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Molecular basis of water proton relaxation in gels and tissue

Vaca Chavez, Fabian LU and Halle, Bertil LU (2006) In Magnetic Resonance in Medicine 56(1). p.73-81
Abstract
An extensive set of water-H magnetic relaxation dispersion (MRD) data are presented for aqueous agarose and gelatin gels. It is demonstrated that the EMOR model, which was developed in a companion paper to this study (see Halle, this issue), accounts for the dependence of the water-H spin-lattice relaxation rate on resonance frequency over more than four decades and on pH. The parameter values deduced from analysis of the H-1 MRD data are consistent with values derived from H-2 MRD profiles from the same gels and with small-molecule reference data. This agreement indicates that the water-H-1 relaxation dispersion in aqueous biopolymer gels is produced directly by exchange-mediated orientational randomization of internal water molecules or... (More)
An extensive set of water-H magnetic relaxation dispersion (MRD) data are presented for aqueous agarose and gelatin gels. It is demonstrated that the EMOR model, which was developed in a companion paper to this study (see Halle, this issue), accounts for the dependence of the water-H spin-lattice relaxation rate on resonance frequency over more than four decades and on pH. The parameter values deduced from analysis of the H-1 MRD data are consistent with values derived from H-2 MRD profiles from the same gels and with small-molecule reference data. This agreement indicates that the water-H-1 relaxation dispersion in aqueous biopolymer gels is produced directly by exchange-mediated orientational randomization of internal water molecules or labile biopolymer protons, with little or no role played by collective biopolymer vibrations or coherent spin diffusion. This ubiquitous mechanism is proposed to be the principal source of water-H-1 spin-lattice relaxation at low magnetic fields in all aqueous systems with rotationally immobile biopolymers, including biological tissue. The same mechanism also contributes to transverse and rotating-frame relaxation and magnetization transfer at high fields. (Less)
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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
agarose, proton exchange, internal water, dispersion, magnetic relaxation, gelatin
in
Magnetic Resonance in Medicine
volume
56
issue
1
pages
73 - 81
publisher
John Wiley and Sons
external identifiers
  • wos:000238823600009
  • pmid:16732591
  • scopus:33745727912
ISSN
1522-2594
DOI
10.1002/mrm.20912
language
English
LU publication?
yes
id
e2f95b46-5d3b-470d-8c10-c50a982838bf (old id 403944)
date added to LUP
2016-04-01 12:14:25
date last changed
2021-10-06 01:41:54
@article{e2f95b46-5d3b-470d-8c10-c50a982838bf,
  abstract     = {An extensive set of water-H magnetic relaxation dispersion (MRD) data are presented for aqueous agarose and gelatin gels. It is demonstrated that the EMOR model, which was developed in a companion paper to this study (see Halle, this issue), accounts for the dependence of the water-H spin-lattice relaxation rate on resonance frequency over more than four decades and on pH. The parameter values deduced from analysis of the H-1 MRD data are consistent with values derived from H-2 MRD profiles from the same gels and with small-molecule reference data. This agreement indicates that the water-H-1 relaxation dispersion in aqueous biopolymer gels is produced directly by exchange-mediated orientational randomization of internal water molecules or labile biopolymer protons, with little or no role played by collective biopolymer vibrations or coherent spin diffusion. This ubiquitous mechanism is proposed to be the principal source of water-H-1 spin-lattice relaxation at low magnetic fields in all aqueous systems with rotationally immobile biopolymers, including biological tissue. The same mechanism also contributes to transverse and rotating-frame relaxation and magnetization transfer at high fields.},
  author       = {Vaca Chavez, Fabian and Halle, Bertil},
  issn         = {1522-2594},
  language     = {eng},
  number       = {1},
  pages        = {73--81},
  publisher    = {John Wiley and Sons},
  series       = {Magnetic Resonance in Medicine},
  title        = {Molecular basis of water proton relaxation in gels and tissue},
  url          = {http://dx.doi.org/10.1002/mrm.20912},
  doi          = {10.1002/mrm.20912},
  volume       = {56},
  year         = {2006},
}