Textile-based Ca-alginate/Polyacrylamide Hydrogel Small-diameter Vascular Graft Materials

For patients with arterial disease,implantation of vascular prostheses is necessary.However,small diameter artificial blood vessels are still not satisfactory clinically.My research group have carried out some relevant research work in hydrogel small-diameter vascular grafts materials,such as gelatin hydrogel small-diameter vascular graft materials,sodium alginate/polyacrylamide hydrogel vascular graft materials and so on.There are still some problems of hydrogel vascular graft prototype,such as poor mechanical properties and high swelling ratios.It could not meet the need of implantation.Therefore,in this study,a desired hydrogel vascular graft with higher mechanical properties and lower swelling ratios was obtained.The main research contents of this study as follow: 1.Controlling the reaction speed and structural homogeneity of hydrogel.2.Choosing the optimum process to obtain the hydrogel with higher mechanical property and lower swelling ratio.3.Preparing the hydrogel tube and textilebased composite hydrogel tube with higher mechanical property and lower swelling ratio.4.Evaluating the biocompatibility of hydrogel vascular graft materials.Results and main conclusions of this study as follow:1.CA/PAAm hydrogels with homogeneous structure and stable properties was prepared by the sodium alginate(SA)and acrylamide(AAm).In addition,it have higher mechanical properties and lower swelling ratios(100%).2.A tubular mold was specially designed for the preparation of a tubular hydrogel.In order to obtain the composite hydrogel tube,a braided tube was fabricated to combine with the hydrogel tube.The two kind of hydrogel vascular grafts were all transparent and smooth.The results showed that the compliances of two kinds of hydrogel tubes were good.Meanwhile,the swelling ratio could be stabilized at 100%.3.Through the compare with hydrogel tube,we concluded that the composite hydrogel tube reinforced by braided tube of PET had higher mechanical property.When the elongation ratio of the composite hydrogel tube was 50%,it showed a solid integration of the hydrogel tube and the braided tube during elongation,and the tensile strength(192.65±6.91 k Pa)was higher than porcine carotid artery;the suture retention strength(8.35±0.54 N)was higher than canine femoral artery;the radial dynamic compliance were higher than a commercial e-PTFE graft under three pressure spans,respectively.Meanwhile,in the pressure range(0 k Pa-16 k Pa),the fluid can’t spill out from the hydrogel tube after puncturing.4.The results showed that the best sterilization method was autoclaving.The vitro cytotoxicity test result showed that the relative growth rates were more than 80 %,so the toxic level of the hydrogel material was 1 Grade.The vitro hemolysis test result showed that the hemolysis ratio was(0.86 ± 0.23)%.Therefore,the biocompatibility of the hydrogel material could meet the need of implantation.In conclusion,the textile-based CA/PAAm hydrogel composite tube has the potential to be the small-diameter vascular graft material for implanting.The material has higher mechanical property,lower swelling ratio,and good biocompatibility.