Three-dimensional plotted alginate fibers embedded with diclofenac and bone cells coated with chitosan for bone regeneration during inflammation

Alginate hydrogel fibers embedded with bone cells and diclofenac were coated with a layer of chitosan hydrogel and made into a porous scaffold by three-dimensional (3D) printing for drug release and bone regeneration. It was hypothesized that the chitosan coating could improve the scaffold's drug retention and release properties and biocompatibility. Macrophage cells were stimulated and cocultured with the scaffold. Tests were conducted to show how the chitosan coating affected the scaffold's drug release efficacy and how the release efficacy affected the cellular activities of stimulated macrophages and bone cells. The bone cells encapsulated in the coated scaffold demonstrated good viability after the acidic/basic coating process. The coating improved the retention and release efficacy of diclofenac and hence significantly inhibited interleukin-6 and tumor necrosis factor- secretion from macrophages (p<0.05). The bone cells in the coated sample mineralized more extensively than the control (p<0.01). They also more actively expressed genes that produce proteins for extracellular matrix remodeling, MMP13, and interacting with the mineral matrix, OPN (both p<0.01). It is believed that on days 7 and 10, when diclofenac was depleted and the concentrations of inflammatory compounds surged, the coating effectively blocked the harmful compounds and protected the bone cells within the fibers. (c) 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1511-1521, 2018.