1: Biomaterials  2002 Dec;23(24):4701-4 

Noninvasive in vivo EPR monitoring of the methyl methacrylate polymerization
during the bone cement formation.

Gallez B, Beghein N.

Laboratory of Medicinal Chemistry and Radiopharmacy, Universite catholique de
Louvain, Avenue Mounier 73.40, B-1200 Brussels, Belgium. gallez@cmfa.ucl.ac.be

The curing of poly(methyl methacrylate) (PMMA) bone cement is done by a free
radical polymerization. As the amount of free radicals present is a marker of
the amount of unpolymerized chains present in the polymer, it is assumed that
this could be related to the mechanical properties such as strength or density.
In this study, the direct observation of the free radicals produced during the
PMMA bone cement formation was obtained for the first time in vivo using
low-frequency EPR spectrometers (1.2 GHz). Low frequency permits measurements in
live animals due to the increased microwave penetration. The amount of
polymerization radicals was carried out noninvasively over days on the same
animals. The decay rates obtained in vitro and in vivo were compared: the decay
rates were significantly lower when the curing process occurred in vivo compared
to the situation in vitro. As the kinetics are rather different in vitro and in
vivo, this emphasizes the value of the present method that permits the
noninvasive monitoring of the curing process directly in vivo. Copyright 2002
Elsevier Science Ltd.

PMID: 12361608 [PubMed - in process]