Cellular and nuclear morphology, together with directional alignment, are fundamental determinants of cell function and play critical roles in the formation, organization, and maintenance of functional fibrous connective tissues. In tissue-engineered systems, these characteristics emerge from the combined influence of scaffold microarchitecture and mechanical loading, which regulate cellular mechanosensing, cytoskeletal organization, and extracellular matrix remodeling, thereby directly affecting tissue regeneration outcomes. In this study, the coupled effects of scaffold fiber architecture and uniaxial stretching on scaffold organization and cell morphology were investigated using bilayer electrospun scaffolds composed of an aligned-fiber layer (AFL) that gradually transformed into a random-fiber layer (RFL). Scaffold morphology and strain-induced fiber alignment were characterized by scanning electron microscopy and two-dimensional fast Fourier transform analysis at elongation levels of 0%, 10%, and 20%. Adult human dermal fibroblasts were cultured on both AFL and RFL scaffold surfaces, and cellular and nuclear morphologies were quantified using shape descriptors under both unstretched conditions and sustained uniaxial stretching of 10%. Uniaxial stretching promoted alignment of initially random fibers while preserving the orientation of pre-aligned fiber architectures. At the cellular level, nuclear morphology exhibited little dependence on scaffold architecture under unstretched conditions but showed pronounced sensitivity to applied strain. In contrast, cell morphology was governed primarily by fiber alignment and displayed only limited sensitivity to sustained mechanical loading. These findings indicate that scaffold architecture and mechanical stretching regulate structural organization (from scaffold microstructure to cellular and nuclear morphology) through distinct yet complementary mechanisms. The ability to independently and complementarily control structural and mechanical cues offers an effective design strategy for bilayer or graded scaffolds intended for the regeneration of complex tissue interfaces, where both isotropic and anisotropic cellular organization are required.

Peri-implantitis is characterized by bacterial infection and progressive destruction of surrounding tissues, with limited long-term therapeutic strategies. Although macrophages could have therapeutic effects on peri-implantitis, macrophage-based cell therapies have yet to be widely applied in clinical settings. In this study, we developed a macrophage-based approach using hyaluronic acid (HA)-mediated priming and evaluated its in vitro functions and therapeutic efficacy in a mouse model of peri-implantitis. Mouse spleen-derived macrophages were cultured with HA (1.5, 1.8, or 2.0 MDa), and phenotypes were analyzed by Reverse transcription quantitative polymerase chain reaction (RT-qPCR) (inducible nitric oxide synthase [iNOS], tumor necrosis factor-α [TNFα], vascular endothelial growth factor [VEGF], Dectin-1) and flow cytometry (F4/80, VEGF, Dectin-1). Phagocytic and migratory capacities were evaluated, and endothelial cell (HUEhT-2) migration was examined. In vivo, HA-treated macrophages were locally injected into a ligature-induced peri-implantitis model and assessed histologically. HA treatment of macrophages suppressed M1-related (iNOS, TNF-α) and M2a, b, c-related (Dectin-1) gene expression while enhancing the M2d-related gene (VEGF). Flow cytometry revealed an increased proportion of M2d-like cells (Dectin-1[-]/VEGF[+]). HA priming enhanced macrophage phagocytic and migratory capacities and promoted HUEhT-2 migration. In vivo, the HA-treated macrophage group exhibited reduced fibrotic tissue formation and enhanced alveolar bone regeneration, particularly in the MΦ18 group. HA-mediated priming modulates macrophage phenotype and function, supporting its therapeutic potential.Impact StatementThe treatment for peri-implantitis includes infection control and tissue regeneration. Although macrophages exerting anti-infectious and regenerative activities could mitigate peri-implantitis, macrophage-based cell therapies have not yet been widely applied in clinical settings. In this study, we demonstrated the therapeutic efficacy of hyaluronic acid-primed macrophages in a mouse model of peri-implantitis. Our findings not only provide insights into the establishment of new therapies for peri-implantitis but also potentially enhance clinical applications of macrophage-based cell therapies for a wide range of diseases.

Trophoblast invasion into the decidualized endometrium is an important aspect of blastocyst implantation necessary for a successful pregnancy. There are many processes involving the early implantation and invasion of trophoblast cells into the maternal decidua that are not well described. Here, we describe the development of a microfluidic model of the trophoblast-endometrial interface that can be used to quantify metrics of trophoblast cell invasion, endothelial cell motility, and the influence of decidualization hormones on these processes.

Osteoarthritis (OA) is a progressive, degenerative joint disorder characterized by irreversible loss of articular cartilage, in which NLRP3 inflammasome-mediated chondrocyte pyroptosis and dysregulated Wnt/β-catenin signaling are recognized as central pathological events. This study investigated the potential chondroprotective effects of teriflunomide (TFM) in OA, revealing a repositioning molecular mechanism whereby TFM inhibits NLRP3-dependent pyroptosis through the reactivation of Wnt/β-catenin signaling. In vitro, using immortalized human chondrocyte (HC) cells, TFM markedly inhibited interleukin (IL)-1β-induced NLRP3 inflammasome activation and the subsequent pyroptosis relative to that of vehicle-treated control cells. Concurrently, TFM restored Wnt/β-catenin signaling, as indicated by the recovered expression of β-catenin, c-Myc, and cyclin D1. Furthermore, TFM suppressed IL-1β-induced reactive oxygen species generation and speck formation by apoptosis-associated speck-like protein containing a CARD, thus promoting the functional recovery of chondrocytes. These in vitro results were further corroborated in a rat model of OA (n = 6 per group). TFM administration (30 mg/kg, every other day for 4 weeks) improved joint morphology, alleviated synovitis, and restored cartilage thickness and proteoglycan content relative to those observed in vehicle-treated animals. Collectively, these findings suggest that TFM exerts chondroprotective effects in preclinical models by reactivating Wnt/β-catenin signaling and inhibiting NLRP3-dependent pyroptosis. TFM warrants further investigation as a potential candidate agent for the treatment of patients with OA.

The placental barrier plays a critical role in protecting the fetus from xenobiotics and regulating the maternal-fetal exchange. However, conventional trophoblast cell lines and animal models often fail to accurately recapitulate the key structural and functional features of the human placental barrier. In this study, a novel organ-on-a-chip (OOC) model was developed that integrated human JEG-3 trophoblast organoids with human umbilical vein endothelial cells under combined fluid shear stress and mechanical strain. This configuration supports the self-assembly of a three-dimensional, functional placental barrier. The engineered tissue exhibited essential physiological characteristics, including syncytiotrophoblast marker expression, human chorionic gonadotropin secretion, and enhanced glucose transport activity. This model was used to assess the transbarrier transport of several flavonoid compounds. The results indicated that permeation occurred primarily via passive diffusion, with permeability differences governed mainly by physicochemical properties, such as lipophilicity, rather than molecular size. This integrated OOC platform establishes a biomimetic human placental model that provides a reliable tool for evaluating placental permeability and the potential toxicity risks of complex compounds.

Tissue repair and regeneration represent multifaceted processes involving a coordinated interplay of diverse cell types, growth factors, and cytokines. Following tissue injury, innate immune cells serve as the primary cellular responders that infiltrate the damaged microenvironment, clear cellular debris, and undergo phenotype transitions essential for establishing a proregenerative environment. To facilitate functional recovery, three-dimensional scaffolds are conventionally used to give physical signals and structural support. However, these constructs frequently encounter barriers in host-scaffold integration, potential material cytotoxicity, and the induction of adverse chronic foreign body responses (e.g., chronic inflammation), which continue to hinder their successful clinical translation. In this regard, natural polysaccharides, including hyaluronic acid, alginate, and mannans, represent promising biomaterials for multifunctional scaffold engineering due to their extracellular matrix (ECM)-mimetic properties, high biocompatibility, rapid degradation, and tunable physicochemical characteristics. Moreover, the unique sugar moieties inherent to these polysaccharides can function as pathogen-associated molecular patterns and directly interact with pattern recognition receptors expressed on host immune cells. These receptor-ligand interactions trigger intracellular signaling cascades, driving the secretion of downstream cytokines and chemokines, guiding immune cells toward proregenerative phenotypes, and remodeling the ECM to achieve functional tissue repair. In this review, the dual functionality of natural polysaccharides in tissue engineering is described, emphasizing their role as physical supports and active immunomodulatory platforms in regenerative medicine. We critically evaluate the immuno-active motifs within natural polysaccharides, reveal their receptor-mediated interactions with immune cell subsets, and highlight recently reported polysaccharide constructs across distinct tissue targets. We also outline engineering design principles to modulate the chemical, structural, and biophysical properties of immune-active scaffolds. Furthermore, we explore the clinical progress of these scaffolds, addressing current milestones alongside ongoing regulatory and manufacturing challenges. This review provides key design criteria to guide the rational development of next-generation, immuno-instructive polysaccharide constructs for immune-mediated tissue regeneration.

Organoid technology, as an innovative three-dimensional (3D) cell culture method, has undergone rapid advancement in the fields of tissue engineering and disease model construction in recent years. Using data retrieved from the PubMed database, this study employed bibliometric methods to systematically analyze 774 relevant publications from 2006 to 2026, focusing on research output, national and institutional distribution, collaboration networks, journal and author influence, and keyword evolution. The results show a significant increase in organoid research output, with China and the United States being the main contributing countries, and active international collaboration. Leading institutions, such as Harvard Medical School, occupy prominent positions in this field, with research covering multidisciplinary directions including cell culture, tissue scaffolds, microfluidic chips, and 3D bioprinting. Keyword analysis revealed core hotspots such as cell differentiation, tissue engineering methods, and multipotent stem cells, with 3D printing and induced pluripotent stem cells emerging as new research frontiers. The study indicates that organoid technology demonstrates substantial utility in simulating human tissue microenvironments, advancing precision medicine, and drug screening. Despite challenges related to vascularization, production standardization, and cost constraints, the development of high-throughput screening platforms and the enhancement of international collaboration systems will promote its clinical translation and sustainable development.

The tumor microenvironment (TME) is a complex and dynamic system composed of immune cells, stromal cells, and extracellular matrix (ECM), whose composition and spatial architecture critically influence tumor initiation, progression, invasion, metastasis, and response to immunotherapy. However, traditional research models such as two-dimensional cell coculture, patient-derived xenograft models, and conventional patient-derived organoid (PDO) systems remain limited in simulating the complexity and physiological relevance of the TME. Three-dimensional (3D) bioprinting technology, with its precise spatial control capabilities and advantages in multicellular integration, has emerged as a promising engineering tool for constructing TME-like models with controlled spatial architecture, tunable matrix properties, and programmable multicellular organization. This review examines the principles and capabilities of major 3D bioprinting technologies (extrusion-based, droplet-based, photopolymerization-based) and evaluates their applications in reconstructing key TME features such as matrix remodeling, vascularization, immune cell integration, and drug response modeling with organoids. Importantly, we distinguish between bioprinted organoid-based systems and bioprinted tumor cell models, highlighting their differences in biological fidelity and translational relevance. In addition, challenges including limited integration of PDO, constraints in multicellular coculture, and insufficient long-term functional stability continue to restrict the physiological relevance of these models. Overall, this review provides an engineering-oriented perspective on the current state of bioprinted TME models and outlines practical directions for developing more physiologically relevant platforms for cancer research, drug screening, and precision oncology.

Osteoporosis-associated bone fractures are a leading cause of disability in the elderly population. Developing effective therapeutic strategies to enhance bone repair under osteoporotic conditions remains a major clinical challenge. Increasing evidence indicates that aberrant lineage commitment of mesenchymal stem/stromal cells (MSCs) resident in bone marrow contributes to osteoporosis-related bone loss. However, incomplete understanding of the regulatory mechanisms governing MSC differentiation has limited the development of efficient therapeutic approaches. In this study, we identified micro-RNA-423 (miR-423) as a negative regulator of osteogenic differentiation, and demonstrated that inhibition of miR-423 significantly enhanced osteoblast differentiation of MSCs. To enable in vivo delivery of the miR-423 inhibitor for bone repair, MSC-derived exosomes (MSC-Exo) were used as a delivery vehicle, generating the Exo-miR-423 inhibitor construct. These exosomes were subsequently incorporated into an apatite-coated poly(lactic-co-glycolic acid) scaffold to form an Exo-miR-423 inhibitor/scaffold complex. Implantation of this complex significantly promoted bone healing in a calvarial defect model in ovariectomized mice. Collectively, these findings demonstrate a promising miRNA-modulated, exosome-based tissue engineering strategy for enhancing bone defect and fracture repair under osteoporotic conditions, and highlight its potential for further optimization and translational application.

Multifunctional integrated hydrogels have emerged as advanced biomaterials that integrate diverse functional properties, including bioactivity, mechanical adaptability, controlled drug release, and electrical/magnetic responsiveness, exhibiting substantial potential in tissue regeneration and repair. These hydrogels provide a versatile platform to mimic the complex microenvironment of native tissues, thereby facilitating cell proliferation, differentiation, and tissue remodeling. Despite rapid progress in their design and development, optimizing performance for specific tissues (e.g., bone, cartilage, skin, nerve, myocardium) remains challenging. Current research focuses on innovative design strategies and the incorporation of key functional modules to tailor hydrogels for targeted regenerative applications. Moreover, translating these materials from bench to bedside requires overcoming barriers related to biocompatibility, scalability, regulatory approval, and long-term functional stability. This review comprehensively summarizes recent advances in multifunctional integrated hydrogels, highlights their applications across different tissue regeneration scenarios, and critically evaluates translational challenges. By synthesizing cutting-edge findings, this work aims to guide the development of next-generation smart tissue engineering scaffolds and accelerate their clinical adoption, ultimately advancing regenerative medicine.

Although embryonic chondrogenesis follows conserved developmental stages across mammalian species, the rate of this process varies significantly. We hypothesized that these varying developmental rates could be normalized and modeled by aligning key developmental milestones of articular cartilage: mesenchymal condensation, chondrogenic differentiation, joint interzone formation, cavitation, and primary ossification center formation. A mathematical model was developed in MATLAB by fitting the developmental curves of these key stages in mice, rats, pigs, horses, and humans. Among various mathematical models, a sigmoid curve model demonstrated the best fit, with the highest R2 (0.98 ± 0.02) and lowest residual norm (0.36 ± 0.21) after normalizing for gestation period and femoral condylar width to account for species-specific differences. The model's high predictive accuracy (R2 = 0.98) was further validated using data from rabbits, canines, and sheep. By differentiating the developmental curve equation, we determined the developmental rate for each species. Our results indicate that embryonic chondrogenesis occurs within a relatively narrow window of gestation (11-32%), with rodents exhibiting faster rates than larger animals. This study presents the first mathematical model to quantitatively align embryonic chondrogenesis across mammals. This model has the potential to fill gaps in developmental timelines through rational calculation and by improving the precision of developmental timing, factors that have often been overlooked in the field. As a pioneering effort, this work opens new avenues for cross-species alignment and enhances the accuracy of data related to embryonic chondrogenesis.Impact Statement As the first mathematical model to align chondrogenesis across different mammals, this work has the potential to enhance the consistency and accuracy of data from various species by correcting inaccuracies and supplementing missing information.

Hematopoietic stem and progenitor cells (HSPCs) are precisely organized within specialized bone marrow niches containing hematopoietic and nonhematopoietic cell types. Physiologically accurate human models of this niche environment that include functional HSPCs have been lacking until recently. Using induced pluripotent stem cells (iPSCs) grown in mixed-matrix hydrogels, vascularized three-dimensional human bone marrow organoids (hBMOs) can now be generated that contain mesenchymal, endothelial, and hematopoietic cells, all vital components of the bone marrow niche. While hBMOs have been shown to support engraftment of normal and malignant cells, there are numerous opportunities to use hBMOs for developing a wider experimental toolkit to test gene functions and stress responses. Here, we establish two new applications for the hBMO platform. First, we demonstrate successful engraftment of gene-edited CD34[+] cells from healthy donors, enabling direct investigation of gene-specific effects on human hematopoiesis in a defined microenvironment. Gene-edited engrafted HSPCs are maintained in hBMOs for 7 days and undergo multilineage differentiation. Second, we adapted a method to induce stress erythropoiesis-a response to acute anemia in mice and humans-in hBMOs, resulting in robust expansion of immunophenotypically defined hematopoietic progenitors and erythroid populations. These two advances expand the laboratory uses for hBMOs and establish this system as a versatile platform for studying human hematopoiesis and erythropoiesis, stress responses, and gene functions within a physiologically relevant bone marrow microenvironment.

Artificial intelligence (AI) is increasingly applied to bioink formulation and bioprinting process control in tissue engineering (TE). Yet, translational progress remains constrained by small datasets, limited cross-platform validation, and weak links between computational predictions and biological outcomes. This review critically evaluates experimentally validated AI applications across scaffold-based bone regeneration, spanning materials design, fabrication control, and biological assessment. Physics-informed models are often more robust and generalizable than purely data-driven approaches, whereas transfer learning remains challenging due to variability in cellular responses and fabrication conditions. To address gaps in existing reporting standards, to address gaps in current reporting recommendations, we propose the AI-TE reporting framework, incorporating TE-specific requirements for biological validation, fabrication documentation, and translational readiness. Impact StatementDespite the rapid growth of AI-driven scaffold design for bone regeneration, reproducibility, and validation remain insufficiently addressed across current studies. This review identifies key methodological gaps and synthesizes practical validation and reporting priorities to improve reliability and translational relevance.

Normothermic machine perfusion (NMP) has emerged as a new technique for organ storage before liver transplantation, making viability testing of the organ feasible and possibly allowing for reconditioning of marginal liver grafts. Erythrocytes form a substantial component in the composition of NMP perfusates. The optimal hematocrit (HCT) for preserving organ function during NMP and the effects of the HCT on metabolic graft function and parameters commonly used to determine organ viability are still unclear. We retrospectively analyzed our rat NMP database of 123 perfusions and identified a possible link between HCT and liver damage parameters in 34 cases following a dual perfusion protocol. To further investigate this relationship, we perfused a total of 16 rat livers for 6 h each in our rat liver NMP setup with four different HCTs at 10%, 16%, 22%, and 28%. We performed blood gas analysis and measured common viability and damage parameters such as bile production, lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). In addition, histological analysis, as well as enzyme-linked immunosorbent assay and colorimetric assay analysis for reactive oxygen species, glycogen content, and hypoxia-inducible factor (HIF), was performed. The perfusate HCT significantly impacted ALT and LDH levels during NMP of rat liver grafts, with lower HCT values corresponding to decreased damage parameters. We investigated differentiating oxygenation levels and identified a possible cause for our observations in HIF-1α stabilization in lower HCT groups. Furthermore, we demonstrate that HCT affects key viability parameters such as lactate, pH levels, and bile production. Our findings illustrate the importance of adequate HCT levels during NMP and propose mechanisms influencing the perfusion outcome.Impact StatementNormothermic machine perfusion (NMP) is becoming an increasingly important tool in liver transplantation. We here show in an exploratory setting the importance of an adequate hematocrit for the outcome of liver graft perfusion and its importance in defining hepatic viability parameters during NMP.

Bone regeneration presents a significant clinical challenge due to the complex interplay between biological processes and the local mechanical environment. While polymeric scaffolds are widely utilized for their tunable physicochemical properties, traditional designs often fail to replicate the dynamic mechanical cues required for optimal tissue remodeling. This review critically examines the mechanobiological design of bioinspired polymeric scaffolds. We first categorize native bone mechanics and the role of mechanical stimuli-such as stiffness, fluid shear, and stability-in regulating the fracture healing cascade. We then bridge these biological principles with advanced fabrication strategies, analyzing how natural, synthetic, and composite polymers can be engineered to mimic the hierarchical stiffness and bioactivity of native bone. Furthermore, we discuss the role of computational modeling (e.g., Finite Element Analysis) in predicting scaffold performance and highlight emerging technologies, including 4D printing and piezoelectric scaffolds, which offer time-dependent and mechano-electrical adaptability. Finally, we address current barriers to clinical translation and propose future directions for mechanically adaptive systems that actively guide regeneration.