3D Bioplotter Research Papers

Ni-Co-Fe-based high-entropy superalloys (HESAs) are fabricated into microlattices via a three-step process: (i) layer-by-layer extrusion of inks containing elemental powders (Ni, Co, Fe, Cr, Ti) and TiAl3 powders; (ii) sintering to densify and homogenize the struts; (iii) aging to achieve a γ/γ’ microstructure. The struts of the microlattices show a nearly pore-free and fully-homogenized microstructure. Increasing the Ti concentration from 4 at% (Al9Co26Cr7Fe16Ni38Ti4) to 9 at% (Al8Co25Cr7Fe15Ni36Ti9) leads to a significant increase in the volume fraction of strengthening γ’ precipitates, from 51 to 78 %. Furthermore, in the Ti-rich composition, the γ’ precipitates exhibit a sharp-edged cubic morphology with larger…

Flexible electrodes are crucial for the widespread application of flexible electronics. Flexible stretchable electrodes are a research hotspot for finding a solution for the inability of flexible electrodes to withstand large deformations. In this study, the suitability of silicone rubber (Ecoflex), carbon nanotube (CNT), and carbon fiber (CF) composite materials for flexible devices and their ratios were evaluated for the first time. 3D-printed electrodes based on fractal structures with tensile insensitivity and high linearity were prepared to achieve integrated stretching of flexible devices. To demonstrate the benefits and impact of fractal structures on electrode performance, we fabricated flexible stretchable electrodes…

Processing-structure-property relationships of 3D-printed multi-scale porous ceramics were investigated. Direct ink writing (DIW) of oil-templated colloidal pastes produced hierarchically porous beta-tricalcium phosphate (TCP) scaffolds. Print architecture and microporosity within filaments were varied, mimicking bone structure. The scaffolds exhibited 60–70 % porosity with interconnected macropores 300–700 μm and microporosity within the filaments at the 10 micron-scale. Varying surfactant and oil concentrations created two micro-pore morphologies – bubble-like pores (emulsion) and channel-like pores (capillary suspension). Emulsion scaffolds were stronger, stiffer and more reliable than capillary suspension scaffolds under both compression and bending. Reducing nozzle diameter and inter-filament distance improved strength and stiffness,…

3D bioprinting has emerged as a viable tool to fabricate 3D tissue constructs with high precision using various bioinks which offer instantaneous gelation, shape fidelity, and cytocompatibility. Among various bioinks, cellulose is the most abundantly available natural polymer & widely used as bioink for 3D bioprinting applications. To mitigate the demanding crosslinking needs of cellulose, it is frequently chemically modified or blended with other polymers to develop stable hydrogels. In this study, we have developed a thermoresponsive, composite bioink using carboxymethyl cellulose (CMC) and agarose in different ratios (9:1, 8:2, 7:3, 6:4, and 5:5). Among the tested combinations, the 5:5…

Subcutaneous delivery of cell therapy is an appealing minimally-invasive strategy for the treatment of various diseases. However, the subdermal site is poorly vascularized making it inadequate for supporting engraftment, viability, and function of exogenous cells. In this study, we developed a 3D bioprinted scaffold composed of alginate/gelatin (Alg/Gel) embedded with mesenchymal stem cells (MSCs) to enhance vascularization and tissue ingrowth in a subcutaneous microenvironment. We identified bio-ink crosslinking conditions that optimally recapitulated the mechanical properties of subcutaneous tissue. We achieved controlled degradation of the Alg/Gel scaffold synchronous with host tissue ingrowth and remodeling. Further, in a rat model, the Alg/Gel…

In the field of tissue engineering, 3D printed shape memory polymers (SMPs) are drawing increased interest. Understanding how these 3D printed SMPs degrade is critical for their use in the clinic, as small changes in material properties can significantly change how they behave after in vivo implantation. Degradation of 3D printed acrylated poly(glycerol-dodecanedioate) (APGD) was examined via in vitro hydrolytic, enzymatic, and in vivo subcutaneous implantation assays. Three APGD manufacturing modalities were assessed to determine differences in degradation. Material extrusion samples showed significantly larger mass and volume loss at 2 months, compared to lasercut and vat photopolymerization samples, under both…

Hydrogel skin grafts provide a moist environment and act as a regenerative template to the newly formed tissue. In this study, we developed 3D-bio-printed hydrogels using methacrylated pectin and methacrylated gelatin together with an antibacterial agent (curcumin), a bioactive agent (Vitamin-C) and fibroblast cells. Curcumin release was almost 10 times higher at pH 7.4 than pH 5.0, and it demonstrated antimicrobial affinity against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The developed 3D-bio-printed hydrogels containing cells and bioactive agents demonstrated high cell viability, cell proliferation, and collagen production, and are promising skin graft candidates for the treatment of full-thickness problematic…

Healing of a damaged tendon-to-bone enthesis occurs through the formation of fibrovascular scar tissue with greatly compromised histological and biomechanical properties instead of the regeneration of a new enthesis due to the lack of graded tissue-engineering zones in the interface during the healing process. In the present study, a structure-, composition-, and mechanics-graded biomimetic scaffold (GBS) coated with specific decellularized extracellular matrix (dECM) (GBS-E) aimed to enhance its cellular differentiation inducibilities was fabricated using a three-dimensional (3-D) bioprinting technique. In vitro cellular differentiation studies showed that from the tendon-engineering zone to the bone-engineering zone in the GBS, the tenogenic differentiation…

The development of the effective 3D printing strategy for diverse functional monomers is still challenging. Moreover, the conventional 3D printing hydrogels are usually soft and fragile due to the lack of an energy dissipation mechanism. Herein, a microsphere mediating ink preparation strategy is developed to provide tailored rheological behavior for various monomer direct ink writings. The chitosan microspheres are used as an exemplary material due to their tunable swelling ratio under the acid-drived electrostatic repulsion of the protonated amino groups. The rheological behaviors of the swollen chitosan microsphere (SCM) are independent on the monomer types, and various functional secondary polymers…

3D bioprinting holds great potential for use in tissue engineering to treat degenerative joint disorders, such as osteoarthritis. However, there is a lack of multifunctional bioinks that can not only support cell growth and differentiation, but also offer protection to cells against injuries caused by the elevated oxidative stress; this conditions is a common characteristic of the microenvironment of the osteoarthritis disease. To mitigate oxidative stress-induced cellular phenotype change and malfunction, an anti-oxidative bioink derived from an alginate dynamic hydrogel was developed in this study. The alginate dynamic hydrogel gelated quickly via the dynamic covalent bond between the phenylboronic acid…