A novel bilayer coating on 3D printed polycaprolactone /eggshell scaffolds for tissue engineering applications

Abstract In recent years, numerous studies have investigated the use of polycaprolactone and eggshells in preparing bone tissue engineering scaffolds, owing to their outstanding load-bearing capacity and bone-regenerative activity. Notwithstanding the great potential of these materials, their hydrophobicity remains a challenge. To enhance the hydrophilicity of scaffolds made from these materials, we developed novel composite scaffolds of polycaprolactone and eggshell powder and coated them using various techniques. Three-dimensional scaffolds of polycaprolactone and eggshell with different ratios (i.e., 3%, 5%, 7% wt) were prepared. The printed scaffolds were coated with egg white protein and chitosan by submerging them. After characterizing the coated scaffolds, selected samples received a second coating layer via plasma treatment and electrospinning of a gelatin-hydroxyapatite solution. These surface modifications significantly reduced the contact angle and increased scaffold hydrophilicity. Additionally, MTT assays, bioactivity, and mechanical tests of the developed composite scaffold indicated excellent Cytocompatibility, high in vitro bioactivity, and favorable mechanical characteristics, attributed to the presence of gelatin, chitosan, hydroxyapatite, and polycaprolactone in its structure. Collectively, the developed scaffolds demonstrate osteoconductive, apatite-inducing, and pro-proliferative properties, positioning them as promising platforms for bone tissue engineering applications.