Hydrogel Bioinks of Alginate and Curcumin-Loaded Cellulose Ester-Based Particles for the Biofabrication of Drug-Releasing Living Tissue Analogs

3D bioprinting isa versatile technique that allows the fabricationof living tissue analogs through the layer-by-layer deposition ofcell-laden biomaterials, viz. bioinks. In this work, composite alginatehydrogel-based bioinks reinforced with curcumin-loaded particles ofcellulose esters (CEpCUR) and laden with human keratinocytes (HaCaT)are developed. The addition of the CEpCUR particles, with sizes of740 & PLUSMN; 147 nm, improves the rheological properties of the inks,increasing their shear stress and viscosity, while preserving therecovery rate and the mechanical and viscoelastic properties of theresulting fully cross-linked hydrogels. Moreover, the presence ofthese particles reduces the degradation rate of the hydrogels from26.3 & PLUSMN; 0.8% (ALG) to 18.7 & PLUSMN; 1.3% (ALG:CEpCUR_10%) after3 days in the culture medium. The 3D structures printed with the ALG:CEpCURinks reveal increased printing definition and the ability to releasecurcumin (with nearly 70% of cumulative release after 24 h in PBS).After being laden with HaCaT cells (1.2 x 10(6) cellsmL(-1)), the ALG:CEpCUR bioinks can be successfully3D bioprinted, and the obtained living constructs show good dimensionalstability and high cell viabilities at 7 days post-bioprinting (nearly90%), confirming their great potential for application in fields likewound healing.