Is Acanthamoeba Castellanii sensitive to magnetic fields?

Abstract

 

Purpose

 

To determine if Acanthamoeba Castellanii (A. Castellanii) exhibits attraction or repulsion towards a magnetic field (as it does in the presence of an electric field, Rudell et al, IOVS 2013) so as it would potentially be possible to draw them out to the corneal surface via a magnetic contact lens.

 

Methods

 

A placeholder was constructed from acrylic material (7.5”x6.5”x0.5”) to tightly house (non-nutrient agar) petri dish and a powerful (20G) cylindrical rare earth magnet (Riley, 0.25”x2”). A solution of A. Castellanii containing both cysts and trophozoite was formulated to a concentration of 9.3x10⁴. Thereafter, 2 milliliters of solution were added to the petri dish and spread evenly over the entire surface with the excess solution decanted. Using a permanent marker, the petri dish was marked 1cm from the face of the rare earth magnet within the placeholder. Subsequently, images of A. Castellanii where taken within 1cm of rare earth magnet using an inverted, Nikon Diaphot, microscope fixed at 20x magnification, to monitor A. Castellanii movement over a one-hour period. For the first 20 minutes A. Castellanii was monitored without any magnetic field. Subsequently, rare earth magnet was positioned in placeholder and A. Castellanii was directed at the South Pole of the rare earth magnet. Finally, for the remaining 20 minutes the poles of the magnet was reversed and A. Castellanii was directed at the North Pole of the rare earth magnet. Images where taken every 10 minutes and A. Castellanii movement was assessed by trophozoite and cyst displacement within picture using applied scaled gridlines.

 

Results

 

A. Castellanii displayed motion. However, over the one-hour interval, neither cysts nor trophozoite displayed significant or quantitative displacement, within applied gridlines, towards either pole of the rare earth magnet. Minor movement of A. Castellanii seen within gridlines, can be deemed random.

 

Conclusions

 

Previous studies have shown that A. Castellanii attracts and repels with respect to an electric field, while this pilot study shows A. Castellanii does not attract nor repel in response to the magnetic field produced by a (20G) rare earth magnet.

 

 

Figure 1: A. Castellanii with no magnetic field.

 

 

Figure 2: A. Castellanii directed at south pole of rare earth magnet. *(N(+)/S(-) INDICATE POSITION OF MAGNET)

 

Keywords: 402 Acanthamoeba • 594 microbial pathogenesis: experimental studies