NMR of Tissues Exposed to Polysiloxane Gels
Abstract Silicone (polysiloxanes) gel-filled implants have been widely used for biomedical applications, mainly because they were considered to be nonbiodegradable. However, increasing concern about the health implications of polysiloxane exposure for women with silicone gel-filled breast implants has prompted interest to study the biochemistry of implanted polysiloxanes. The purpose of this work is to investigate the migration of polysiloxanes from the implant to local and distant sites and their chemical modification in living systems. Tissues from animals and humans exposed to polysiloxane gel implants are studied in vivo using proton NMR localized spectroscopy, and in vitro with proton and 29Si magic angle spinning (MAS) NMR spectroscopy. This work demonstrates that free polysiloxanes present in the gel-filled implants migrate to surrounding tissues and distant organs, such as the liver. In addition, 29Si NMR spectra of metabolically active tissues (liver) show the presence of chemically unchanged polysiloxanes and other silicon-containing compounds (silica) which suggest that these polymers are biodegradable.