell membrane integrity as well as the ermeability assays further revealed the disintegration of the bacterial cell membrane with the release of the intracellular material upon the magnetic field exposure. Under the investigated culture conditions, the bactericidal effect was found to be less effective for Staphylococcus epidermidis than Escherichia coli.

Study character:

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