Biofabrication最新文献

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.

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.

The objective of this review is to deepen understanding and emphasize scientific and technological progress in the transformation of crop by-products into bio-based dental materials. Amid heightened environmental sustainability consciousness, various sectors including dentistry have achieved novel advancements by utilizing bio-based materials from crop by-products for dental restorations. This paper provides a thorough review of the extraction, processing, and application of natural polymers, biopolymers, and bio-based mixtures at both the macroscopic and nanoscopic scales, with a focus on their contextualization within dental practices. The performance and efficacy of bio-resins, bio-sourced monomers, and biopolymers derived from these resources were scrutinized and compared with traditional petroleum-based counterparts. This study addresses the recycling and industrial valorization of bio-based dental materials, emphasizing their potential to foster a circular economy in dentistry.

Biomimetic gut models show promise for enhancing our understanding of intestinal disorder pathogenesis and accelerating therapeutic strategy development. Current in vitro models predominantly comprise traditional static cell culture and animal models. Static cell culture lacks the precise control of the complex microenvironment governing human intestinal function. Animal models provide greater microenvironment complexity but fail to accurately replicate human physiological conditions due to interspecies differences. As the available models do not accurately reflect the microphysiological environment and functions of the human intestine, their applications are limited. An optimal approach to intestinal modelling is yet to be developed, but the field will probably benefit from advances in biofabrication techniques. This review highlights biofabrication strategies for constructing biomimetic intestinal models and research approaches for simulating key intestinal physiological features. We also discuss potential biomedical applications of these models and provide an outlook on multi-scale intestinal modeling.

Best cosmetic outcomes of breast reconstruction using tissue engineering techniques rely on the scaffold architecture and material, which are currently both to be determined. This study suggests an approach for a rational design of breast-shaped scaffold architecture, in which structural analysis is implemented to predict its stiffness and adjust it to that of the native tissue. This approach can help achieve the goal of optimal scaffold architecture for breast tissue engineering. Based on specifications defined in a preliminary implantation study of a non-rationally designed scaffold, and using analytical modeling and finite element analysis, we rationally designed a polycaprolactone made, 3D-printed, highly porous, breast-shaped scaffold with a stiffness similar to the breast adipose tissue. This scaffold had an architecture of a double-shelled dome connected by pillars, with no bottom to allow direct contact of its fat graft with the host's blood vessels (shelled hemisphere adaptive design (SHAD)). To demonstrate the potential of the SHAD scaffold in breast tissue engineering, a proof-of-concept study was performed, in which SHAD scaffolds were embedded with human adipose derived mesenchymal stem cells, isolated from lipoaspirates, and implanted in nod-scid-gamma mouse model with a delayed fat graft injection. After 4 weeks of implantation, the SHAD implants were vascularized with a viable fat graft, indicating the suitability of the SHAD scaffold for breast tissue engineering.

Bioprinting is currently the most promising method to biofabricate complex tissuesin vitrowith the potential to transform the future of organ transplantation and drug discovery. Efforts to create such tissues are, however, almost exclusively based on animal-derived materials, such as gelatin methacryloyl, which have demonstrated efficacy in bioprinting of complex tissues. While these materials are already used in clinical applications, uncertainty about their safety still remains due to their animal origin. Alternatively, synthetic bioinks have been developed that match the printability of natural bioinks but lack their biological complexity, and thereby often fail to support cell growth and facilitate tissue formation. Additionally, most synthetic materials do not meet the mechanical demands of bioprint stable constructs while providing a suitable environment for cells to grow, limiting the number of available bioinks. To bridge this gap and synergize bioprinting and 3D cell culture, we developed a polyethylene glycol-based bioink system to promote the growth and spreading of cell spheroids that consist of human primary endothelial cells and fibroblasts. The 3D bioprinted centimeter-scale constructs have a high shape fidelity and accelerated softening to provide sufficient space for cells to grow. Adjusting the rate of degradability, induced by the integration of ester-functionalized crosslinkers in addition to protease cleavable crosslinkers into the hydrogel network, improves the growth of spheroids in larger printed hydrogel constructs containing an interconnected channel structure. The perfusable constructs enable extensive spheroid sprouting and the formation of a cellular network upon fusion of sprouts as initial steps toward tissue formation with the potential for clinical translation.

One of the major challenges in the way of better fabricating vascularized adipose organoids is the destructive effect of adipogenic differentiation on preformed vasculature, which probably stems from the discrepancy between thein vivophysiological microenvironment and thein vitroculture conditions. As an intrinsic component of adipose tissue (AT), adipose tissue-derived extracellular vesicles (AT-EVs) have demonstrated both adipogenic and angiogenic ability in recent studies. However, whether AT-EVs could be employed to coordinate the angiogenesis and adipogenesis in the vascularization of adipose organoids remains largely unexplored. Herein, we present an efficient method for isolating higher-purity AT-EV preparations from lipoaspirates, and verify the superiority of AT-EV preparations' angiogenic and adipogenic capabilities over those from unpurified lipoaspirates. Next, in the spheroid culture model, it was discovered that the addition of AT-EVs could effectively improve the aggregation through enhancing intercellular adhesion of monoculture spheroids composed of human umbilical vascular endothelial cells (HUVECs), and helped produce vascularized adipose organoids with proper lipolysis and glucose uptake ability in the coculture spheroids comprised of adipose-derived stem cells (ADSCs) and HUVECs. Subsequently, it was observed that AT-EVs could exert a retaining effect on the vasculature of prevascularized coculture spheroids cultured in an adipogenic environment, compared to the reduced vascular networks where AT-EVs were absent. Altogether, these results indicate that AT-EVs, by means of releasing bioactive molecules that emulate thein vivomicroenvironment, can modify non-replicativein vitromicroenvironments, coordinatein vitroadipogenesis and angiogenesis, and facilitate the fabrication of vascularized adipose organoids.

The vascular tissue, as an integral component of the human circulatory system, plays a crucial role in retaining normal physiological functions within the body. Pathologies associated with the vasculature, whether direct or indirect, also constitute significant public health concerns that afflict humanity, leading to the wide studies on vascular physiology and pathophysiology. Given the precious nature of human derived vascular tissue, substantial efforts have been dedicated to the construction of vascular models. Due to the high cost associated with animal experimentation and the inability to directly translate results to human, there is an increasing emphasis on the use of primary human cells for the development ofin vitrovascular models. For instance, obtaining an ApoE^-/-mouse model for atherosclerosis research typically requires feeding a high-fat diet for over 10 weeks, whereasin vitrovascular models can usually be formed within 2 weeks. With advancements in microfluidic technology,in vitrovascular models capable of precisely emulating the hemodynamic environment within human vessels are becoming increasingly sophisticated. Microfluidic vascular models are primarily constructed through two approaches: (1) directly constructing the vascular models based on the three-layer structure of the vascular wall; (2) co-culture of endothelial cells and supporting cells within hydrogels. The former is effective to replicate vascular tissue structure mimicking vascular wall, while the latter has the capacity to establish microvascular networks. This review predominantly presents and discusses recent advancements in template design, construction methods, and potential applications of microfluidic vascular models based on polydimethylsiloxane (PDMS) soft lithography. Additionally, some refined methodologies addressing the limitations of conventional PDMS-based soft lithography techniques are also elaborated, which might hold profound importance in the field of vascular tissue engineering on microfluidic chips.

Bone tissue engineering (BTE) seeks to overcome the limitations of traditional bone repair methods, such as autografts and allografts, which are often limited by availability, donor-site morbidity, immune rejection, and infection risks. Recent advancements have highlighted the potential of spheroids or microtissues as building blocks for BTE. This study aimed to investigate the osteogenic differentiation of spheroids formed from human periosteum-derived cells (hPDCs) and bone marrow-derived mesenchymal stromal cells (hBMSCs) in a hyaluronic acid methacrylate (HAMA) matrix, using encapsulation and extrusion bioprinting methods. Results showed significant morphological changes, high viability, and osteogenic differentiation of spheroids from hPDCs or hBMSCs in three-dimensional HAMA environments. Notably, hPDC spheroids demonstrated higher mineralization capabilities and superior hydrogel colonization than hBMSC spheroids. These findings reveal the potential of HAMA bioink containing hPDC spheroids to produce mineralized bone grafts using a bioprinting approach.