Design and Fabrication Method of Bi-Layered Fibrous Scaffold for Cartilage Regeneration

Abstract

An advanced therapy construct for regeneration of articular cartilage is reported which was fabricated by cryo-electrospinning as 3D multi-layered poly[e]caprolactone matrix harbouring chondrogenic growth factor TGFβ-3. The layers have been designed to favour the cartilage regeneration (chondral layer) and bone tissue formation (subchondral layer) by additives of regenerated cellulose and hydroxyapatite, respectively. The overall porosity of the chondral layer was 90.7% and the subchondral layer – 94.4% with a pore diameter ranges of 50–300 μm and 75–400 μm respectively but maintaining a low fibre diameter of 9.3 ± 4.1 µm and 9.1 ± 2.1 µm. The hydrophilicity was enhanced and functional groups essential for growth factor incorporation were introduced by surface ozone treatment. The scaffold was characterized by SEM, µCT, FTIR, WCA, XRD, TGA, and DSC techniques. The processing of scaffold by chemical modifications resulted in the increase of biodegradability of the scaffold, as indicated by the decrease of the crystallinity, thermal stability, melting peak, and hydrophobicity, but maintaining its sufficient mechanical properties (Young’s modulus equalled to 1.8 ± 0.1 MPa for chondral layer and 1.1 ± 0.2 MPa for subchondral). The release kinetics of TGFβ-3 followed the Korsmeyer–Peppas model, reaching 39.3% after 72 hours, and the estimated 50% release after 155 hours.