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

Abstract

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.

The role of oxidation and enzymatic hydrolysis on the in vivo degradation of trimethylene carbonate based photocrosslinkable elastomers

“…The oxidation studies in organic media were conducted according to the method established by Lee et al, which consisted of a mixture of KO 2 (0.01 M) and 18-crown-6 ether (0.002 M) in dried THF [13]. These conditions generate superoxide anion.…”

“…The role of oxidation in the degradation of poly(CL) was demonstrated by Lee and Chu, who showed that poly(CL) was susceptible to superoxide ion-induced degradation [13]. Thus, it was reasoned further that oxidation would play a role in the degradation of elastomers prepared from prepolymers of poly(TMCCL).…”

“…Others have also reported oxidative degradation of carbonate containing polymers in the presence of superoxide anion. For example, Lee et al treated commercially available Maxon sutures made of a block copolymer of 32.5 wt% of TMC and 67.5 wt% of glycolide with different concentration of KO 2 / 18-crown-6 ether/THF and found significant mass losses over a 24 h time period [13]. They concluded that the degradation observed had occurred mainly in the glycolide blocks since the carbonate group in the poly(TMC) is less reactive toward nucleophilic attack.…”

“…The literature indicates the susceptibility of poly(CL) segment of different copolymers to both oxidation and enzymatic hydrolysis [13,15,16]. For example, Gan et al exposed blends of poly(D,L-lactide) and poly (3-caprolactone) to Pseudomonas lipase and found that only CL regions were prone to enzymatic degradation [15].…”

Novel Biodegradable Polymer/Bioactive Glass Composites for Tissue Engineering Applications

“…[1±3] The most popular biodegradable polymers are polyesters such as polyglycolic acid (PGA) and polylactic acid (PLA). [1] They have found widespread use as biomedical materials for several applications such as surgical sutures, [4] bone fixation, [5] bone substitution, [6] as scaffolds for tissue engineering, [7±10] and for controlled drug release. [11] The mechanical properties and biological life-time of PGA and PLA co-polymers can be adjusted by variation of their degree of polymerization and crystallinity.…”