Abstract: Abstract: Objective To investigate oriented polycaprolactone (PCL) microfiber scaffold for intervertebral disc (IVD) tissue engineering and verify the feasibility as a potential candidate for IVD tissue engineering. Methods A biomimetic circumferentially oriented microfiber scaffold was prepared by wet spinning method using PCL solution. The scaffold was investigated by stereomicroscope. The scanning electron microscopy (SEM) and micro-CT were used to determine the microstructure, porosity and fiber diameter of the scaffolds. The rabbit annulus fibrosus (AF) cells were isolated from IVD and seeded into the microfiber scaffold. The cell-scaffold complex was cultured for 14 days in vitro. The biocompatibility of the scaffold was evaluated by SEM and Live/dead staining. The cell attachment and infiltration were evaluated by phalloidin staining and DiI fluorescence labeling. The histology analyses of the cell-scaffold were examined by H&E staining, Safranin O staining, and type Ⅰ immunohistochemistry and immunofluorescence staining. Results The stereomicroscope images showed that the AF scaffold presented a ring structure similar to the native AF tissue. SEM and micro-CT revealed that the AF scaffold was 3D circumferentially oriented fiber structure without adhesion. The scaffold had a porosity of 69.33%± 6.67%, and the fiber diameter was (16.13±2.77) μm. SEM and phalloidin staining revealed that the AF cells spread along the fiber direction. The DiI-labeled images revealed that the AF cells grew into the inside of the scaffold after 14 days of culture. Histological staining showed that the AF cells grew inside the scaffold and spread along the microfiber direction and secreted AF-related extracellular matrix, which also oriented along the microfiber direction. Conclusion The biomimetic circumferential oriented PCL microfiber scaffold has high porosity and good biocompatibility, and could guide oriented growth of AF cells and orient deposition of AF-related ECMs. They are ideal scaffolds for the application of regeneration of IVD.

Key words: tissue engineering, intervertebral disk, scaffolds, annulus ?brosus, polycaprolactone