Fig. 1 | Programming localized anisotropy via biomimetic 4D printing. One-step alignment of cellulose fibrils during hydrogel composite ink printing. a, Schematic of the shear-induced alignment of cellulose fibrils during direct ink writing and subsequent effects on anisotropic stiffness E and swelling strain . b–d, Direct imaging of cellulose fibrils (stained blue) in isotropic (cast) (b), unidirectional (printed) (c) and patterned (printed) (d) samples (scale bar, 200 µm).
Such an assemble offers several key advantages over both traditional commercial purchasing and internal design and manufacture, the most obvious being cost and time savings10. Researchers and clinicians can label commonly employed items where 3D printing may poutlay is roduce viable end products, download designs and within a few hours have the object ready to use. Printed objects may be used as well in conjunction with or to modify off-the-shelf products, for example, custom-designed centrifuge tubes and plate holders. Once the initial discounted, this approach has been demonstrated to achieve significant cost reduction over commercially available laboratory and medical equipment, which can exceed 99%4,8. In addition, aside from computing literacy and initial set-up, no specialist skills are are required in the design and manufacture of objects, unless post-production physical or chemical customization is required. Thus, access to this technology is not restricted by technical ability, but only by a lack of awareness and/or a willingness to embrace such novel technology.
Fig. 2 | FRESH printing of biological structures based on 3D imaging data and functional analysis of the printed parts. (A) A model of a human femur from 3D CT imaging data is scaled down and processed into machine code for FRESH printing. (B) The femur is FRESH printed in alginate, and after removal from the support bath, it closely resembles the model and is easily handled. (C) Uniaxial tensile testing of the printed femur demonstrates the ability to be strained up to 40% and elastically recover. (D) A model of a section of a human right coronary arterial tree from 3D MRI is processed at full scale into machine code for FRESH printing. (E) An example of the arterial tree printed in alginate (black) and embedded in the gelatin slurry support bath. (F) A section of the arterial trees printed in fluorescent alginate (green) and imaged in 3D to show the hollow lumen and multiple bifurcations. (G) A zoomed-in view of the arterial tree shows the defined vessel wall that is <1mmthick and the well-formed lumen. (H) A dark-field image of the arterial tree mounted in a perfusion fixture to position a syringe in the root of the tree. (I) A time-lapse image of black dye perfused through the arterial tree false-colored at time points of 0 to 6 s to show flow through the lumen and not through the vessel wall. Scale bars, 4 mm (B), 10 mm (E), 2.5 mm (F), 1 mm (G), and 2.5 mm (H and I).