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Library of the mechanical properties of the different GelMA hydrogel formulations and how they affect volumetric printing parameters. A) Schematic representation of the GelMA reaction process and overview of the different parameters involved in the design and tuning of the final bioink or bioresin mechanical properties. Representative (n = 3) photo‐rheology curves for the 90 kDa and the 160 kDa GelMAs with different degrees of modification (40%, 60%, and 80%), at different polymer concentrations (5% w/v, 10% w/v, 15% w/v, and 20% w/v). B) Experimental setup for computational axial lithography, showing a volumetric printed pancreas model. C) Printing light dose comparison between optimal values specific for the different GelMA formulations (5%w/v), and a reference value (90p80 optimal light dose). D) The hydrogel strengths of the various GelMA formulations at different concentrations (values of G’ after 30 seconds of exposure). An increased degree of modification leads to greater hydrogel strength. E) The relationship between hydrogel storage modulus and concentration is different depending on the average molecular weight (values of G’ after 30 seconds of exposure). For the 160 kDa GelMA, with increasing concentration, the storage modulus scales follow a linear trend. Conversely, at lower MW (90 kDa), storage modulus scales follow a power law, as a function of the concentration (n = 3). F) 3D overview of the storage moduli (G’) distribution of the GelMA hydrogels with 160 kDa MW i) and 90 kDa MW, as determined through photo‐rheology (n = 3).
Source publication
Volumetric Bioprinting (VBP), enables to rapidly build complex, cell‐laden hydrogel constructs for tissue engineering and regenerative medicine. Light‐based tomographic manufacturing enables spatial‐selective polymerization of a bioresin, resulting in higher throughput and resolution than what is achieved using traditional techniques. However, meth...
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Bioprinting of microtissues has become a standard technique in medical and biotechnological research, offering a more accurate replication of the in vivo setting than conventional 2D cell culture. However, widespread adoption is limited by the absence of a universally accepted printing benchmark—common in standard fused deposition modeling (FDM) pr...
Citations
... Such a system, when effectively combined with wavelengthspecific photocrosslinking or photodegradation chemistries, can allow in situ photo-bioprinting or photodegradation of multimaterial constructs. [51,52] As a conceptual demonstration of synergistic multi-wavelength projection, we activated each laser wavelength in pulses synchronized with the image sequence displayed on the DMD (illustrated in Figure 8A). For instance, the images for the FaSt-Light and ETH logo were divided into three separate images and synchronized with laser activation at 405, 450, or 520 nm, respectively, to create multicolor image projections ( Figure 8B). ...
Light‐based biofabrication techniques have revolutionized the field of tissue engineering and regenerative medicine. Specifically, the projection of structured light, where the spatial distribution of light is controlled at both macro and microscale, has enabled precise fabrication of complex three dimensional structures with high resolution and speed. However, despite tremendous progress, biofabrication processes are mostly limited to benchtop devices which limit the flexibility in terms of where the fabrication can occur. Here, a Fiber‐assisted Structured Light (FaSt‐Light) projection apparatus for rapid in situ crosslinking of photoresins is demonstrated. This approach uses image‐guide fiber bundles which can project bespoke images at multiple wavelengths, enabling flexibility and spatial control of different photoinitiation systems and crosslinking chemistries and also the location of fabrication. Coupling of different sizes of fibers and different lenses attached to the fibers to project small (several mm) or large (several cm) images for material crosslinking is demonstrated. FaSt‐Light allows control over the cross‐section of the crosslinked resins and enables the introduction of microfilaments which can further guide cellular infiltration, differentiation, and anisotropic matrix production. The proposed approach can lead to a new range of in situ biofabrication techniques which improve the translational potential of photofabricated tissues and grafts.
... While volumetric AM achieves remarkable printing speeds by curing entire volumes in a single step, [73][74][75] integrating multi-material capability typically requires additional extrusion systems, which may introduce design complexity. [76][77][78] In contrast, the DF-μCLIP approach is specifically designed for high-resolution, real-time material switching, enabling finely tuned multi-material gradients with minimal overhead. At the same time, the introduction of intermixed interfaces enhances mechanical properties and potentially transfer properties. ...
Functionally gradient materials emulate nature's ability to seamlessly blend properties through variations in material composition, unlocking advanced engineering applications such as biomedical devices and high‐performance composites. Additive manufacturing, particularly stereolithography, enables sophisticated 3D geometries with diverse materials. However, current stereolithography‐based multi‐material 3D printing is constrained by time‐intensive material switching and compromised interfacial properties. To overcome these challenges, we present dynamic fluid‐assisted micro continuous liquid interface production (DF‐µCLIP), a high‐speed multi‐material 3D printing platform that integrates varying compositions in a fully continuous fashion. By utilizing the polymerization‐free “dead zone”, vliquid resins are seamlessly replenished within a resin bath equipped with dynamic fluidic channels and a synchronized material supply system. DF‐µCLIP achieves ultra‐fast printing speeds of 90 mm/hour with 7.4 µ m pixel‐1 resolution while enabling on‐the‐fly material transitions. This strategy enhances mechanical strength at multi‐material interface through entangled polymer networks and promotes seamless material transitions between distinct materials ilike fragile hydrogels and rigid polymers, addressing interfacial failure caused by mismatch of swelling behavior. Additionally, dynamic material replenishment with real‐time composition control enables continuous gradient printing instead of the conventional step‐wise controlled gradient. Demonstrations include polymers with gradient color transitions and gradient carbon nanotube (CNT) composites with seamlessly varying conductivity.
