Speaker
Description
Photoresponsive gelatin derivatives are among the most used biomaterials to produce bioink and bioresins for biofabrication. The unique thermoreversible gelation properties of gelatin, combined with covalent crosslinking strategies via the incorporation of i.e. acrylates groups offers a broad range of rheological performances suitable for both extrusion and light-based printing applications. This lecture will focus on highlighting the relevance of accurately controlling gelatin-based materials composition and physico-chemical properties for various technique in light based bioprinting. Modulating viscosity and gelation points offered a powerful tool for digital light projection (DLP) fabrication of complex 3D geometries embedding convoluted channels reflecting anatomical features of blood vessels. Moreover, with the advent of ultra-fast volumetric bioprinting (VBP) strategies, which rely on hihglz viscous polymers to prevent cell sedimentation during printing, GelMA and thiol-ene gelatin have greatly facilitated the biofabrication of structures embedding both single cells and organoids, using both single-components gelatins or microgel-based bioresins. At the same time, methods for multi-material printing are needed for broad VBP adoption and applicability. Although converging VBP with extrusion bioprinting in support baths offers a novel, promising solution, further knowledge on the engineering of hydrogels as light-responsive, volumetrically printable baths is needed. Recently, we investigated the tuning of gelatin macromers, in particular leveraging the effect of molecular weight and degree of modification, to overcome these challenges, creating a library of materials for VBP and Embedded extrusion Volumetric Printing (EmVP). Bioresins with tunable printability and mechanical properties are produced, and a novel subset of gelatins and GelMA exhibiting stable shear-yielding behavior offers a new, single-component, ready-to-use suspension medium for in-bath printing, which is stable over multiple hours without needing temperature control. As a proof-of-concept biological application, bioprinted gels are tested with insulin-producing pancreatic cell lines for 21 days of culture. Leveraging a multi-color printer, complex multi-material and multi-cellular geometries are produced, enhancing the accessibility of volumetric printing for advanced tissue models. In future developments, heterocellular and anisotropic tissue models that can be volumetrically produced in a high-throughput fashion could have far-reaching implications for biomedical and pharmaceutical research, paving the way for the next generation of in vitro tissue models.