Shaping Synthetic Multicellular and Complex Multimaterial Tissues via Embedded Extrusion‐Volumetric Printing of Microgels

Abstract

In living tissues, cells express their functions following complex signals from their surrounding microenvironment. Capturing both hierarchical architectures at the micro‐ and macroscale, and anisotropic cell patterning remains a major challenge in bioprinting, and a bottleneck toward creating physiologically‐relevant models. Addressing this limitation, a novel technique is introduced, termed Embedded Extrusion‐Volumetric Printing (EmVP), converging extrusion‐bioprinting and layer‐less, ultra‐fast volumetric bioprinting, allowing spatially pattern multiple inks/cell types. Light‐responsive microgels are developed for the first time as bioresins (µResins) for light‐based volumetric bioprinting, providing a microporous environment permissive for cell homing and self‐organization. Tuning the mechanical and optical properties of gelatin‐based microparticles enables their use as support bath for suspended extrusion printing, in which features containing high cell densities can be easily introduced. µResins can be sculpted within seconds with tomographic light projections into centimeter‐scale, granular hydrogel‐based, convoluted constructs. Interstitial microvoids enhanced differentiation of multiple stem/progenitor cells (vascular, mesenchymal, neural), otherwise not possible with conventional bulk hydrogels. As proof‐of‐concept, EmVP is applied to create complex synthetic biology‐inspired intercellular communication models, where adipocyte differentiation is regulated by optogenetic‐engineered pancreatic cells. Overall, EmVP offers new avenues for producing regenerative grafts with biological functionality, and for developing engineered living systems and (metabolic) disease models.

Embedded 3D bioprinting – An emerging strategy to fabricate biomimetic & large vascularized tissue constructs

“…This approach involves printing multiple bioinks with customized bioprinting systems with multiple bioink stations in a single cartridge or multiple cartridges. Multi-material bioprinting enables precise deposition of various bioinks, containing biomaterials, cells, and other biomolecules to fabricate complex multi-cellular tissue constructs resembling native biological systems [ 84 ]. Various support bath materials, including Pluronics, gelatin, and agarose were used for preparing support baths for embedded multi-material bioprinting [ 34 , 85 ].…”

Multi-material integration in light-based volumetric bioprinting: pathways to enhanced precision and complexity in scaffold fabrication

“…Next, we developed an innovative technique to enable patterning of multiple cell types within volumetrically bioprinted objects 7 . The approach was termed Embedded Extrusion-Volumetric Printing (EmVP), which combined the capabilities of extrusion bioprinting with volumetric bioprinting, and allowed for the fabrication of complex, multicellular, and multi-material tissue constructs with high precision.…”

Contribution of the ELRs to the development of advanced in vitro models

“…Various commonly used 3D bioprinting methods such as extrusion, inkjet, and laser-assisted methods contribute to the precise control of spatial cell distribution and the surrounding microenvironment ( Filipa Duarte Campos et al, 2016 ) (Derakhshanfar et al, n. d.) ( Li et al, 2020 ). Furthermore, innovative approaches such as liquid-in-liquid printing ( Luo et al, 2019 ) (Chen et al, n. d.), 3D Embedded Printing ( Miller et al, 2012 ; Kyle and Jessop, 2017 ; Aazmi et al, 2022 ; Wu et al, 2022a ; Wu et al, 2022b ; Li et al, 2022 ; Budharaju et al, 2024 ), Freeform Reversible Embedding of Suspended Hydrogels (FRESH) printing ( Hinton et al, 2015 ; Lee et al, 2019 ), Suspended Layer Additive Manufacturing (SLAM) ( Grigoryan et al, 2019 ; Noor et al, 2019 ; Senior et al, 2019 ; Shapira et al, 2020 ), and light-based vat-polymerization techniques such as Volumetric bioprinting (VAM) ( Bernal et al, 2019 ; 2022 ; Größbacher et al, 2023 ; Levato et al, 2023 ; Ribezzi et al, 2023 ), have emerged as a potential tool to print soft materials, which is particularly intricate ( Puertas-Bartolomé et al, 2020 ; Budharaju et al, 2024 ).…”