Performance of the polypropylene fiber tailstring on the copper 7 intrauterine device

Abstract

New and used polypropylene tailstrings from the Copper 7 (Cu-7) intrauterine device were examined by a combination of analytical techniques. Optical microscopy, scanning acoustic and electron microscopy, x-ray diffraction, energy dispersive x-ray analysis, and chemical etching were employed to elucidate both the surface and interior morphology of new Cu-7 tailstrings. Tailstrings removed from women following varying periods of use were investigated with optical microscopy, scanning and transmission electron microscopy. In addition, a subset of the used tailstrings were cultured to identify the types of microorganisms associated with them. Our findings show that unused Cu-7 tailstrings are in various stages of degradation owing to a combination of factors which include the high-draw ratio employed during manufacturing, the method of packaging, and the use of a particulate colourant. Furthermore, it is evident that used Cu-7 tailstrings undergo major deterioration while in situ because of the unfavorable interactions between the highly drawn polypropylene and the physiological environment. These results indicate that the polypropylene tailstrings as manufactured for use with the Cu-7 IUD fail to meet accepted design criteria for biomedical implants.

Surface roughness enhances upward migration of bacteria on polymer fibers above liquid cultures

“…As observed by optical microscope, the roughened fibers exhibited a significant increase in crevices and erupted fibrils similar to the surface features of used Cu-7 fibers reported by Warner et al [7]. Using a Wilhemy balance (see below), the contact angle of pure water was measured on roughened and as received fibers and found to be slightly greater than 90 deg.…”

“…Only straight portions of fibers without kinks were employed. In the as received condition, the fibers exhibited occasional longitudinal crevices and erupted fibrils as described previously by Warner et al [7] and Coughlin et al [6].…”

“…Except for a slight difference in diameter, these monofilament fibers are the same as fibers that have been used as tail strings in some IUCDS. They have been previously studied and physicochemically characterized by Warner et al [7], Coughlin et al [6], Mahmoud et al [5], Roylance et al [8]. They are the same fibers used by Magnotta et al [ 1 1 ].…”

“…151 and Coughlin et al [6], although the former authors pointed out that microscopically thin films of water may be present between the fibers and the adjacent agar and thus play a role in the observed migration. It has been argued [6,7] that the rough surfaces of the Cu-7 IUCD may abet the attachment and migration of bacteria. These authors observed that the surfaces of such polypropylene retrieval strings have multiple longitudinal channels or grooves formed by the spontaneous generation of smaller fibrils that erupt from the surfaces of the fibers.…”