Bioprinting and Bioink Innovations for 3D-Tissues 2022 Agenda

Conference Registration, Materials Pick-Up, Continental Breakfast and Networking

Analytical and AI Guided Design of Bioinks and 3D Bioprinted Scaffolds
Dimitria Bonizol Camasao, Senior Application Scientist, Rheolution

Formulating functional bioinks and optimizing 3D bioprinted scaffolds often involve time-consuming and costly trial and error approaches. The use of dedicated analytical testing instruments and artificial intelligence (AI) algorithms may significantly accelerate these tasks. In this presentation, we will first introduce the ElastoSens^TM Bio, a nondestructive testing instrument that measures the viscoelasticity of soft biomaterials. We will highlight how its features can bring value to the 3D and 4D bioprinting process, from the formulation of bioinks to the design of bioprinted scaffolds and their time evolution with or without cells. We will then focus on two published cases to exemplify how this technology and AI are currently helping researchers. In the first work developed by a team from University of Victoria (BC), the ElastoSens^TM Bio was used to understand how the architecture of a scaffold produced through an extrusion-based printing affected its viscoelastic properties in terms of fiber size, porosity, pore shape, and bioink composition. In the second work, the testing instrument was used to build and validate an AI model able to predict the polymerization kinetics of a synthetic photocrosslinkable hydrogel (PEGDA). These unique and novel methodologies have the potential to accelerate research in tissue engineering and regenerative medicine, and their translation into clinical practices.

Mid-Morning Coffee, Tea and Networking in the Exhibit Hall

Designing Bioinks For 3D Tissue Bioprinting
Y. Shrike Zhang, Assistant Professor of Medicine, Harvard Medical School, Associate Bioengineer, Division of Engineering in Medicine, Brigham and Women’s Hospital, United States of America

Over the last decade, three-dimensional (3D) bioprinting has offered great versatility to fabricate biomimetic volumetric tissues that are both structurally and functionally relevant. It enables precise control over the composition, spatial distribution, and architecture of the bioprinted constructs, facilitating recapitulation of the delicate shapes and structures of target organs and tissues. In particular, the search for optimal bioink formulations has proven challenging as bioprinting materials must fulfill several, often contradictory requirements. In this talk, I will accordingly discuss our most recent efforts on developing cytocompatible, cell-instructive, and functional bioink formulations aiming at promoting our capacities in the fabrication of engineered tissue constructs. These bioinks, when rationally combined with a series of established or customized bioprinting strategies, not only improve their printability but also enhance the functions of the resulting tissues that are produced.

Decellularized Extracellular Matrix-based Bioinks for Printing Human Tissues
Jinah Jang, Associate Professor, Pohang University of Science And Technology (POSTECH), Korea South

Recent advances in biofabrication techniques have allowed for the fabrication of cardiac tissue models that are similar to the human heart in terms of their structure (e.g., volumetric scale and anatomy) and function (e.g., contractile and electrical properties). The importance of developing techniques for assessing the characteristics of 3D cardiac substitutes in real time without damaging their structures has also been emphasized. In particular, the heart has two primary mechanisms for transporting blood through the body: contractility and an electrical system based on intra- and extracellular calcium ion exchange. This talk will discuss how 3D cardiovascular tissue testing platform could be generated by integrating the concept of bioprinting-assisted tissue engineering and electrical sensing platforms. Combined with recent advances in human pluripotent stem cell technologies, printed human tissues could serve as an enabling platform for studying complex physiology in tissue and organ contexts of individuals.

Networking Lunch in the Exhibit Hall with Exhibitors and Conference Sponsors

Embedded 3D Printing of Dilute Particle Suspensions into Dense Complex Cardiac Fibers
Jeroen Rouwkema, Associate Professor, University of Twente, Netherlands

In order to fabricate functional organoids and microtissues, a high cell density is generally required. As such, the placement of cell suspensions in molds or microwells to allow for cell concentration by sedimentation, is a standard method for the production of organoids and microtissues. Even though molds offer some level of control over the shape of the resulting microtissue, this control is limited as microtissues tend to compact towards a sphere after sedimentation of the cells. 3D bioprinting offers better control over the shape of the resulting structure. However, when using extrusion 3D bioprinting, the self-assembly into organoids can be hampered due to low cell densities or the presence of bio-ink components which interfere with the self-assembly process. Even though the printing of dense cell suspensions without the addition of a biomaterial component in the ink has been reported, extruding dense cellular suspensions is challenging due to potential clogging of the printing nozzle and the exposure of the cells to high shear stresses. To circumvent these limitations, we have developed  a simple and inexpensive embedded printing method to 3D print dense functional tissues using dilute (volume fraction < 10%) aqueous particle suspensions as an ink. These particles can be cells, spheroids, hydrogel beads, or combinations thereof. Using this approach, we have shown the formation of large functional and beating cardiac tissue fibers using human pluripotent stem cells.

Organoids and Complex Cell-based Architectures in Biofabrication and Volumetric Bioprinting
Riccardo Levato, Associate Professor in Translational Bioengineering and Biomaterials, University Medical Center Utrecht, Netherlands

The function of living tissues is intimately linked to their complex architectures. Advances in biofabrication technologies offer unprecedented opportunities to capture salient features of tissue composition and thus guide the maturation of engineered constructs into mimicking functionalities of native organs. In this lecture, the design of novel biofabrication strategies and printable biomaterials to enable the reconstitution of complex 3D structures with precise heterocellular, multi-material and hierarchical composition is discussed. Architectures designed to stimulate the native interaction between multiple (stem) cell types and self-assembled organoids are introduced, with a particular focus on applications in musculoskeletal regeneration and liver tissue engineering. Layerwise hydrogel extrusion and bioprinting, different additive manufacturing technologies, such as melt electrowriting of polymeric microfibers, ceramic plotting and digital light processing lithographic printing, can be combined to create composite, cell-laden constructs that enable integration between engineered hydrogels and hard tissue scaffolds to generate osteochondral grafts. Albeit powerful and versatile, this approach poses relevant limitations on the scalability and production of constructs having clinically relevant size, as well as on the generation of free-form and support free overhanging, porous structures, typically of native anatomy. To overcome these challenges, custom-designed light responsive hydrogels can be sculpted into cell-laden convoluted 3D structures within tens of second, via the development of layerless, volumetric bioprinting  approaches inspired by visible light computed tomography. With such nozzle and shear stress-free, highly rapid cell processing approach a variety of hydrogel-based constructs can be assembled into hydrogel-based actuators for potential applications in soft robotics, or as platforms to enhance cell viability and maturation post-printing, including the shaping of large networks of hepatic epithelial organoids into defined 3D perfusable structures  which exhibit biosynthetic and metabolic functions. Altogether, the combination of the different strengths of advanced bioprinting technologies offers new opportunities for the biofabrication of large, clinically-relevant multi-tissue constructs for regenerative medicine and tissue engineering.

Additive Manufacturing and Nanomaterials-based Platforms For Bone Modeling and Regeneration: Controlling Cell Fate by Combined Compositional and Morphological Cues
Gabriela Graziani, Assistant Professor, Politecnico di Milano, Italy

Bone is a hierarchical tissue, having complex morphology and composition. Hence, new approaches are needed to mimic its characteristics, to obtain bone models as well as for its regeneration. To fulfill these aims, a scaffold or models shall  reproduce as closely as possible the composition of native bone, because mimicking the native tissue permits boosting bone regeneration, and because bone apatite has a critical role in modulating the behavior of both healthy and tumor cells in the models. At the same time, morphological characteristics (i.e. porosity, surface morphology and roughness) are fundamental to determine the mechanical behavior of the model and to provide cues to which cells can react and that influence their morphology, adhesion, proliferation and differentiation. Here we propose new routes for obtaining bone-mimetic materials, by combining additive manufacturing techniques (3d printing and electrospinning) and plasma-assisted deposition of nano-structured coatings (Ionized Jet Deposition). By these techniques, we reproduce the characteristics of the native tissue and guide its regeneration, exploiting biomimicry, morphological and compositional cues and we study their interactions with healthy (MSCs) and tumor (SAOS-2) cells, for applications in bone regeneration and modeling.

Afternoon Coffee and Tea Break in the Exhibit Hall

Mechanobiology in 3D Bioprinting: Importance and Applications
Zackary Wayne Tiedeman, Application Specialist, Optics11Life

3D printing mechanobiology / mechanical characterization of 3D structures / applications, including tissue regeneration.

Network Reception with Beers -- Network and Engage with Colleagues and Exhibitors

Close of Day 1 of the Conference

Morning Coffee, Tea, Pastries and Networking in the Exhibit Hall

(Supra)Molecular Design Enables Advanced Bioinks and Extracellular Matrix Mimietics
Matthew Baker, Assistant Professor, MERLN Institute, Maastricht University, Netherlands

While natural systems have evolved elegant self-assembled materials, the recreation of such materials in a synthetic system remains a challenge. Even more challenging is leveraging these delicate and hierarchically assembled structures for advanced biomedical engineering technologies. Supramolecular materials utilized for tissue engineering often suffer from poor mechanical properties and poor fabrication performance. In order to address these challenges, we set out to create supramolecular hydrogels from benzene-1,3,5-tricarboxamides which could be amenable to cell-culture and 3D fabrication technologies. Due to the dynamic nature of these supramolecular hydrogels, we paid careful attention to strategies to tune the dynamics and viscoelastic parameters of the system, enabling hydrogels with 1D nanofiber features and controllable internal dynamics. By carefully controlling the timescales of the material, we could access ranges that allowed control over cell aggregate formation and 3D printing. Ultimately, due to their self-healing and injectable nature, these materials were amenable to 3D bioprinting, and could be utilized to create complex architectures like a human sized meniscus. Via careful supramolecular design, the cooperative effects of supramolecular hierarchical structure and control over dynamic timescales can lead to highly processable and biomimetic architectures interesting for tissue engineering.

Micro/Nano Engineered Biomaterials for Manufacturing Biomimetic Tissues and Biomedical Applications
Su Ryon Shin, Assistant Professor of Medicine, Harvard Medical School and Brigham and Women’s Hospital, United States of America

Damage and loss to muscles are common for survivors of trauma-related injuries and disease. In cases where a patient has damaged or lost a significant amount of tissues, the body is unable to repair or regain the lost tissue. Current treatment options are limited, and many patients must undergo multiple surgeries, which are costly and bear the significant risk to the patient. However, a few significant challenges in tissue engineering still exist, such as recapitulating the in vitro, 3D hierarchical microarchitecture comprised of multiple cell types and the extracellular matrix (ECM) components of native tissues and achieving the continuous function and viability of engineered tissues after implantation. To create biomimetic tissue constructs, we developed an advanced multi-material bioprinting platform that employs self-healing supporting baths and a programmable microfluidic device, which can easily and quickly switch between different materials, biological reagents, and cells. This advanced bioprinting platform allowed us to fabricate complex geometrical structures such as centimeter-sized biomimetic uni- or bi-cellular tissue constructs. Another challenge is the survival of bioprinted 3D tissue constructs at the injured area, which is fully dependent on the oxygenation derived by its connection to the blood circulation of the host body. Incorporating functional vasculatures or oxygenating biomaterials could potentially solve this problem, as it immediately allows for the perfusion of blood, thus offering instant and ample amounts of oxygen and nutrients. We have developed oxygen-generating biomaterials containing molecules that release oxygen upon hydrolysis that allow the implant to survive their non-perfused phase and enable the continued function and maturation of living implants. The successful development of these innovative systems is expected to improve tissue regeneration significantly.

Conference Programming Continues in the Parallel Space Summit Track