Application of paramagnetically tagged molecules for magnetic resonance imaging of biofilm mass transport processes

B. Ramanan, W. M. Holmes, W. T. Sloan, V. R. Phoenix

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Molecules become readily visible by magnetic resonance imaging (MRI) when labeled with a paramagnetic tag. Consequently, MRI can be used to image their transport through porous media. In this study, we demonstrated that this method could be applied to image mass transport processes in biofilms. The transport of a complex of gadolinium and diethylenetriamine pentaacetic acid (Gd-DTPA), a commercially available paramagnetic molecule, was imaged both in agar (as a homogeneous test system) and in a phototrophic biofilm. The images collected were T1 weighted, where T1 is an MRI property of the biofilm and is dependent on Gd-DTPA concentration. A calibration protocol was applied to convert T1 parameter maps into concentration maps, thus revealing the spatially resolved concentrations of this tracer at different time intervals. Comparing the data obtained from the agar experiment with data from a one-dimensional diffusion model revealed that transport of Gd-DTPA in agar was purely via diffusion, with a diffusion coefficient of 7.2 X 10-10 m2 s-1. In contrast, comparison of data from the phototrophic biofilm experiment with data from a two-dimensional diffusion model revealed that transport of Gd-DTPA inside the biofilm was by both diffusion and advection, equivalent to a diffusion coefficient of 1.04 × 10 -9 m2 s-1. This technology can be used to further explore mass transport processes in biofilms, either by using the wide range of commercially available paramagnetically tagged molecules and nanoparticles or by using bespoke tagged molecules.

LanguageEnglish
Pages4027-4036
Number of pages10
JournalApplied and Environmental Microbiology
Volume76
Issue number12
Early online date30 Apr 2010
DOIs
Publication statusPublished - 15 Jun 2010
Externally publishedYes

Fingerprint

soil transport processes
Biofilms
mass transport
mass transfer
transport process
magnetic resonance imaging
biofilm
gadolinium
Pentetic Acid
DTPA
Magnetic Resonance Imaging
Gadolinium
agar
Agar
acids
diffusivity
nanoparticles
porous media
Nanoparticles
Calibration

Keywords

  • magnetic resonance imaging
  • MRI
  • paramagnetic tag
  • biofilm
  • parameter maps
  • concentration maps

Cite this

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Application of paramagnetically tagged molecules for magnetic resonance imaging of biofilm mass transport processes. / Ramanan, B.; Holmes, W. M.; Sloan, W. T.; Phoenix, V. R.

In: Applied and Environmental Microbiology, Vol. 76, No. 12, 15.06.2010, p. 4027-4036.

Research output: Contribution to journalArticle

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