Biofabrication最新文献

Ultraviolet photopolymerization additive manufacturing has been used to fabricate calcium phosphate (Ca-P) ceramic scaffolds for repairing bone defects, but it is still a challenge for 3D printed Ca-P scaffolds to simultaneously enhance the mechanical strength and osteoinductivity. Here, we successfully developed a high-performance hydroxyapatite (HA) scaffold containing in-situ carbon and graphene oxide (GO) by precisely regulating the degreasing and sintering atmosphere. The results indicated that the mechanical properties of HA scaffolds could be significantly improved by regulating the amount of in-situ carbon. The HA scaffold containing 0.27 wt% carbon achieved the maximum compressive strength of 12.5 MPa with a porosity of approximately 70%. The RNA transcriptome sequencing analysis revealed that in-situ carbon could promote osteogenic differentiation by improving oxygen transport and promoting the expression of multiple angiogenic factors. More importantly, in the absence of osteoinductive agents, the in-situ carbon and GO synergistically promoted more effective bone mineralization, demonstrating enhanced osteoinductivity in vitro. In a rodent model, the bioceramic scaffolds also exhibited improved osteogenesis in critical bone defects. Therefore, in-situ carbon and GO could simultaneously enhance the mechanical strength and osteoinductivity of HA scaffolds, effectively achieving substantial endogenous bone regeneration. This strategy will provide a simple and energy-efficient approach for engineering osteoinductive ceramic scaffolds for repairing bone defects.

3D bioprinting approaches offer highly versatile solutions to replicate living tissue and organ structures. While current bioprinting approaches can generate desired shapes and spatially determined patterns, the material selection for embedded bioprinting has remained limited, as it has relied on the use of viscous, shear-thinning, or liquid-like solid materials to create shape controlled constructs, which could then be modified downstream via multi-step processes. We here explore aqueous two-phase system stabilized 3D bioprinting of low viscous materials in combination with supramolecular complexation to fabricate intricate, perfusable engineered constructs that are both mechanically and chemically tunable in a single-step manner. To this end, we introduce Dex-TAB as a highly versatile backbone, that allows for mechanical and chemical tuning during as well as after printing. Showcasing the printability as well as spatial chemical modification and mechanical tunability of this material, ejectability, and local/gradual or bulk functionalized interconnected tube shaped constructs were generated. Subsequently, we demonstrated that these functionalized channels could be printed directly into a syringe containing crosslinkable polymer solution, which upon ejection forms pre-patterned perfusable constructs. In short, we report that ATPS enabled low viscous 3D bioprinting can produce highly functional and even potentially minimally invasive injectable yet functionalized and perfusable constructs, which offers opportunities to advance various biofabrication applications.

Understanding the intricate structure-function relationships of neuronal circuits is crucial for unraveling how the brain achieves efficient information transfer. In specific brain regions, like the hippocampus, neurons are organized in layers and form unidirectional connectivity, which is thought to help ensure controlled signal flow and information processing. In recent years, researchers have tried emulating these structural principles by providing cultured neurons with asymmetric environmental cues, namely microfluidics' microchannels, which promote directed axonal growth. Even though a few reports have claimed to achieve unidirectional connectivity ofin vitroneuronal circuits, given the lack of functional characterization, it remains unknown if this structural connectivity correlates with functional connectivity. We have replicated and tested the performance of asymmetric microchannel designs previously reported in the literature to be successful in promoting directed axonal growth, as well as other custom variations. A new variation of 'Arrowhead', termed 'Rams', was the best-performing motif with a ∼76% probability per microchannel of allowing strictly unidirectional connections at 14 din vitro. Importantly, we assessed the functional implications of these different asymmetric microchannel designs. For this purpose, we combined custom microfluidics with microelectrode array technology to record the electrophysiological activity of two segregated populations of hippocampal neurons ('Source' and 'Target'). This functional characterization revealed that up to ∼94% of the spiking activity recorded along microchannels with the 'Rams' motif propagates towards the 'Target' population. Moreover, our results indicate that these engineered circuits also tended to exhibit network-level synchronizations with defined directionality. Overall, this functional characterization of the structure-function relationships promoted by asymmetric microchannels has the potential to provide insights into how neuronal circuits use specific network architectures for effective computations. Moreover, the here-developed devices and approaches may be used in a wide range of applications, such as disease modeling or preclinical drug screening.

Patients suffering from large bone defects are in urgent need of suitable bone replacements. Besides biocompatibility, such replacements need to mimic the 3D architecture of bone and match chemical, mechanical and biological properties, ideally promoting ossification. As natural bone mainly contains collagen type I and carbonate hydroxyapatite, a 3D-printable biomaterial consisting of methacrylated gelatin (GelMA) and nanohydroxyapatite (nHAp) would be beneficial to mimic the composition and shape of natural bone. So far, such nanocomposite hydrogels (NCH) suffered from unsatisfactory rheological properties making them unsuitable for extrusion-based 3D printing with high structural fidelity. In this study, we introduce a novel GelMA/nHAp NCH composition, incorporating the rheological modifier carbomer to improve rheological properties and addressing the challenge of calcium cations released from nHAp that hinder GelMA gelation. Leveraging its shear-thinning and self-healing properties, the NCH ink retains its shape and forms cohesive structures after deposition, which can be permanently stabilized by subsequent UV crosslinking. Consequently, the NCH enables the printing of 3D structures with high shape fidelity in all dimensions, including the z-direction, allowing the fabrication of highly macroporous constructs. Both the uncured and the UV crosslinked NCH behave like a viscoelastic solid, with G´>G´´ at deformations up to 100-200 %. After UV crosslinking, the NCH can, depending on the GelMA concentration, reach storage moduli of approximately 10 to over 100 kPa and a mean Young's Modulus of about 70 kPa. The printed scaffolds permit not only cell survival but also osteogenic differentiation, highlighting their potential for bone tissue engineering.

In recent years, biofabrication technologies have garnered significant attention within the scientific community for their potential to create advancedin vitrocancer models. While these technologies have been predominantly applied to model advanced stages of cancer, there exists a pressing need to develop pertinent, reproducible, and sensitive 3D models that mimic cancer initiation lesions within their native tissue microenvironment. Such models hold profound relevance for comprehending the intricacies of cancer initiation, to devise novel strategies for early intervention, and/or to conduct sophisticated toxicology assessments of putative carcinogens. Here, we will explain the pivotal factors that must be faithfully recapitulated when constructing these models, with a specific focus on early pancreatic cancer lesions. By synthesizing the current state of research in this field, we will provide insights into recent advances and breakthroughs. Additionally, we will delineate the key technological and biological challenges that necessitate resolution in future endeavors, thereby paving the way for more accurate and insightfulin vitrocancer initiation models.

Kidney transplantation remains a pivotal treatment modality for kidney disease, yet its progress is significantly hindered by the scarcity of donor kidneys and ethical dilemmas surrounding their procurement. As organoid technology evolves and matures, the creation of bionic human kidney organoids offers profound potential for advancing kidney disease research, drug nephrotoxicity screening, and regenerative medicine. Nevertheless, current kidney organoid models grapple with limitations such as constrained cellular differentiation, underdeveloped functional structures, and a crucial absence of vascularization. This deficiency in vascularization, in particular, stunts organoid development, restricts their size, diminishes filtration capabilities, and may trigger immune inflammatory reactions through the resulting ischemic microenvironment. Hence, the achievement of vascularization within kidney organoids and the successful establishment of functional microvascular networks constitutes a paramount goal for their future progression. In this review, we provide an overview of recent advancements in biotechnology domains, encompassing organ-on-a-chip technology, biomimetic matrices, and bioprinting, with the aim of catalyzing technological breakthroughs that can enhance the vascularization of kidney organoids and broaden their applicability. These technologies hold the key to unlocking the full potential of kidney organoids as a transformative therapeutic option for kidney disease.

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 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.

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.