Preparation And Evaluation Of Bacterial Cellulose-based Small-diameter Vascular Grafts

Objective: The bacterial cellulose(BC)membrane was prepared and dehydrated.Its physical properties were evaluated.Then the BC-based artificial small blood vessel was produced by culturing Gluconacetobacterxylinus in a 2 mm medical silicone rubber mold.We estimated the feasibility of BC vessel through the carotid artery replacement model in rabbits.At the same time,we use HUVECs as seed cells to study the antithrombotic ability of REDV-modified BC in vitro.Methods: The bacterial suspension was prepared by culturing Gluconacetobacter xylinus in HS medium.Small-diameter artificial blood vessels was prepared by oxy gen infiltration single tube method in 2 mm medical silicone rubber mold.SEM an d tensile tests were used to assess the physical properties of BC before and after d e-hydration.Meanwhile,differential scanning calorimetry(DSC)was used to test the thermodynamic properties.Then,we carboxylated the BC material with 2,2,6,6-tetra methylpiperidine oxide free radical(TEMPO).The BC material was further treated by the chemical method of EDC/NHS to active carboxyl group,finally the REDV peptide was fixed onto BC surface.The HUVECs were cultured on BC membrane for 5-7 d.Fluorescence staining method was used to observe and compare the cell adhesion between BC and REDV modified BC.Results: BC-based small-diameter artificial blood vessels can be prepared by culturing Gluconacetobacterxylinus with 2 mm medical silicone rubber mold.The diameter is the same as the mold diameter,matched with the diameter of rabbit carotid artery.The surface of BC after dehydration was observed by SEM,its nanofibers structure was complete,which was clearer than that before dehydration.Tensile test showed that the breaking tensile stress of BC was significantly higher than that before dehydration.DSC shows that dehydration process did no effect to the thermodynamic properties of BC.The carotid artery replacements in rabbits were successfully established through vascular cuff anastomosis.The blood flew can be seen in the artificial blood vessel without any leakageafter the transplantation.The performance of the implanted BC vessels in the rabbit carotid artery for 30 d was verified by HE staining,results show significant blockage in both samples.The HUVECs were intact and well grown on the BC surface,and the adherent rate of cells is significantly higher on the modified BC surface than the unmodified BC surface.Conclusion: The BC artificial blood vessel with uniform diameter can be made by medical silicone rubber mold,dehydration can effectively improve the functions of bacterial cellulose.We successfully established a rabbit carotid artery replacement model via vascular cuff anastomosis,which demonstrates the feasibility of BC artificial blood vessel for vascular anastomosis.The modified BC surface with REDV significant increase the adhesion of endothelial cells.