Preparation And Properties Of Poly (P-dioxanone)(PPDO) Barbed Sutures

Barbed sutures as a unique wound closure tool. Their advantages include the closure of wounds without any knots or the need for a third hand, it convenient for doctors and it has a shorter time. At present, the research of barbed suture seams are mainly in abroad, and this project study on the preparation and properties of the barbed sutures.First of all, according to the geometric structure of barbed sutures, we give the preliminary design of the control cut depth and cut angle control unit. At the same time, we add length scale on cut depth control parts to achieve control of cut distance. But due to the precision isn’t high enough we made improvements based on this design, and adjusted the size of the control members, so that operation is more convenient, and accuracy is also improved. But its efficiency is low. In order to have a more accurate precision, a higher efficiency and more convenient to operate, this project design a set of relatively complete barbed suture preparation plant.Different geometry of the barbed suture is designed according to the geometrical parameters, and prepared by the homemade mechanical cutting device. This project first discussed how the different geometric design of barbed effect on the biomechanical behavior of bar suture. Test the tensile strength of barbed sutures in different cut depth (0.17mm,0.20mm), the different cut angle (155°,165°) and different numbers of barbs (multiple barbs when shear distance of lmm). The results show that the strength of barbed suture reduced with cut depth deeper. However, the strength of barbed suture decrease with the cut angle increased. At the same time, Strength of0barbed sutures was intermediate between that of0and3-0nonbarbed sutures and was not significantly different from that of2-0nonbarbed suturesMeanwhile, in order in a relatively short period of time to study the degradation of performance of barbed suture it in vitro accelerated degradation test and conventional degradation experiments. Through different temperatures (50℃,60℃, 70℃) and different pH buffer solution (6.6,7.4,9.6) experimental conditions to accelerate the degradation. The experimental results shows the pH value is weak on the degradation, and under alkaline conditions it has slightly different. Temperature effect PPDO suture acceleration process is relatively clear, while deduced the relationship curve between temperature and degradation time, and this as a basis for subsequent experiments. Whether accelerated degradation test or routine experimentation, the surface of PPDO suture occurs hair liked degradation products in the early degradation, along with the degradation, the surface began to appear recess, until it fragmented into small pieces at the last. Strength is also reduced after the first increasing, because the water molecules are first into the amorphous region, so the crystallinity increased, strength increased. Subsequently, water molecules get into the crystalline region to destroy, so tensile strength reduced. On the other hand, the degradation of barbed suture is also similar to traditional sutures, but due to the degradation related to the specific surface area, therefore the strength loss rate of barbed suture is higher than traditional suture with the shape of bars getting gradually smaller.Finally, this project also discussed the pull-out force of barbed suture. As the degradation proceeds, anchoring effect of barbed suture on the tissue is weakening, because of the degradation process, the ability of tissue anchoring decrease with the shape of bars getting smaller. Also, do a comparative study on linear model and bending model. The bars easily closed by linear model, while bars can stand up by bending model, and thus it can hold greater range, the anchoring effect is better, the pull-out force is higher.