Rapid Tissue Perfusion Using Sacrificial Percolation of Anisotropic Networks.

Tissue engineering has long sought to rapidly generate perfusable vascularized tissues with vessel sizes spanning those seen in humans. Current techniques such as biological 3D printing (top-down) and cellular self-assembly (bottom-up) are resource intensive and have not overcome the inherent tradeoff between vessel resolution and assembly time, limiting their utility and scalability for engineering tissues. We present a flexible and scalable technique termed SPAN - Sacrificial Percolation of Anisotropic Networks, where a network of perfusable channels is created throughout a tissue in minutes, irrespective of its size. Conduits with length scales spanning arterioles to capillaries are generated using pipettable alginate fibers that interconnect above a percolation density threshold and are then degraded within constructs of arbitrary size and shape. SPAN is readily used within common tissue engineering processes, can be used to generate endothelial cell-lined vasculature in a multi-cell type construct, and paves the way for rapid assembly of perfusable tissues.

Rapidly Degrading Hydrogels to Support Biofabrication and 3D Bioprinting Using Cartilage Microtissues.

In recent years, there has been increased interest in the use of cellular spheroids, microtissues, and organoids as biological building blocks to engineer functional tissues and organs. Such microtissues are typically formed by the self-assembly of cellular aggregates and the subsequent deposition of a tissue-specific extracellular matrix (ECM). Biofabrication and 3D bioprinting strategies using microtissues may require the development of supporting hydrogels and bioinks to spatially localize such biological building blocks in 3D space and hence enable the engineering of geometrically defined tissues. Therefore, the aim of this work was to engineer scaled-up, geometrically defined cartilage grafts by combining multiple cartilage microtissues within a rapidly degrading oxidized alginate (OA) supporting hydrogel and maintaining these constructs in dynamic culture conditions. To this end, cartilage microtissues were first independently matured for either 2 or 4 days and then combined in the presence or absence of a supporting OA hydrogel. Over 6 weeks in static culture, constructs engineered using microtissues that were matured independently for 2 days generated higher amounts of glycosaminoglycans (GAGs) compared to those matured for 4 days. Histological analysis revealed intense staining for GAGs and negative staining for calcium deposits in constructs generated by using the supporting OA hydrogel. Less physical contraction was also observed in constructs generated in the presence of the supporting gel; however, the remnants of individual microtissues were more observable, suggesting that even the presence of a rapidly degrading hydrogel may delay the fusion and/or the remodeling of the individual microtissues. Dynamic culture conditions were found to modulate ECM synthesis following the OA hydrogel encapsulation. We also assessed the feasibility of 3D bioprinting of cartilage microtissues within OA based bioinks. It was observed that the microtissues remained viable after extrusion-based bioprinting and were able to fuse after 48 h, particularly when high microtissue densities were used, ultimately generating a cartilage tissue that was rich in GAGs and negative for calcium deposits. Therefore, this work supports the use of OA as a supporting hydrogel/bioink when using microtissues as biological building blocks in diverse biofabrication and 3D bioprinting platforms.

Aided Porous Medium Emulsification for Functional Hydrogel Microparticles Synthesis.

Despite the substantial advancement in developing various hydrogel microparticle (HMP) synthesis methods, emulsification through porous medium to synthesize functional hybrid protein-polymer HMPs has yet to be addressed. Here, the aided porous medium emulsification for hydrogel microparticle synthesis (APME-HMS) system, an innovative approach drawing inspiration from porous medium emulsification is introduced. This method capitalizes on emulsifying immiscible phases within a 3D porous structure for optimal HMP production. Using the APME-HMS system, synthesized responsive bovine serum albumin (BSA) and polyethylene glycol diacrylate (PEGDA) HMPs of various sizes are successfully synthesized. Preserving protein structural integrity and functionality enable the formation of cytochrome c (cyt c) - PEGDA HMPs for hydrogen peroxide (H2O2) detection at various concentrations. The flexibility of the APME-HMS system is demonstrated by its ability to efficiently synthesize HMPs using low volumes (≈50 µL) and concentrations (100 µm) of proteins within minutes while preserving proteins' structural and functional properties. Additionally, the capability of the APME-HMS method to produce a diverse array of HMP types enriches the palette of HMP fabrication techniques, presenting it as a cost-effective, biocompatible, and scalable alternative for various biomedical applications, such as controlled drug delivery, 3D printing bio-inks, biosensing devices, with potential implications even in culinary applications.

Biomimetic design and integrated biofabrication of an in-vitro three-dimensional multi-scale multilayer cortical model.

The lack of accurate and reliable in vitro brain models hinders the development of brain science and research on brain diseases. Owing to the complex structure of the brain tissue and its highly nonlinear characteristics, the construction of brain-like in vitro tissue models remains one of the most challenging research fields in the construction of living tissues. This study proposes a multi-scale design of a brain-like model with a biomimetic cortical structure, which includes the macroscopic structural features of six layers of different cellular components, as well as micrometer-scale continuous fiber structures running through all layers vertically. To achieve integrated biomanufacturing of such a complex multi-scale brain-like model, a multi-material composite printing/culturing integrated bioprinting platform was developed in-house by integrating cell-laden hydrogel ink direct writing printing and electrohydrodynamic fiber 3D printing technologies. Through integrated bioprinting, multi-scale models with different cellular components and fiber structural parameters were prepared to study the effects of macroscopic and microscopic structural features on the directionality of neural cells, as well as the interaction between glial cells and neurons within the tissue model in a three-dimensional manner. The results revealed that the manufactured in vitro biomimetic cortical model achieved morphological connections between the layers of neurons, reflecting the structure and cellular morphology of the natural cortex. Micrometer-scale (10 µm) cross-layer fibers effectively guided and controlled the extension length and direction of the neurites of surrounding neural cells but had no significant effect on the migration of neurons. In contrast, glial cells significantly promoted the migration of surrounding PC12 cells towards the glial layer but did not contribute to the extension of neurites. This study provides a basis for the design and manufacture of accurate brain-like models for the functionalization of neuronal tissues.

Manufacture Dependent Differential Biodegradation of 3D Printed Shape Memory Polymers.

In the field of tissue engineering, 3D printed shape memory polymers (SMPs) are drawing increased interest. Understanding how these 3D printed SMPs degrade is critical for their use in the clinic, as small changes in material properties can significantly change how they behave after in vivo implantation. Degradation of 3D printed acrylated poly(glycerol-dodecanedioate) (APGD) was examined via in vitro hydrolytic, enzymatic, and in vivo subcutaneous implantation assays. Three APGD manufacturing modalities were assessed to determine differences in degradation. Material extrusion samples showed significantly larger mass and volume loss at 2 months, compared to lasercut and vat photopolymerization samples, under both enzymatic and in vivo degradation. Critically, melt transition temperatures of degraded PGD increased over time in vitro, but not in vivo. Histology of tissue surrounding APGD implants showed no significant signs of inflammation compared to controls, providing a promising outlook for use of 3D printed APGD devices in the clinic.

Bioinks and biofabrication techniques for biosensors development: A review.

3D bioprinting technologies and bioink development are enabling significant advances in miniaturized and integrated biosensors. For example, bioreceptors can be immobilized within a porous 3D structure to significantly amplify the signal, while biocompatible and mechanically flexible systems uniquely enable wearable chem- and bio-sensors. This advancement is accelerating translation by enabling the production of high performance, reproducible, and flexible analytical devices. The formulation of the bioink plays a crucial role in determining the bio-functionality of the resulting printed structures, e.g., the porosity that allows the analyte to diffuse through the 3D structure, the affinity and avidity of the receptors, etc. This review explores the next generation of advanced bioinks for biosensor development and provides insights into the latest cutting-edge bioprinting technologies. The bioprinting methods available for biosensor fabrication including inkjet, extrusion, and laser-based bioprinting, are discussed. The advantages and limitations of each method are analysed, and recent advancements in bioprinting technologies are presented. The review then delves into the properties of advanced bioinks, such as biocompatibility, printability, stability, and applicability. Different types of advanced bioinks are explored, including multicomponent, stimuli-responsive, and conductive bioinks. Finally, the next generation of bioinks for biosensors is considered, identifying possible new opportunities and challenges. Overall, this literature review highlights the combined importance of bioink formulation and bioprinting methods for the development of high-performance analytical biosensors.

Dynamic and Static Workout of In Vitro Skeletal Muscle Tissue through a Weight Training Device.

Enhancing muscle strength through workouts is a key factor in improving physical activity and maintaining metabolic profiles. The controversial results concerning the impacts of weight training often arise from clinical experiments that require controlled experimental conditions. In this study, a weight training system for a muscle development model is presented, which is capable of performing weight training motions with adjustable weight loads. Through the implementation of cultured skeletal muscle tissue with floating structures and a flexible ribbon, both isotonic (dynamic change in muscle length) and isometric (static in muscle length) exercises can be performed without the deflection of the tissue. Quantitative analysis of contraction force, changes in metabolic processes, and muscle morphology under different weight training conditions demonstrates the effectiveness of the proposed system. Our proposed system holds potential for establishing effective muscle development and for further applications in rehabilitation training methods.

Recent advances of bone tissue engineering: carbohydrate and ceramic materials, fundamental properties and advanced biofabrication strategies ‒ a comprehensive review.

Bone is a dynamic tissue that can always regenerate itself through remodeling to maintain biofunctionality. This tissue performs several vital physiological functions. However, bone scaffolds are required for critical-size damages and fractures, and these can be addressed by bone tissue engineering. Bone tissue engineering (BTE) has the potential to develop scaffolds for repairing critical-size damaged bone. BTE is a multidisciplinary engineered scaffold with the desired properties for repairing damaged bone tissue. Herein, we have provided an overview of the common carbohydrate polymers, fundamental structural, physicochemical, and biological properties, and fabrication techniques for bone tissue engineering. We also discussed advanced biofabrication strategies and provided the limitations and prospects by highlighting significant issues in bone tissue engineering. There are several review articles available on bone tissue engineering. However, we have provided a state-of-the-art review article that discussed recent progress and trends within the last 3-5 years by emphasizing challenges and future perspectives.

High-yield extracellular vesicle production from HEK293T cells encapsulated in 3D auxetic scaffolds with cyclic mechanical stimulation for effective drug carrier systems.

Extracellular vesicles (EVs) show promise in drug loading and delivery for medical applications. However, the lack of scalable manufacturing processes hinders the generation of clinically suitable quantities, thereby impeding the translation of EV-based therapies. Current EV production relies heavily on non-physiological two-dimensional (2D) cell culture or bioreactors, requiring significant resources. Additionally, EV-derived ribonucleic acid cargo in three-dimensional (3D) and 2D culture environments remains largely unknown. In this study, we optimized the biofabrication of 3D auxetic scaffolds encapsulated with human embryonic kidney 293 T (HEK293 T) cells, focusing on enhancing the mechanical properties of the scaffolds to significantly boost EV production through tensile stimulation in bioreactors. The proposed platform increased EV yields approximately 115-fold compared to conventional 2D culture, possessing properties that inhibit tumor progression. Further mechanistic examinations revealed that this effect was mediated by the mechanosensitivity of YAP/TAZ. EVs derived from tensile-stimulated HEK293 T cells on 3D auxetic scaffolds demonstrated superior capability for loading doxorubicin compared to their 2D counterparts for cancer therapy. Our results underscore the potential of this strategy for scaling up EV production and optimizing functional performance for clinical translation.

Droplet-based microfluidics for engineering shape-controlled hydrogels with stiffness gradient.

Current biofabrication strategies are limited in their ability to replicate native shape-to-function relationships, that are dependent on adequate biomimicry of macroscale shape as well as size and microscale spatial heterogeneity, within cell-laden hydrogels. In this study, a novel diffusion-based microfluidics platform is presented that meets these needs in a two-step process. In the first step, a hydrogel-precursor solution is dispersed into a continuous oil phase within the microfluidics tubing. By adjusting the dispersed and oil phase flow rates, the physical architecture of hydrogel-precursor phases can be adjusted to generate spherical and plug-like structures, as well as continuous meter-long hydrogel-precursor phases (up to 1.75 m). The second step involves the controlled introduction a small molecule-containing aqueous phase through a T-shaped tube connector to enable controlled small molecule diffusion across the interface of the aqueous phase and hydrogel-precursor. Application of this system is demonstrated by diffusing co-initiator sodium persulfate (SPS) into hydrogel-precursor solutions, where the controlled SPS diffusion into the hydrogel-precursor and subsequent photo-polymerization allows for the formation of unique radial stiffness patterns across the shape- and size-controlled hydrogels, as well as allowing the formation of hollow hydrogels with controllable internal architectures. Mesenchymal stromal cells are successfully encapsulated within hollow hydrogels and hydrogels containing radial stiffness gradient and found to respond to the heterogeneity in stiffness through the yes-associated protein mechano-regulator. Finally, breast cancer cells are found to phenotypically switch in response to stiffness gradients, causing a shift in their ability to aggregate, which may have implications for metastasis. The diffusion-based microfluidics thus finds application mimicking native shape-to-function relationship in the context of tissue engineering and provides a platform to further study the roles of micro- and macroscale architectural features that exist within native tissues.

Personalized compression therapeutic textiles: digital design, development, and biomechanical evaluation.

Physical-based external compression medical modalities could provide sustainable interfacial pressure dosages for daily healthcare prophylaxis and clinic treatment of chronic venous disease (CVD). However, conventional ready-made compression therapeutic textiles (CTs) with improper morphologies and ill-fitting of pressure exertions frequently limit patient compliance in practical application. Therefore, the present study fabricated the personalized CTs for various subjects through the proposed comprehensive manufacturing system. The individual geometric dimensions and morphologic profiles of lower extremities were characterized according to three-dimensional (3D) body scanning and reverse engineering technologies. Through body anthropometric analysis and pressure optimization, the knitting yarn and machinery variables were determined as the digital design strategies for 3D seamless fabrication of CTs. Next, to visually simulate the generated pressure mappings of developed CTs, the subject-specific 3D finite element (FE) CT-leg modelings with high accuracy and acceptability (pressure prediction error ratio: 11.00% ± 7.78%) were established based on the constructed lower limb models and determined tissue stiffness. Moreover, through the actual in vivo trials, the prepared customized CTs efficiently (Sig. <0.05; ρ = 0.97) distributed the expected pressure requirements referring to the prescribed compression magnitudes (pressure error ratio: 10.08% ± 7.75%). Furthermore, the movement abilities and comfortable perceptions were evaluated subjectively for the ergonomic wearing comfort (EWC) assessments. Thus, this study promotes the precise pressure management and clinical efficacy for targeted users and leads an operable development approach for related medical biomaterials in compression therapy.

Mass Spectrometry of Collagen-Containing Allogeneic Human Bone Tissue Material.

The current paper highlights the active development of tissue engineering in the field of the biofabrication of living tissue analogues through 3D-bioprinting technology. The implementation of the latter is impossible without important products such as bioinks and their basic components, namely, hydrogels. In this regard, tissue engineers are searching for biomaterials to produce hydrogels with specified properties both in terms of their physical, mechanical and chemical properties and in terms of local biological effects following implantation into an organism. One of such effects is the provision of the optimal conditions for physiological reparative regeneration by the structural components that form the basis of the biomaterial. Therefore, qualitative assessment of the composition of the protein component of a biomaterial is a significant task in tissue engineering and bioprinting. It is important for predicting the behaviour of printed constructs in terms of their gradual resorption followed by tissue regeneration due to the formation of a new extracellular matrix. One of the most promising natural biomaterials with significant potential in the production of hydrogels and the bioinks based on them is the polymer collagen of allogeneic origin, which plays an important role in maintaining the structural and biological integrity of the extracellular matrix, as well as in the morphogenesis and cellular metabolism of tissues, giving them the required mechanical and biochemical properties. In tissue engineering, collagen is widely used as a basic biomaterial because of its availability, biocompatibility and facile combination with other materials. This manuscript presents the main results of a mass spectrometry analysis (proteomic assay) of the lyophilized hydrogel produced from the registered Lyoplast® bioimplant (allogeneic human bone tissue), which is promising in the field of biotechnology. Proteomic assays of the investigated lyophilized hydrogel sample showed the presence of structural proteins (six major collagen fibers of types I, II, IV, IX, XXVII, XXVIII were identified), extracellular matrix proteins, and mRNA-stabilizing proteins, which participate in the regulation of transcription, as well as inducer proteins that mediate the activation of regeneration, including the level of circadian rhythm. The research results offer a new perspective and indicate the significant potential of the lyophilized hydrogels as an effective alternative to synthetic and xenogeneic materials in regenerative medicine, particularly in the field of biotechnology, acting as a matrix and cell-containing component of bioinks for 3D bioprinting.

Sustainable biofabrication: from bioprinting to AI-driven predictive methods.

Biofabrication is potentially an inherently sustainable manufacturing process of bio-hybrid systems based on biomaterials embedded with cell communities. These bio-hybrids promise to augment the sustainability of various human activities, ranging from tissue engineering and robotics to civil engineering and ecology. However, as routine biofabrication practices are laborious and energetically disadvantageous, our society must refine production and validation processes in biomanufacturing. This opinion highlights the research trends in sustainable material selection and biofabrication techniques. By modeling complex biosystems, the computational prediction will allow biofabrication to shift from an error-trial method to an efficient, target-optimized approach with minimized resource and energy consumption. We envision that implementing bionomic rationality in biofabrication will render bio-hybrid products fruitful for greening human activities.

Various Antibacterial Strategies Utilizing Titanium Dioxide Nanotubes Prepared via Electrochemical Anodization Biofabrication Method.

Currently, titanium and its alloys have emerged as the predominant metallic biomaterials for orthopedic implants. Nonetheless, the relatively high post-operative infection rate (2-5%) exacerbates patient discomfort and imposes significant economic costs on society. Hence, urgent measures are needed to enhance the antibacterial properties of titanium and titanium alloy implants. The titanium dioxide nanotube array (TNTA) is gaining increasing attention due to its topographical and photocatalytic antibacterial properties. Moreover, the pores within TNTA serve as excellent carriers for chemical ion doping and drug loading. The fabrication of TNTA on the surface of titanium and its alloys can be achieved through various methods. Studies have demonstrated that the electrochemical anodization method offers numerous significant advantages, such as simplicity, cost-effectiveness, and controllability. This review presents the development process of the electrochemical anodization method and its applications in synthesizing TNTA. Additionally, this article systematically discusses topographical, chemical, drug delivery, and combined antibacterial strategies. It is widely acknowledged that implants should possess a range of favorable biological characteristics. Clearly, addressing multiple needs with a single antibacterial strategy is challenging. Hence, this review proposes systematic research into combined antibacterial strategies to further mitigate post-operative infection risks and enhance implant success rates in the future.

Design and evaluation of a bilayered dermal/hypodermal 3D model using a biomimetic hydrogel formulation.

Due to the limitations of the current skin wound treatments, it is highly valuable to have a wound healing formulation that mimics the extracellular matrix (ECM) and mechanical properties of natural skin tissue. Here, a novel biomimetic hydrogel formulation has been developed based on a mixture of Agarose-Collagen Type I (AC) combined with skin ECM-related components: Dermatan sulfate (DS), Hyaluronic acid (HA), and Elastin (EL) for its application in skin tissue engineering (TE). Different formulations were designed by combining AC hydrogels with DS, HA, and EL. Cell viability, hemocompatibility, physicochemical, mechanical, and wound healing properties were investigated. Finally, a bilayered hydrogel loaded with fibroblasts and mesenchymal stromal cells was developed using the Ag-Col I-DS-HA-EL (ACDHE) formulation. The ACDHE hydrogel displayed the best in vitro results and acceptable physicochemical properties. Also, it behaved mechanically close to human native skin and exhibited good cytocompatibility. Environmental scanning electron microscopy (ESEM) analysis revealed a porous microstructure that allows the maintenance of cell growth and ECM-like structure production. These findings demonstrate the potential of the ACDHE hydrogel formulation for applications such as an injectable hydrogel or a bioink to create cell-laden structures for skin TE.

Apoptotic Induction by Biosynthesized Gold Nanoparticles Using Phormidesmis communis Strain AB_11_10 against Osteosarcoma Cancer.

Phormidesmis communis strain AB_11_10 was isolated and identified using microscopy and 16s rRNA sequencing, and its phytochemical constituents were determined using liquid chromatography-quadrupole time-of-flight mass spectrometry. The isolate had a segmented filamentous shape with a blue-green color. Many biomolecules, including organic compounds, amino acids, and fatty acids, were detected. P. communis strain AB_11_10 was used to synthesize gold nanoparticles (Ph-AuNPs) by adjusting the optimum reaction conditions. The concentration, algal/precursor ratio, temperature, reaction time, and pH significantly influenced the synthesis of the Ph-AuNPs. Mixing 1 mL of 0.5 mM of HAuCl4 with 1 mL of algal extract and exposing the mixture to 100 °C for 30 min at pH 5.6 were the optimum conditions for the biosynthesis of Ph-AuNPs at a wavelength of 524.5 nm. The Ph-AuNPs were characterized using TEM, SEM, EDX, and mapping Zeta sizer and FTIR. The Ph-AuNPs had quasi-spherical to triangular shapes with an average diameter of 9.6 ± 4.3 nm. Ph-AuNPs composed of 76.10 ± 3.14% of Au and trace amounts of carbon and oxygen were detected, indicating that the P. communis strain AB_11_10 successfully synthesized Ph-AuNPs. The hydrodynamic diameter of the Ph-AuNPs was 28.5 nm, and their potential charge was -17.7 mV. O-H, N-H, C=C, N-O, C-H, and C-O were coated onto the surfaces of the Ph-AuNPs. These groups correspond to algal phytochemicals, which may have been the main reducing and stabilizing substances during the Ph-AuNP synthesis. The therapeutic activity of the Ph-AuNPs against osteosarcoma cancers was examined in MG-63 and SAOS-2 cell lines, while their biocompatibility was tested against Vero cell lines using a sulforhodamine B assay. The Ph-AuNPs had potent antitumor activity against the MG-63 and SAOS-2 cells, with a low toxicity toward Vero cells. Flow cytometry and cell cycle arrest analyses revealed that the Ph-AuNPs enhanced the apoptotic pathway and arrested the cell cycle in the MG-63 and SAOS-2 cells. P. communis strain AB_11_10 provides a new source to synthesize small, stable, and biocompatible AuNPs that act as apoptotic enhancers in osteosarcoma.

Biofabrication of Living Actuators.

The impact of tissue engineering has extended beyond a traditional focus in medicine to the rapidly growing realm of biohybrid robotics. Leveraging living actuators as functional components in machines has been a central focus of this field, generating a range of compelling demonstrations of robots capable of muscle-powered swimming, walking, pumping, gripping, and even computation. In this review, we highlight key advances in fabricating tissue-scale cardiac and skeletal muscle actuators for a range of functional applications. We discuss areas for future growth including scalable manufacturing, integrated feedback control, and predictive modeling and also propose methods for ensuring inclusive and bioethics-focused pedagogy in this emerging discipline. We hope this review motivates the next generation of biomedical engineers to advance rational design and practical use of living machines for applications ranging from telesurgery to manufacturing to on- and off-world exploration.

Coumarin-Based Photodegradable Hydrogels Enable Two-Photon Subtractive Biofabrication at 300†mm s-1.

Spatiotemporally controlled two-photon photodegradation of hydrogels has gained increasing attention for high-precision subtractive tissue engineering. However, conventional photolabile hydrogels often have poor efficiency upon two-photon excitation in the near-infrared (NIR) region and thus require high laser dosage that may compromise cell activity. As a result, high-speed two-photon hydrogel erosion in the presence of cells remains challenging. Here we introduce the design and synthesis of efficient coumarin-based photodegradable hydrogels to overcome these limitations. A set of photolabile coumarin-functionalized polyethylene glycol linkers are synthesized through a Passerini multicomponent reaction. After mixing these linkers with thiolated hyaluronic acid, semi-synthetic photodegradable hydrogels are formed in situ via Michael addition crosslinking. The efficiency of photodegradation in these hydrogels is significantly higher than that in nitrobenzyl counterparts upon two-photon irradiation at 780 nm. A complex microfluidic network mimicking the bone microarchitecture is successfully fabricated in preformed coumarin hydrogels at high speeds of up to 300 mm s-1 and low laser dosage down to 10 mW. Further, we demonstrate fast two-photon printing of hollow microchannels inside a hydrogel to spatiotemporally direct cell migration in 3D. Collectively, these hydrogels may open new avenues for fast laser-guided tissue fabrication at high spatial resolution.

Advanced optical assessment and modeling of extrusion bioprinting.

In the context of tissue engineering, biofabrication techniques are employed to process cells in hydrogel-based matrices, known as bioinks, into complex 3D structures. The aim is the production of functional tissue models or even entire organs. The regenerative production of biological tissues adheres to a multitude of criteria that ultimately determine the maturation of a functional tissue. These criteria are of biological nature, such as the biomimetic spatial positioning of different cell types within a physiologically and mechanically suitable matrix, which enables tissue maturation. Furthermore, the processing, a combination of technical procedures and biological materials, has proven highly challenging since cells are sensitive to stress, for example from shear and tensile forces, which may affect their vitality. On the other hand, high resolutions are pursued to create optimal conditions for subsequent tissue maturation. From an analytical perspective, it is prudent to first investigate the printing behavior of bioinks before undertaking complex biological tests. According to our findings, conventional shear rheological tests are insufficient to fully characterize the printing behavior of a bioink. For this reason, we have developed optical methods that, complementarily to the already developed tests, allow for quantification of printing quality and further viscoelastic modeling of bioinks.