PET Fiber Artificial Ligament Preparation, Chitosan Grafting Method And The Surface Structure Performance Analysis

BackgroundAs a serious common damage, Ligament injury （Ligament Injury, LI） seriouslyaffect the quality of the patient’s life, and the incidence is rising, unpropertreatment can lead to instability and joint chronic damage, and other seriousconsequences. According to the statistics, just for knee ACL injuries, there aremore than400000cases in the United States a year. Autologous transplantationis currently accepted the gold standard of ligament reconstruction. However,because of the damage of autologous for district organization there existedcorresponding more complications. Since the1960s, the clinical application ofartificial ligament, for the treatment of ligament damage provides a newsolution.After the1980s, because all kinds of synthetic materials, the emergence of many different types of artificial ligaments are widely used in clinical, and popular atthat time, but then due to serious complications （such as an acute synovialinflammation, artificial ligament, etc）, phased out. Until the1980s, along withthe further development of learning materials, artificial ligament back into theclinical. LARS ligament is the most widely used at present, the most outstandingrepresentative. And autologous transplantation, allograft comparison, artificialligament has its advantage:（1） no damage to the other parts of their ownorganization, not corresponding sequela;（2） the operation simple, smalltrauma and easy application;（3） no need brake, postoperative can obtainsufficient stability, postoperative recover quickly;（4） does not exist the spreadof the disease risk;（5） source materials widely.Polyethylene glycol terephthalate （PET） with excellent mechanical properties（biology inert, flexibility, and creep resistance degeneration and fatigueresistance, etc）, because itself has certain water affinity groups （such ashydroxyl and carboxyl）, make it has certain biological compatibility. Butbecause of terephthalic acid glycol esters together the molecular structure ofsymmetry, high crystallinity, structure and not high polar groups, hydrophilic ispoorer, biological compatibility is not satisfactory, the imported products highprice is to let people unbearable heavy burden.The surface modification methods of improving the biocompatibility of thematerial are the current research hot spot. Meanwhile, after knitting formed afterthe host cell guide （such as Bone Marrow Mesenchymal Stem Cells, BMMSCs）adhesion, proliferation and differentiation, make the material in the body formlong-term biological connection is at present to be desired. At present, there isno with independent intellectual property rights of the artificial ligamentproducts. A has better biocompatibility of their own ligament product development, for great clinical significance, social value and economic value.Objectives1. To Explore PET fiber artificial ligament woven molding process andmethod.2. To Explore PET fiber material surface modification method.3. Multi kinds of methods to analysis of surface modification methods andcharacterization of graft chitosan bioactive molecules effect.Methods1. PET fiber artificial ligament woven molding: independent improvementTricot type double comb the weft knitting lining of knitting machine, reduce thewidth to48inches, and on board the secret8¹0/cm, the horizontal dense3⁵/cm. Comb section1using universal fracture strength for2.0cN/dtex,10%ofthe polyester fiber elastic variables, comb section2respectively by means offour different specifications （1100D,1670D,3300D,4400D） high purity ofthe PET fiber materials, machine speed3000r/min, knitting. Under the scanningelectron microscope （SEM） observation，measuring the pore size.2. Different modification methods of PET fibers material surface of thehydrophilic influence: take4400D high strength PET fiber woven materials,100℃water bath after30minutes after the low temperature cooling, cut for5cm2size, packet processing: Blank control group （PET）, hydrolyzedmodification group （PET-OH）, chemical modification group （PET-C）, radiationmodification group （PET-UA）. Microscope to take measure method to detectmaterials and modified water, glycol contact Angle.3. Radiation graft polymerization of chitosan and its surface characteristicsanalysis: take radiation modification group （PET-UA） woven materials,4℃ constant temperature grafted chitosan. Deionized water and water from ethanolrepeated cleaning, vacuum drying24h. Under the scanning electron microscope（SEM） observe fiber modified the diameter of the change, infrared spectroscopytesting surface groups; X-ray photoelectron spectroscopy analysis materialsurface elements changes. Thermo-gravimetric analysis detection rate of graft;Results1. Knit material characteristics and pore size:1100D for fiber bundles oflow strength, the number of single fiber less, although after the lower speedweaving machine methods of forming, but fabric structure extremely unstable,pore size large difference, cannot use.1670D,3300D,4400D organizationcontent, structure is stable, although the pore size is irregular, but the averagesize of pore relatively homogeneous, among them, the4400D group bundlespore diameter of128.2029.33μ m, between fiber pore diameter of24.504.71μ m; The hot shrink after processing bundles pore diameter of115.4524.62μm, between fiber pore diameter of23.20±3.58microns. Although a similarimported products is still too large, but not influence modified graftedexperiment, and can satisfy the subsequent cytology basic needs.2. Different modification methods of PET fibers material surface of thehydrophilic influence: ftir test material surface changes groups, the resultsshowed that: did not handle the ir spectra of the PET fabric,720cm-1placenearby for O-C-O face the bending vibration and the characteristics of longcarbon chain absorption peaks;875cm-1for the face of benzene in CH bendingvibration peak;1410cm-1place for bending in-plane vibration of benzene CHpeak;1240cm-1place for PET structure of vibration absorption ester-andtelescopic peak;1710cm-1place for aromatic ring C=C vibration and ester inkey carbonyl resonance absorption peaks. Modified group and hydrolysis blank compared to the1700cm-1place （C=O key） and3200³500cm-1place（O-H key） absorption peak has increased, confirmed that the increase of thematerial surface vc-vac, carboxyl change. Chemical modification group andblank compared to the1700cm-1place （C=O key） and3200³500cm-1place （O-H key） absorption peak increased; Hydrolysis group compared with themodification,3200³500cm-1place （O-H key） absorption peak no obviousdifference, and1700cm-1place （C=O key） absorb the peak of the increase ismore significant, confirmed that success in the material grafted acrylic surface,the introduction of a lot of carboxyl. Radiation polymerization modificationgroup and blank compared to the1700cm-1place （C=O key） and3200³500cm-1place （O-H key） absorption peak significantly increased; Group comparedwith chemical modification, C=O key absorb higher peak. Microscope to takemeasure method to detect materials and modified water the contact Angle, andthe results showed that the water contact Angle blank control group was85.37±1.53, hydrolysis modified water contact Angle of70.05±1.58, before and aftercomparison analysis statistically significant （p <0.05, n=6）; After chemicalmodification water contact Angle of53.62±1.37, compared before and after astatistically significant difference （p <0.01, n=6）; Radiation polymerizationmodified water contact Angle of48.00±0.95, compared before and after astatistically significant difference （p <0.01, n=6）; Hydrolysis modification,chemical modification water contact Angle between groups of comparativeanalysis with statistical difference （p <0.05, n=6）; Hydrolysis modification,radiation polymerization modified water contact Angle has comparative analysisstatistical differences （p <0.05, n=6）; Chemical modification, radiationpolymerization modified water contact Angle are statistically significantcomparative analysis （p <0.05, n=6）. 3. Radiation graft polymerization of chitosan and its surface characteristicsanalysis: characteristics analysis: TGA analysis shows that the surface of thePET coated quantity is9.66wt%. ESEM observation shows: chitosan grafting,PET diameter of fiber increased to31.546±0.897um. Before modification andmodified the comparative analysis, fiber diameter increased significantly, thegrafted thickness of2.250±0.335um, FTIR analysis shows that in3400cm^-1the emergence of a hydrogen bond for associating-OH and NH unit telescopicvibration absorption peaks and obvious overlapping increase wide strongabsorption peaks that indicates chitosan long chain molecules grafted in PETsurface.1670cm^-1in the peak of around there was the key characteristics forabsorption peaks. In addition, in2920cm^-1and2880cm^-1place enhancedabsorption peaks, attributed to chitosan in C-H two telescopic vibrationabsorption peaks. XPS analysis shows that chitosan after modification, PETsurface C1s and O1s peak reduced significantly, and with the corresponding isthe emergence of N1s peak.Conclusion1. Using the satin weave method can provide stability of the PET fiberfabric structure, and can according to need to complete the preparation ofcomplex structure. By adjusting the fiber materials specifications and loomstructure, can be suitable for the host cell adsorption, migration of the pore size,but at present the pore is similar imported products too large, and not enoughuniformity, weaving process should be further improved.2. Three different modification methods all can improve hydrophile of PETmaterials, and the result was statistically significant, and reported consistentbefore conclusion. Radiation polymerization modification, the effect is better than the other two modified method, may and reaction area greater efficiency isrelated to such factors. This method, fast and efficient, easy to operate.3. Via the amidation reaction, successful in introducing the carboxyl groupPET fiber material surface grafted chitosan molecules.4. Through the surface modification treatment and graft chitosan molecules,can significantly improve the PET hydrophilic materials, for further cytologyprovided the basis of experiments.