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Magnetic resonance imaging (MRI) of heavy-metal transport and fate in an artificial biofilm

Published online by Cambridge University Press:  05 July 2018

V. R. Phoenix ,
W. M. Holmes  and
B. Ramanan
V. R. Phoenix*
Affiliation:
Department of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK
W. M. Holmes
Affiliation:
7T MR Facility, Wellcome Surgical Institute, University of Glasgow, Glasgow G61 1QH, UK
B. Ramanan
Affiliation:
Department of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK
*
*E-mail: [email protected]
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Abstract

Unlike planktonic systems, reaction rates in biofilms are often limited by mass transport, which controls the rate of supply of contaminants into the biofilm matrix. To help understand this phenomenon, we investigated the potential of magnetic resonance imaging (MRI) to spatially quantify copper transport and fate in biofilms. For this initial study we utilized an artificial biofilm composed of a 50:50 mix of bacteria and agar. MRI successfully mapped Cu2+ uptake into the artificial biofilm by mapping T2 relaxation rates. A calibration protocol was used to convert T2 values into actual copper concentrations. Immobilization rates in the artificial biofilm were slow compared to the rapid equilibration of planktonic systems. Even after 36 h, the copper front had migrated only 3 mm into the artificial biofilm and at this distance from the copper source, concentrations were very low. This slow equilibration is a result of (1) the time it takes copper to diffuse over such distances and (2) the adsorption of copper onto cell surfaces, which further impedes copper diffusion. The success of this trial run indicates MRI could be used to quantitatively map heavy metal transport and immobilization in natural biofilms.

Type
Research Article
Information
Mineralogical Magazine , Volume 72 , Issue 1 , February 2008 , pp. 483 - 486
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2008

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