The role of superoxide ions in the degradation of synthetic absorbable sutures.

The objective of this study was to examine the effect of superoxide ion-induced degradation on synthetic absorbable biomaterials. Synthetic absorbable sutures were used as the model compounds. Inflammatory cells, particularly leukocytes and macrophages, are able to produce highly reactive oxygen species, such as superoxide (. O(2)(-)), during inflammatory reactions to foreign materials. Superoxide ions may act as oxygen nucleophile agents to attack biomaterials. In this study, the changes in tensile breaking force, thermal properties, and the surface morphology of five commercial (2/0 in size) synthetic absorbable sutures (Dexon, Vicryl, PDS II, Maxon, and Monocryl) as a function of superoxide ion concentration at 25 degrees C for 24 h were studied. Among the five absorbable sutures and over the concentration range of this study, the monofilament Monocryl suture was the most sensitive toward superoxide ion-induced degradation, followed by Maxon, Vicryl, Dexon, and PDS II sutures. The amount of tensile breaking force loss over a 24 h period ranged from as low as 3% to as high as 80%, depending on the type of absorbable sutures, the reaction time, and the superoxide ion concentration. All five absorbable sutures showed significant reductions in both the T(m) and T(g). Unlike the surface morphological changes of absorbable sutures in conventional buffer solutions, the effect of superoxide ion-induced degradation on the surface morphologies of these five absorbable sutures was unique, particularly the moon-crater-shaped impressions of various sizes and depths found in Monocryl and Maxon sutures, which defied the anisotropic characteristics of fibers. Copyright 2000 John Wiley & Sons, Inc.