3D printing

Despite notable progress, 3D bioprinted constructs remain fragile and lack the essential ECM-mimicking features crucial for promoting bioactivity, cell growth, and tissue formation. To address these shortcomings, we devised an innovative technique that reinforces bioprinted constructs with polymeric yarns composed of thousands of nanofibers. Utilizing an in-situ printing process, a continuous strand of nanofibrous yarn was embedded within the core of the extruded bioink to fabricate a 3D printed construct. We optimized the key design parameters of the yarn, bioink, and the printing process, which are necessary for direct bioprinting of a nanoyarn-reinforced 3D construct, which has never been demonstrated before. The hydrophilicity of nanofibrous yarns promoted interfacial interaction with the bioink, while the shear stress developed at the nozzle during extrusion allowed the yarns to be spooled out as a single continuous strand integrated with the bioink. The micron-sized channels within the bundled yarn facilitated cell wicking into the yarn. This has enhanced the ability to manufacture cell-laden structures, whereby live cells are freely incorporated into a highly organized nanofibrous architecture. The resulting construct offers high bioactivity needed for cell regeneration and superior structural integrity required for diverse biomedical and regenerative medicine applications.