Polymeric Hydrogel-Based Multicomponent Inks Incorporated with Lanthanide-Doped Nanoconjugates for Extrusion 3D Printing

Polymeric hydrogel nanocomposites have recently emerged as advanced inks for manufacturing three-dimensional (3D) tissue scaffolds via extrusion-based 3D printing techniques. However, achieving hybrid (bio)ink materials with high printability, tunable functionality, and biocompatibility remains a key challenge to enable patient-specific biofabrication. Here, we describe the development of a new class of photoluminescent hybrid ink materials composed of supramolecularly cross-linked biomaterials (from alginate (AL)- gelatin (GL) hydrogels) incorporated with either RAFT-made synthetic polymer poly(polyethylene glycol methyl ether methacrylate) (PPEGMA)−capped lanthanide (NaYF4:Yb, Tm)-doped nanoparticles (LnNPs) or bare LnNPs, to afford LnNPs@PPEGMA-ALGL or LnNPs-ALGL, respectively. The structural, rheological, and mechanical characterizations of the achieved nanocomposite inks are successfully made via Fourier transform infrared (FTIR) spectroscopy, rheometer, and tensile measurements. Electron microscopy and confocal microscopy studies of their 3D-printed constructs reveal good shape fidelity of the filaments. In particular, the printed scaffold of multicomponent hydrogel ink, LnNPs@PPEGMA-ALGL, exhibits highly homogeneous distribution of luminescent nanoconjugates, whereas in vitro assays confirm its high biocompatibility and cellular adhesion to the scaffold, further suggesting potential 3D bioprinting applications of such hybrid inks.