Research On The Structure And Property Of The Scaffold For Tendon Tissue Engineering

Tendon injury is very common in the physically active population. The tissue engineering technique provides an ideal method and keeps the promise for tendon repair. The tendon can avoid the resource restrictions, immune reactions, and immuse response problem. Besides the new organization has viability and function, and can reach to the normal tendon shape.The performance of scaffold includes biocompatibility, mechanical property, structural stability and the porosity size. Present studies of tissue engineering scaffolds also have good biocompatibility. However these scaffolds cannot satisfy the requirements at the same time:stable structure, larger porosity, and good mechanical properties.This paper select pologiycolic acid (PGA) and polylactic acid (PLA) multifilament, they both have good biocompatibility. Utilizing PGA and PLA multifilament to braid combined yarns, and the plain stitch and tricot stitch are manufactured through weft and warp knitting technology while the rhombic and rectangular netty structure scaffold reinforcements are hand-knitted. We compared the extensibility, porosity, pore size, and mechanical properties of the four kinds of scaffold reinforcements. The studies have shown that rhombic netty structure scaffold reinforcement has stable structure and small extension, but its mechanical property is low. The plain stitch netty structure scaffold reinforcement has the smallest porosity and pore size, but its mechanical property is the best.This paper studied the basic properties, performance during degradation in vitro of PGA and PLA multifilament, besides researched the performance of braided yarns and their scaffolds with different PGA/PLA during degradation process. The results showed that the PGA multifilament degraded faster than PLA multifilament, PGA’s strength can’t get two weeks later, and it lost almost all the mass after5-week degradation. But the performance of PLA multifilament had little change. As the PGA increased among PGA/PLA braided yarns, the degradation speed of braided yarns and scaffolds increased. The fineness of braided yarns had no effect to braided yarns’ degradation, but had a little effect to scaffolds.This paper made plain stitch, tricot stitch, rhombic and rectangular netty structure scaffold reinforcements, and researched their degradation performances. The results showed that during the degradation process, in the first3weeks the tensile strength reduced sharply and the thickness increased slightly; between the4th week and6th week the mass loss increased tremendously and the thickness reduced rapidly; the porosity experienced a decreasing trend and then an increasing trend during the degradation process, and it reached its minimum value between the3rd and4th week. The caliber of two hand-knitted scaffold reinforcements had no obvious change during degradation, but the caliber of the plain stitch decreased gradually in the first3weeks and then bounced back gradually.The influence of heat setting process (temperature, time, heat setting method) on the mechanical property of polyglycolic acid (PGA) fiber and braided yarns were investigated. Both PGA scaffolds before and after heat setting were placed in phosphate buffer solution (pH value is7.4) at37℃for four weeks degradation. The experimental results show that both the heat setting temperature and heat setting time have effect on mechanical property of the PGA fiber and braided yarns. The mechanical property of PGA fiber and braided yarns were better by stretch heat setting method at a temperature within the range of40to60℃and time from3to5min. The mechanical property of scaffold after heat setting is better than without heat setting in the degradation process.