Premium
Relaxation induced by ferritin and ferritin‐like magnetic particles: The role of proton exchange
Author(s) -
Gossuin Yves,
Roch Alain,
Muller Robert N.,
Gillis Pierre
Publication year - 2000
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/(sici)1522-2594(200002)43:2<237::aid-mrm10>3.0.co;2-5
Subject(s) - ferritin , proton , relaxation (psychology) , chemistry , relaxometry , nuclear magnetic resonance , range (aeronautics) , dispersion (optics) , chemical physics , materials science , physics , magnetic resonance imaging , nuclear physics , spin echo , biochemistry , medicine , psychology , social psychology , optics , composite material , radiology
Proton T 1 and T 2 in solutions of ferritin and fercayl (a ferritin‐like iron‐dextran particle) solutions were measured, over a wide range of various parameters ( B o , temperature, interecho‐time and pH). The window of the previously referred linear dependence of 1/T 2 on the static field was increased, up to 500 MHz, and the independence of T 2 on the echo time was confirmed. Correlation times were extracted from T 1 nuclear magnetic relaxation dispersion profiles. In the pH range studied, no strong variation of the relaxivities of ferritin solutions was noticed. Fercayl, which, unlike ferritin, remains stable under large pH variations, is characterized by strongly pH‐dependent relaxation rates. This feature is interpreted as due to the effect of proton exchange in the water relaxation process. Outer sphere theory, which ignores proton binding, is shown to be unable to describe the relaxation of ferritin and ferritin‐like particles solutions, first because it predicts a quadratic rate dependence on B o , but also because it severely underestimates the relaxation rate. Explaining relaxation induced by ferritin and ferritin‐like particle solutions will likely require a model that accounts for proton binding. Magn Reson Med 43:237–243, 2000. © 2000 Wiley‐Liss, Inc.