The effect of sterilization methods on electronspun poly(lactide-co-glycolide) and subsequent adhesion efficiency of mesenchymal stem cells.

The sterilization of scaffolds is an essential step for tissue engineering in vitro and, mainly, clinical biomaterial use. However, this process can cause changes in the structure and surface of the scaffolds. Therefore, the objective of this study was to investigate the effect of sterilization by ethanol, ultraviolet radiation (UVR) or antimicrobial solution (AMS) on poly(lactide-co-glycolide) (PLGA) scaffolds produced by the electrospinning technique. The properties of nanofibers and the cellular adhesion of mesenchymal stem cells to the scaffolds were analyzed after the treatments. All methods generated sterile scaffolds but showed some kind of damage to the scaffolds. Ethanol and AMS caused changes in the morphology and scaffold dimensions, which were not observed when using the UVR method. However, UVR caused a greater reduction in polymeric molecular weight, which increased proportionally with exposure time of treatment. Nanofibers sterilized with AMS for 1 h and 2 h showed greater cellular adhesion than the other methods, demonstrating their potential as a method for sterilizing PLGA nanofibers.

Irradiated polyglactin 910 (Vicryl Rapide) for placement of full-thickness skin grafts.

BACKGROUND: The "unsuture" technique originally reported with the use of fast-absorbing gut for the placement of full-thickness skin grafts has provided years of successful full-thickness graft placement without the need for suture removal. OBJECTIVE: The objective was to explore another option for successful graft placement and survival using irradiated polyglactin 910 (Vicryl Rapide, Ethicon Inc, Somerville, NJ, USA), with its longer tensile strength of 7 to 10 days. METHODS: Irradiated polyglactin 910 was used to suture the edges and place basting sutures in full-thickness skin grafts. RESULTS: In our experience, we have found that the use of irradiated polyglactin 910 for the placement of full-thickness skin grafts provides an alternative to the "unsuture" technique with fast-absorbing gut. It provides excellent graft survival, easy workability, low inflammation, and good long-term cosmesis, without the need for suture removal. CONCLUSION: Irradiated polyglactin 910 provides another option for the placement of full-thickness skin grafts without the need for suture removal.

An EPR and ENDOR study of gamma- and beta-radiation sterilization in poly (lactide-co-glycolide) polymers and microspheres.

EPR/ENDOR spectroscopy was used to characterise the free radicals generated in a series of PLGA raw polymers and microspheres (with lactide:glycolide compositions of (75:25), (65:35) and (50:50)) after exposure to gamma (gamma-) and electron beam (beta-) irradiation at room temperature. Both sets of irradiated samples produced analogous EPR spectra, indicating that the type and distribution of free radicals generated by gamma-irradiation are similar to those generated by beta-irradiation. The radicals were identified by EPR simulations as the chain scission species -(CHO-(approximately 27% abundance),-C(CH(3))O- ( approximately 23% abundance) and the terminal-C(CH(3))-OR fragment (approximately 50% abundance), and these assignments were supported by the ENDOR analysis. The latter two radical species were demonstrated to originate from the lactide component of the PLGA polymer. Overall systematically higher radical concentrations were found as the lactide content of the PLGA raw polymer and microspheres increases (ie., 75:25 > 65:35 > 50:50) for both gamma- and beta-irradiation. However, while the relative concentrations of free radicals was similar in the raw polymer samples after exposure to gamma- or beta-irradiation, a substantial difference was found for the microsphere samples; an approximate doubling of the radical content was found in the gamma-irradiated PLGA microspheres compared to the identical beta-irradiated microspheres.

Poly(L-lactide/glycolide) suture: the effect of acute radiation.

UNLABELLED: The physical properties of Poly(L-lactide/glycolide) indicate that the suture retains approximately 80% of its original strength at 3 months and 60% of its original strength at 6 months. This new long-term synthetic absorbable suture offers postoperative fascial strength for an extended period when compared to other available absorbables. Importantly, many women with gynecologic cancer will undergo radiation therapy during this interval. This report is intended to evaluate the effects of ionizing radiation on this suture. METHODS: One lot (op strands) of size 1 PLG suture was used. Ten (10) strands were used for baseline study of out of package tensile strength. Eighty (80) strands were placed in a buffer solution (pH approximately 9.0) and incubated in an in vitro water bath approximately 48 h at 55 degrees C to simulate 4 weeks in vitro residence time. Following this in vitro hydrolysis 20 strands were tested. Sixty strands were placed beneath a piece of fresh full thickness porcine skin and subcutaneous tissue and exposed to 3, 30, and 70 Gy. All samples were evaluated for breaking strength and elongation-at-break using an Instron tensiometer. RESULTS: Analysis of variance performed at the different exposure level revealed no significant effect on tensile properties (p>0.1). CONCLUSION: The tensile properties of PLG suture are not adversely affected by ionizing radiation. This long-term absorbable suture is an alternative for fascial closure when extended periods of support are necessary in patients destined to receive therapeutic ionizing radiation.

Rate of loss of irradiated polyglactin 910 (Vicryl Rapide) from the mouth: a prospective study.

We aimed to find out how long irradiated polyglactin 910 (Vicryl Rapide) remained in the oral tissues and to investigate the effect of chlorhexidine mouthwash on absorption time and bacterial growth on sutures. Twenty-one volunteers each had two Vicryl Rapide sutures placed intraorally under local anaesthesia. Ten of these subjects used chlorhexidine mouthwash twice daily. After 7 days, one suture was removed to be cultured for aerobic and anaerobic bacteria. The other was monitored for time from insertion to loss. The median survival value was 3 days (range 1-13). The median number of days to suture loss was less in the chlorhexidine group (3, range 1-11) than in the control group (4, range 1-13) but this was not significant. There were no significant differences in aerobic and anaerobic counts between the two groups. Vicryl Rapide may be useful for intraoral use.

Outcomes of irradiated polyglactin 910 Vicryl Rapide fast-absorbing suture in oral and scalp wounds.

BACKGROUND: This study evaluated the outcome of wounds closed with irradiated polyglactin 910 (IRPG) Vicryl Rapide (Ethicon, Somerville, N.J.). METHOD: Seventy-one patients with 80 oral wounds and 42 patients with 42 scalp wounds closed with IRPG were evaluated on the day of surgery, then one, seven, 14, 28 and 90 days following surgery. The incidence of inflammation, suppuration and hypertrophic scarring was recorded, along with the timing of spontaneous suture disappearance. This suture material was compared with polytetrafluoroethylene (PTFE) sutures used in dental implant patients, traditional polyglycolic acid (PGLA) sutures used in osteotomy patients and skin staples used in patients with scalp wounds. RESULTS: In the group with intraoral wounds, there were two cases of suppuration with no inflammatory reactions or hypertrophic scarring when IRPG sutures were used, compared to three cases of suppuration with the traditional PGLA sutures. In the group with scalp wounds, there was no suppuration or hypertrophic scarring with IRPG sutures and one inflammatory reaction with skin staples. IRPG sutures never required removal, while all staples, PGLA and PTFE sutures eventually required separate removal. CONCLUSION: Irradiated polyglactin 910 Vicryl Rapide is a useful suture material with both intra- and extraoral applications in the pediatric and adult populations.