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Phycocolloids are gelling polysaccharides extracted from algae that have found applications as microbiological culture media, food thickener, and cosmetic rheological modifiers. The extensive use of algae species that have not been yet domesticated has led to overexploitation or supply shortages. Thus, extending the library of phycocolloids would permit to support the industrial changes towards renewable polymer feedstocks but if the source of algae is limited to wild algae species, this might raise issue on the scalability and hinder the creation of a reliable supply chain. In this study, we have identified a new phycocolloid extracted from Chaetomorpha aerea, a green seaweed that can be cultivated in open ponds. Through elucidation of its chemical structure, we propose a gelation mechanism for an extracted sulfated polysaccharide fraction that form stable, transparent hydrogels that can be used for microbiological culture.

In multicellular organisms, cells are organized in a 3-dimensional framework and this is essential for organogenesis and tissue morphogenesis. Systems to recapitulate 3D cell growth are therefore vital for understanding development and cancer biology. Cells organized in 3D environments can evolve certain phenotypic traits valuable to physiologically relevant models that cannot be accessed in 2D culture. Cellular spheroids constitute an important aspect of in vitro tumor biology and they are usually prepared using the hanging drop method. Here a 3D printed approach is demonstrated to fabricate bespoke hanging drop devices for the culture of tumor cells. The design attributes of the hanging drop device take into account the need for high-throughput, high efficacy in spheroid formation, and automation. Specifically, in this study, custom-fit, modularized hanging drop devices comprising of inserts (Q-serts) were designed and fabricated using fused filament deposition (FFD). The utility of the Q-serts in the engineering of unicellular and multicellular spheroids-synthetic tumor microenvironment mimics (STEMs)—was established using human (cancer) cells. The culture of spheroids was automated using a pipetting robot and bioprinted using a custom bioink based on carboxylated agarose to simulate a tumor microenvironment (TME). The spheroids were characterized using light microscopy and histology. They showed good morphological and structural integrity and had high viability throughout the entire workflow. The systems and workflow presented here represent a user-focused 3D printing-driven spheroid culture platform which can be reliably reproduced in any research environment and scaled to- and on-demand. The standardization of spheroid preparation, handling, and culture should eliminate user-dependent variables, and have a positive impact on translational research to enable direct comparison of scientific findings.

Translational Bioinks for 3D Bioprinting 3D‐Bioprinting, a technology at the interface of additive manufacturing, biomaterials and cell biology, is poised to revolutionize regenerative medicine and drug screening. Bioinks are the lynchpin as they bridge bench to bedside. A biology‐based approach to engineering bioinks with pro‐regenerative attributes, with an emphasis on reproducibility, efficiency, and conformance to regulatory standards is essential for paving the way to clinical translation. More details can be found in article number 2103469 by V. Prasad Shastri and co‐workers. [Image: see text]

3D‐bioprinting (3DBP) possesses several elements necessary to overcome the deficiencies of conventional tissue engineering, such as defining tissue shape a priori, and serves as a bridge to clinical translation. This transformative potential of 3DBP hinges on the development of the next generation of bioinks that possess attributes for clinical use. Toward this end, in addition to physicochemical characteristics essential for printing, bioinks need to possess proregenerative attributes, while enabling printing of stable structures with a defined biological function that survives implantation and evolves in vivo into functional tissue. With a focus on bioinks for extrusion‐based bioprinting, this perspective review advocates a rigorous biology‐based approach to engineering bioinks, emphasizing efficiency, reproducibility, and a streamlined translation process that places the clinical endpoint front and center. A blueprint for engineering the next generation of bioinks that satisfy the aforementioned performance criteria for various translational levels (TRL1‐5) and a characterization tool kit is presented., 3D‐bioprinting (3DBP) is a promising technology that serves as a bridge to clinical translation. The translational potential of 3DBP depends on the development of the next generation of bioinks. Translational bioinks need to possess proregenerative attributes, while enabling printing of stable structures that survive implantation and evolve into functional tissue.