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. 2021 Oct 5;33(49):2102900. doi: 10.1002/adma.202102900

Figure 3.

Figure 3

Volumetric printing with Gel‐NB. A) Illustration of volumetric printing principle of operation. A 405 nm laser beam (light purple) is directed toward a digital‐micromirror‐device (DMD), which generates dynamically evolving projection images (dark purple) in synchrony with the rotation of the glass vial containing the photosensitive resin. The desired object is solidified where the local light dose accumulation exceeds the gelation threshold. B) Printing parameter optimization using 5% and 2.5% Gel‐NB/PEG4SH resin (DS ≈ 50%). A branch model perfusable with a high‐MW blue‐dextran solution is obtained with a low light dose, corresponding to extremely fast (≈10–11 s) printing (scale bar: 2 mm). C) Print upscaling with 2.5% Gel‐NB/PEG4SH. The potential of fast printing is shown with the generation of replicas of twelve perfusable branch models (left, alternating perfusion with blue‐dextran and TRITC‐dextran) and eight pawn models (right). D) Printing of various 3D complex objects. i) VP with 2.5% Gel‐NB/PEG4SH. From left to right: pawn, rook (top‐left), knight (top‐right), bishop (bottom‐left), and queen (bottom‐right). Due to the hydrogel softness, tall structures such as the bishop and queen models tend to bend when not submerged in liquid. ii) Printing at higher concentration (5% Gel‐NB/PEG4SH) results in stiffer objects that can easily stand (scale bars: 2 mm). E) High cell viability (>90%) after bioprinting is shown for mouse myoblasts (C2C12) and normal human dermal fibroblasts (NHDF) over 1 week of culture in both 5% and 2.5% Gel‐NB/PEG4SH resin. F) Cellular constructs. i) Bioprinting of C2C12‐laden complex free‐form objects with 2.5% Gel‐NB/PEG4SH resin (left, scale bars: 2 mm). Bright‐field close up on cellular construct after 1 week of culture showing cell spreading and proliferation on the soft matrix (right, scale bars: 200 µm). Immunofluorescence evidence of myotubes differentiation after 3 weeks of culture (Myosin Heavy Chain: red, Nuclei: blue, scale bars: 200 µm). ii) Confocal imaging of branch model bioprinted with NHDF‐laden 2.5% Gel‐NB/PEG4SH photoresin and perfused with TRITC‐dextran (red) after 1 week of culture (scale bar: 500 µm).