Studies Of Implantation PP Monofilaments And Meshes For Soft Repair Tissue

Hernia and pelvic floor dysfunction are common diseases occurring frequently in elder men andwomen respectively, and the main treatment is implanting mesh to replace the damaged and weakfascia tissue. Thus, the soft-tissue implanted meshes are required to possess good bio-compatibility and appropriate mechanical properties. Most meshes used in hernia repair and pelvicfloor repair are made of polypropylene. At present, the domestic demand mainly relies on import,thus the research on PP meshes is of great significance.In this study, three kinds of PP/pearl powder composite monofilaments were prepared bymelting spinning using plant equipment, the content of pearl powder was respectively1wt%,1.5wt%,2wt%, and the diameter was respectively0.1mm,0.08mm,0.1mm. Then PP/pearlpowder composite monofilaments were weaved into meshes in the way of wrap knitting. Afterbeen weaved, the meshes needed going through heat-setting process for stabilize shape. The mainwork and results are as follows:1.The processing parameters of melt spinning were determined, and PP/pearl powder compositemonofilaments were prepared. The properties of PP/pearl powder composite monofilaments wereinvestigated by Scanning Electron Microscopy(SEM), Differential Scanning Calorimetry (DSC),Thermo-gravimetric Analysis(TGA), Sonic velocity orientation test and mechanical test. Thecytotoxicity was tested by MTT assay on mouse fibroblast cell line(L929). Results showed thatpearl powder was dispersed on the surface of monofilaments; the crystallization temperature ofPP/pearl powder was around115℃, and the melting temperature is around165℃; The content ofpearl powder caused no obvious impact on sonic velocity and mechanical properties, and theelongation breaking strengths of three kinds of monofilaments were all over5.0cN/dtex, meetingthe require of medical Polypropylene monofilaments. The MTT assay showed three kinds ofPP/pearl powder were of good bio-compatibility.2.The meshes were made of three kinds of PP/pearl powder and were weaved with warpknitting technology. Then taking temperature and time as two variable factors in heat settingtreatment, we discussed their individual impact on meshes. The mechanical properties such asbending stiffness, elongation breaking strength, bursting strength and suture pull-off strength of meshes after heat-setting in different condition were measured. The results showed that thetemperature caused definite effect on mechanical properties: the mechanical strength decreased astemperature increasing; while the factor of time didn‘t show obvious effect on mechanical strength.The optimal heat-setting temperature and time were120℃,10min. All kinds of meshes were ofhigh porosity, low areal density and small thickness, as well as good mechanical properties.3.The influence of heat treat on bio-compatibility of PLA was studied by MTT assay, and thetemperature of heat treatment was180℃,210℃,230℃, respectively.The result showed the bio-compatibility of PLA could get improved after heat treatment. At the same time, we took researchon heat treatment‘s influence on bio-compatibility of pearl powder. The heat treatmenttemperature of pearl powder was respectively230℃and270℃, then we prepared pearlpowder/PLA blend membrane with different contents of pearl powder. The MTT result showedthat the bio-compatibility of pearl powder increased while temperature increased. The bio-compatibility of PP prepared on four different kinds of catalysts showed the four kinds of catalystsweren‘t suitable for preparing medical using PP.