Dual porous architecture of poly(ε-caprolactone) scaffold loaded with nanostructured carbonated hydroxyapatite and cellulose nanofibril enhances in vitro biocompatibility

The development of biocompatible scaffolds that can mimic the hierarchical structure of bone and are biodegradable in harmony with the native growth cycle of new bone remains a challenge in bone tissue engineering. Since the structural and compositional properties of the scaffold are major players that determine the efficacy of bone regeneration, the present study focuses on the functionalization of nanostructured carbonated hydroxyapatite (nCHA) and cellulose nanofibril (CNF) in porous poly(ε-caprolactone) (PCL)-based bone scaffold, featuring a lamellar-cellular dual porous architecture. In this study, the scaffold fabricated using the freezedrying technique formed a dual porous architecture comprising lamellar and cellular structures. The introduction of nCHA and CNF significantly reconstructed the scaffold structure, increasing porosity. The mechanical properties of the porous scaffold containing nCHA and CNF resembled those of native cancellous bone. Moreover, the swelling and degradation performance of the composite scaffolds exhibited a rapid increase following the
incorporation of nCHA and CNF, which, in turn, enhanced the rate of protein adsorption. The intrinsic antibacterial properties of nCHA and CNF significantly enhanced the antibacterial activity of the composite scaffold
against Porphyromonas gingivalis and Staphylococcus aureus. The osteoconductive properties of nCHA promoted the formation of bone-like apatite crystals on the scaffold surface and improved the proliferation and adhesion of
MC3T3-E1 cells. Similarly, the surface hydroxyl groups of CNF contributed to enhanced cell proliferation and
adhesion. Consequently, the PCL/nCHA/CNF scaffold effectively facilitated cell migration. The above results
show the high biocompatibility of PCL/nCHA/CNF scaffold to serve as an alternative scaffold material for bone
tissue engineering.