“From Academia” feature recent, relevant, close to commercialization academic publications in the space of healthcare 3D printing, 3D bioprinting, and related emerging technologies. In this issue, we share three papers focusing on maximizing bioinks palette using complementary thermo-reversible gelatin network, dual-factor releasing and gradient-structuring, and what one-drop 3D printing is.
– Authored by Liliang Ouyang, James P. K. Armstrong, Yiyang Lin, Jonathan P. Wojciechowski, Charlotte Lee-Reeves, Daniel Hachim, Kun Zhou, Jason A. Burdick, Molly M. Stevens. Science Advances. 18 September 2020
A major challenge in three-dimensional (3D) bioprinting is the limited number of bioinks that fulfill the physicochemical requirements of printing while also providing a desirable environment for encapsulated cells. Here, we address this limitation by temporarily stabilizing bioinks with a complementary thermo-reversible gelatin network. This strategy enables the effective printing of biomaterials that would typically not meet printing requirements, with instrument parameters and structural output largely independent of the base biomaterial. This approach is demonstrated across a library of photocrosslinkable bioinks derived from natural and synthetic polymers, including gelatin, hyaluronic acid, chondroitin sulfate, dextran, alginate, chitosan, heparin, and poly(ethylene glycol). A range of complex and heterogeneous structures are printed, including soft hydrogel constructs supporting the 3D culture of astrocytes. This highly generalizable methodology expands the palette of available bioinks, allowing the biofabrication of constructs optimized to meet the biological requirements of cell culture and tissue engineering.
3D bioprinting dual-factor releasing and gradient-structured constructs ready to implant for anisotropic cartilage regeneration
– Authored by Ye Sun, Yongqing You, Wenbo Jiang, Bo Wang, Qiang Wu, Kerong Dai. Science Advances. 9 September 2020.
Cartilage injury is extremely common and leads to joint dysfunction. Existing joint prostheses do not remodel with host joint tissue. However, developing large-scale biomimetic anisotropic constructs mimicking native cartilage with structural integrity is challenging. In the present study, we describe anisotropic cartilage regeneration by three-dimensional (3D) bioprinting dual-factor releasing and gradient-structured constructs. Dual-factor releasing mesenchymal stem cell (MSC)–laden hydrogels were used for anisotropic chondrogenic differentiation. Together with physically gradient synthetic biodegradable polymers that impart mechanical strength, the 3D bioprinted anisotropic cartilage constructs demonstrated whole-layer integrity, lubrication of superficial layers, and nutrient supply in deep layers. Evaluation of the cartilage tissue in vitro and in vivo showed tissue maturation and organization that may be sufficient for translation to patients. In conclusion, one-step 3D bioprinted dual-factor releasing and gradient-structured constructs were generated for anisotropic cartilage regeneration, integrating the feasibility of MSC- and 3D bioprinting–based therapy for injured or degenerative joints.
– Authored by Yu Zhang, Zhichao Dong, Chuxin Li, Huifeng Du, Nicholas X. Fang, Lei Wu & Yanlin Song. Nature Communications. 17 September 2020
3D printing has become one of the most promising methods to construct delicate 3D structures. However, precision and material utilization efficiency are limited. Here, we propose a one-droplet 3D printing strategy to fabricate controllable 3D structures from a single droplet ascribing to the receding property of the three-phase contact line (TCL) of the resin droplet. The well-controlled dewetting force of liquid resin on the cured structure results in the minimization of liquid residue and the high wet and net material utilization efficiency in forming a droplet into a 3D structure. Additionally, extra curing induced protruding or stepped sidewalls under high printing speed, which require high UV intensity, can be prevented. The critical is the free contact surface property of the droplet system with the introduction of the receding TCL, which increased the inner droplet liquid circulation and reduces the adhesion properties among the liquid resin, cured resin, and resin vat.