Biofabrication最新文献

Bioprinting produces personalized, cell-laden constructs for tissue regeneration through the additive layering of bio-ink, an injectable hydrogel infused with cells. Currently, bioprinted constructs are assessed for quality by measuring cellular properties post-production using destructive techniques, necessitating the creation of multiple constructs and increasing the production costs of bioprinting. To reduce this burden, cell properties in bio-ink can be monitored in real-time during printing. We incorporated dielectric impedance spectroscopy (DIS) onto a syringe for real-time measurement of primary chondrocytes suspended in phosphate buffered saline (PBS) using impedance (|Z|) and phase angle (θ) from 0.1 to 25 000 kHz. Cell concentration and viability ranged from 0.1 × 10⁶cells ml^-1to 125 × 10⁶cells ml^-1and from 0%to 94%, respectively. Samples with constant or with changing cell concentration were exposed to various flow conditions from 0.5 to 4 ml min^-1. The background PBS signal was subtracted from the sample, allowing for comparisons across devices and providing insight into the dielectric properties of the cells, and was labeled as |Z_cells| andθ_cells. |Z_cells| shared a linear correlation with cell concentration and viability. Flow rate had minimal effect on our results, and |Z_cells| responded on the order of seconds as cell concentration was altered over time. Notably, sensitivity to cell concentration and viability were dependent on frequency and were highest for |Z_cells| whenθ_cellswas minimized. Cell concentration and viability showed an additive effect on |Z_cells| that was modeled across multiple frequencies, and deconvolution of these signals could result in real-time predictions of cell properties in the future. Overall, DIS was found to be a suitable technique for real-time sensing of cell concentration and viability during bioprinting.

Drug screening is an indispensable procedure in drug development and pharmaceutical research. For cell-based drug testing, cells were treated with compounds at different concentrations, and their responses were measured to assess the compounds' effects on cellular behavior. A concentration gradient test creates a growth environment with different compound concentrations for cultured cells, facilitating faster determination of the compound concentration's effect on cellular responses. However, most concentration gradient tests on cell cultures were carried out manually, which is labor-intensive and time-consuming. Microfluidic technology enables drug screening to be conducted in microstructures, which not only improves efficiency and sensitivity but also reduces reagent usage and operating time. Centrifugal microfluidics utilizes the rotation of a disk platform to perform complex fluid functions such as pumping, metering, and mixing. The complete process can be carried out with a low-cost motor without the need for an expensive pumping system. In this work, a centrifugal platform for drug screening is presented. The microfluidic platform can be divided into two parts. The inner disk features branch structures designed to establish a concentration gradient for cell growth. The outer ring contains fluidics for cell culturing, which can discharge the waste fluid when the nutrient is exhausted and replenish the new culture medium by spinning the platform. In conclusion, the proposed centrifugal platform can provide a rapid generation of the concentration gradients and automate the operation of cell culturing. It provides an efficient and low-cost platform for drug screening.

Idiopathic pulmonary fibrosis (IPF) is a lethal lung disease of unknown etiology. Macrophages are implicated in the fibrotic process, but exhibit remarkable plasticity in the activated immune environmentin vivo, presenting significant challenges as therapeutic targets. To explore the influence of macrophages on IPF and develop macrophage-targeted therapies, we engineered a micro-lung chip with a lung epithelium-interstitium tissue unit to establish a controlled immune environment containing only macrophages. We discovered that macrophages exacerbated inflammation and fibrosis by comparing microchips treated with bleomycin (BLM) in the presence and absence of macrophages. Based on the duration of BLM treatment, we established pathological models corresponding to inflammation and fibrosis stages. Transcriptome analysis revealed that activation of the PI3K-AKT signalling pathway facilitates the transition from inflammation to fibrosis. However, LY294002, a PI3K inhibitor, not only suppressed fibrosis and decreased the accumulation of M2 macrophages but also intensified the severity of inflammation. These findings suggest that macrophages play a pivotal role in the potential development at the tissue level. The micro-lung chip co-cultured with macrophages holds significant potential for exploring the pathological progression of IPF and elucidating the mechanisms of anti-fibrotic drugs.

The kidneys are vital for maintaining bodily homeostasis and are susceptible to various diseases that disrupt their function. Traditionally, research on kidney diseases has relied on animal models and simplistic two-dimensional cell cultures, which don't fully replicate human tissue pathology. To address this, recent advances focus on developing advanced 3D biomimetic in vitro models using human-derived cells. These models mimic healthy and diseased kidney tissues with specificity, replicating key elements like glomerular and tubular structures through tissue engineering. By closely mimicking human physiology, they provide a promising platform for studying renal disorders, drug-induced nephrotoxicity, and evaluating new therapies. However, the challenges include optimizing scalability, reproducibility, and long-term stability to enhance reliability in research and clinical applications. This review highlights the transformative potential of 3D biomimetic in vitro kidney models in advancing biomedical research and clinical applications. By focusing on human-specific cell cultures and tissue engineering techniques, these models aim to overcome the limitations of conventional animal models and simplistic 2D cell cultures. The review discusses in detail the various types of biomimetic kidney models currently under development, their specific applications, and the innovative approaches used to construct them. It also addresses the challenges and limitations associated with these models for their widespread adoption and reliability in research settings.

To meet the increasing demand for bone scaffolds, advancements in 3D printing have significantly impacted bone tissue engineering. However, the materials used must closely mimic the biological components and structural characteristics of natural bone tissue. Additionally, constructing complex, oblique structures presents considerable challenges. To address these issues, we explored 3D bioceramic printing using a sanitizer-based hydrogel. Collagen, a primary component of the bone extracellular matrix (ECM), was combined with alpha-tricalcium phosphate (α-TCP) to create the bioceramic ink. The sanitizer-based hydrogel was chosen as the gel bath due to its carbopol content, which provides hydrogel-like support, and ethanol, which coagulates collagen and maintains the integrity of the 3D-printed structure. Theα-TCP/collagen bioceramic ink was printed within the sanitizer-based hydrogel, then collected, immersed in ethanol, and finally submerged in phosphate-buffer saline to initiate a self-setting reaction that convertedα-TCP into calcium-deficient hydroxyapatite. The results demonstrated that complex ceramic/ECM structures could be successfully printed in the sanitizer bath, exhibiting excellent mechanical characteristics. Additionally, scaffolds printed in the sanitizer bath showed higher levels of cell growth and osteogenic activity compared to those produced with onlyα-TCP in an open-air environment. This bioceramic printing approach has a strong potential for constructing complex scaffolds with enhanced osteogenic potential for bone regeneration.

Reconstructive surgery following breast cancer ablation is a surgical gold standard and of increasing importance, but current options comprising autogenous fatty tissue transfer and artificial soft tissue implants are inferior. With the advent of powerful biofabrication technologies like bioprinting, researchers for the first time have the tools to engineer life-like tissues with the ultimate goal of clinical application. In this work, we apply multi-material stereolithographic bioprinting together with a novel sacrificial biomaterial system to engineer complex fatty tissue constructs. Biomaterials, cellular composition and cultivation conditions of these constructs were designed to enable in vitro creation of vascularised fatty tissue. Cells within the constructs showed an overall good survival (>93%) indicated by Calcein-AM staining for living cells and cytotoxicity levels below 7 % (PI-positivity), which even decreased during The constructs showed highay significant increase in cellular viability and activity overthe entire cultivation the culture period of 27 days. Bioprinted aAdipose-derived stem cells were successfully differentiated into adipocytes in situ and expressed PPARy as well as FABP4. Additionally, secretion of adipokines leptin and adiponectin into culture supernatants increased significantly. Endothelial cells vascularised the constructs, creating macro- and microvascular structures within the printed channels and extending beyond with culture time. Multi-modal imaging revealed dynamic cell activitymigration of cells within the bioprinted constructs and signs of progressing maturation towards fatty tissue. Moreover, cells invaded into the surrounding hydrogel. The engineered fatty tissue constructs could serve as a base to develop patient-specific tissue building blocks with the final goal to achieve an all-natural reconstruction of the breast.

3D bioprinting is rapidly evolving as a transformative technology for constructing biological tissues with precise cell and bioink placement. However, ensuring the quality and viability of bioprinted structures presents significant challenges, highlighting the need for advanced monitoring systems. Our study introduces a space-efficient, non-invasive approach for real-time, in-situ monitoring of cell dispersion in bioprinted constructs. Utilizing a novel in-situ fluorescence microscopy technique, we employ nanoparticles for cell tagging and integrate a compact digital microscope into the bioprinter for layer-by-layer imaging, significantly saving space and weight to make the solution adaptable to any commercial bioprinter. This method enhances in-situ analysis by combining data from the fluorescence system with conventional visible spectrum imaging. The synergy of these datasets provides a detailed method to examine cell dispersion and facilitates continuous monitoring during the bioprinting process. This allows for the immediate identification and correction of irregularities in cell deposition. Our approach aims to advance 3D bioprinting, setting new standards for the reliability and efficiency of bioprinted structures.

Organoids have emerged as powerful tools in biomedical research, providing essential models for studying disease mechanisms, drug screening, and personalized medicine. However, most current organoid systems lack mechanical stimuli that are crucial for organ function in vivo. This article discusses the importance of incorporating biomechanics as a fundamental evaluation metric in organoid development. Mechanical forces, such as compression, tension, and fluid shear, are vital for tissue differentiation and function, yet they are absent in many organoid models. We review recent advancements in imaging techniques, such as hierarchical phase-contrast tomography (HiP-CT), that enable detailed mechanical analyses of organoids. Additionally, we propose the use of computational models and novel bioreactors to better simulate in vivo mechanical conditions, enhancing the physiological relevance of organoids. By integrating biomechanics into organoid research, we can improve the predictive power of these models for drug testing and disease modeling, paving the way for more reliable biomedical applications.

Mesenchymal stem cells (MSCs) are pivotal in advancing regenerative medicine; however, the large-scale production of MSCs for clinical applications faces significant challenges related to efficiency, cost, and quality assurance. We introduce the Automated Cell Manufacturing System (Aceman), a revolutionary solution that leverages machine learning and robotics integration to optimize MSC production. This innovative system enhances both efficiency and quality in the field of regenerative medicine. With a modular design that adheres to Good Manufacturing Practice (GMP) standards, Aceman allows for scalable adherent cell cultures. A sophisticated machine learning algorithm has been developed to streamline cell counting and confluence assessment, while the accompanying control software features customization options, robust data management, and real-time monitoring capabilities. Comparative studies reveal that Aceman achieves superior efficiency in analytical and repeatable tasks compared to traditional manual methods. The system's continuous operation minimizes human error, offering substantial long-term benefits. Comprehensive cell biology assays, including Bulk RNA-Seq analysis and flow cytometry, support that the cells produced by Aceman function comparably to those cultivated through conventional techniques. Importantly, Aceman maintains the characteristic immunophenotype of MSCs during automated subcultures, representing a significant advancement in cell production technology. This system lays a solid foundation for future innovations in healthcare biomanufacturing, ultimately enhancing the potential of MSCs in therapeutic applications.

Extrusion-based embedded 3D bioprinting, where bioinks and biomaterials are extruded within a support bath, has greatly expanded the achievable tissue architectures and complexity of biologic constructs that can be fabricated. However, significant scientific, engineering, and process-related challenges remain to recreate the full anatomic structure and physiologic function required for many therapeutic applications. This perspective explores the future advances in extrusion-based embedded 3D bioprinting that could address these challenges, paving the way for clinical translation of bioprinted tissues. .