Biofabrication of an ovine intervertebral disc model by combining a polycaprolactone frame with a bioprinted alginate hydrogel

This work reports the first biofabricated 3D ovine intervertebral disc (IVD) model combining melt electrowritten polycaprolactone (PCL) frames and bioprinted alginate-methacrylamide (AlgMA) hydrogels encapsulating nucleus pulposus (NP) and annulus fibrosus (AF) cells. The AlgMA hydrogel was formulated to approximate the native NP stiffness (~6 kPa), while the PCL frame guided AF cell alignment into lamellar organization. NP cells maintained a spherical morphology and high viability (~80 % over 28 days), whereas AF cells elongated and aligned along PCL fibers and expressed collagen types I and II. The composite construct successfully replicates the native anatomical architecture of ovine IVDs, providing a predictive platform for studying disc degeneration and therapeutic responses.