Jungst, T. | bioRxiv Science

bioRxiv2024

Optical Fiber-Assisted Printing: A Platform Technology for Straightforward Photopolymer Resins Patterning and Freeform 3D Printing

Light-based 3D printing techniques represent powerful tools, enabling the precise fabrication of intricate objects with high resolution and control. An innovative addition to this set of printing techniques is Optical Fiber-Assisted Printing (OFAP) introduced in this manuscript. OFAP is a platform utilizing a LED-coupled optical fiber (LOF) which selectively crosslinks photopolymer resins. It allows on-the-fly change of parameters like light intensity and LOF velocity during fabrication, facilitating the creation of structures with progressive features and multi-material constructs layer-by-layer. An optimized formulation based on allyl-modified gelatin (gelAGE) with food dyes as photoabsorbers is introduced. Additionally, a novel gelatin-based biomaterial, alkyne-modified gelatin (gelGPE), featuring alkyne moieties, demonstrates near-visible light absorption thus fitting OFAP needs, paving the way for multifunctional hydrogels through thiol-yne click chemistry. Besides 2D patterning, OFAP is transferred to embedded 3D printing within a resin bath demonstrating the proof-of-concept as novel printing technology with potential applications in tissue engineering and biomimetic scaffold fabrication, offering rapid and precise freeform printing capabilities.

bioengineering↗

bioRxiv2023

Volumetric Printing across Melt Electrowritten Scaffolds Fabricates Multi-Material Living Constructs with Tunable Architecture and Mechanics

Major challenges in biofabrication revolve around capturing the complex, hierarchical composition of native tissues. However, individual 3D printing techniques have limited capacity to produce composite biomaterials with multi-scale resolution. Volumetric bioprinting recently emerged as a paradigm-shift in biofabrication. This ultra-fast, light-based technique sculpts cell-laden hydrogel bioresins into three-dimensional structures in a layerless fashion, providing unparalleled design freedom over conventional bioprinting. However, it yields prints with low mechanical stability, since soft, cell-friendly hydrogels are used. Herein, for the first time, the possibility to converge volumetric bioprinting with melt electrowriting, which excels at patterning microfibers, is shown for the fabrication of tubular hydrogel-based composites with enhanced mechanical behavior. Despite including non-transparent melt electrowritten scaffolds into the volumetric printing process, high-resolution bioprinted structures were successfully achieved. Tensile, burst and bending mechanical properties of printed tubes were tuned altering the electrowritten mesh design, resulting in complex, multi-material tubular constructs with customizable, anisotropic geometries that better mimic intricate biological tubular structures. As a proof-of-concept, engineered vessel-like structures were obtained by building tri-layered cell-laden vessels, and features (valves, branches, fenestrations) that could be resolved only by synergizing these printing methods. This multi-technology convergence offers a new toolbox for manufacturing hierarchical and mechanically tunable multi-material living structures.

bioengineering↗