HIGH-RESOLUTION SOLID-STATE SI-29 NMR-SPECTROSCOPY OF SILICONE GELS USED TO FILL BREAST PROSTHESES

We have used Si-29 solid-state nuclear magnetic resonance (NMR) spectr oscopy to study the chemical structure of the silicone gels in virgin and explanted breast prostheses, Despite evidences of alteration in th e morphological appearance of the silicone gel inside the breast prost hesis, our results do not reveal changes in the chemical nature and st ructure of the silicone gels after implantation. In addition to the ma in Si-29 resonance peak at -22.26 ppm that corresponds to the resonanc e frequency of the D repeat unit of the polysiloxane chains, the high sensitivity of our NMR technique allows the detection of very low conc entrations of silicone compounds. Within our experimental detection li mit of 0.2%, no signal between -90 ppm and -150 ppm are observed, This indicates that no silica products are present inside the gel of the p rostheses, Furthermore, our Si-29 NMR spectra indicate differences in the chemical compositions of the silicone gels from different manufact urers.