Fabrication And Properties Of PCL Membrane Surface Modified By Coaxial Electrospraying For Vascular Graft Application

In the reconstruction of small diameter vascular (<6mm), the vascular graftfrequently leads to the coagulation, thrombosis, eventually the failure of clinicaltransplantation after implanted. The modification of materials to improve theanti-coagulation and the long-term patency rate of vascular graft becomes animportant topic of research.Recent years, biodegradable polymers have been paid much attention in the fieldof biomedical materials, such as PCL, PLA, PGA, etc. Poly (ε-caprolactone)(PCL)possesses excellent biocompatibility, biodegradability. Meanwhile the degradationproducts are not toxic in vivo, so it has been approved by FDA. In addition, it hasgood flexibility and machinability. However, due to the hydrophobicity and highcrystallinity, PCL is limited to the application. Through the modification for PCL, itshydrophilicity, biocompatibility, especially the blood compatibility could be improved.Different methods have been widely applied to the modification of PCL so as toreduce the plasma protein adsorption and avoid thrombosis, thus improving thelong-term patency rate of vascular graft.Based on the method of drug-loaded coating, using Coaxial ElectrosprayingTechnology to fabricate of drug-loaded core-shell microspheres. Anticoagulant drug,such as Heparin, is encapsulated in biodegradable polymer, and then the core-shellmicrospheres are sprayed onto the PCL porous membrane. Because of the samesolvent, the core-shell microspheres are successfully loaded on the surface ofmembrane. With the degradation of polymer, the drug can be released in control.Firstly, this Study focuses on the fabrication of PEG-PCL microspheres byElectrospraying, the particle size distribution is assessed by controlling the solutionconcentration and other parameters. Secondly, discuss the fabrication ofPEG-PCL/heparin microspheres. At last, spray the core-shell microspheres onto theprepared PCL porous membrane.Through adjusting the parameters of Electrospraying, the core-shellmicrospheres are fabricated with well structure. The SEM/TEM, FTIR and XRD areused to estimate the morphology and structural characterization of core-shellmicrospheres.Evaluate the hydrophilic and mechanical properties of PCL porous membrane byCalculation of Porosity, Contact Angle Testing and Stretch Testing. Finally, theperformance of PCL porous membrane are tested before and after the modification.The results show that the heparin is released in control with the degradation of polymer, therefore it can improve the anticoagulation of PCL porous membrane forsmall diameter vascular graft application.