Macro-alignment of electrospun fibers for vascular tissue engineering.

Design of polymeric scaffolds with specific physical and biological properties is a key objective of tissue engineering research. Electrospinning generates loosely connected 3D porous mats simulating extra cellular matrix structure and therefore makes itself an excellent candidate for application in tissue engineering. Besides a high voltage generator and syringe pump, our electrospinning system was improved to add a programmable central controller which monitors system operation. The nozzles connected with syringe pump via silicon rubber tubing can move linearly with a step size of 0.1 microm or above while the mandrel collector rotates at a speed from 400 to 3000 revolutions per minute (rpm). Using this system, porous fiber sheets with fiber diameters ranging from 100 nm to several micrometers or meshes of macroscopically aligned fibers with diameter of approximately 10 microm have been fabricated under proper processing conditions. After biocompatible fibrin coating, oriented polycaprolactone (PCL) fibers were found to enhance the shifting of human umbilical artery smooth muscle cells from synthetic to contractile phenotype, and to maintain biological function of human umbilical vein endothelial cells. We believe that our electrospinning system will facilitate scaffold fabrication for vessel tissue engineering.