Search Results (527)

Articular cartilage is characterized by its avascular, aneural, and alymphatic nature, which confers a limited intrinsic capacity for self-repair. Current regenerative strategies primarily focus on alleviating pain, mitigating symptoms, and restoring joint function. However, their long-term efficacy remains uncertain. Cartilage tissue engineering has emerged as a promising alternative to conventional therapies, offering innovative solutions for articular cartilage regeneration. Central to this approach is the development of functional biomaterials capable of supporting chondrogenic cell adhesion, proliferation, and differentiation, thereby facilitating effective cartilage repair. In this study, we introduce a novel protein-based recombinant spider silk (RSS) as a potential biomaterial for modulating chondrocyte behavior and enabling engineered cartilage formation both in vitro and in vivo. RSS was generated through molecular cloning and processed into silk fibers using biomimetic spinning and acidic coagulation techniques. In micromass cultures of murine chondrocytes, RSS significantly promoted cell aggregation, resulting in increased cell density. Alcian blue and Oil Red O staining demonstrated that RSS-treated cultures produced abundant glycosaminoglycans, a hallmark of chondrogenic activity, while exhibiting minimal lipid accumulation. These findings suggest that RSS supports chondrogenic differentiation and suppresses adipogenic lineage commitment. Real-time PCR analysis revealed upregulation of the chondrogenesis-related gene Sox9 and downregulation of the adipogenic marker PPARγ and the hypertrophic marker Runx2 in RSS-treated micromass cultures. RNA sequencing further corroborated these observations, underscoring the role of RSS in modulating extracellular matrix (ECM) remodeling in chondrocytes. In a subcutaneous transplantation model using severe combined immunodeficiency (SCID) mice, chondrocytes encapsulated in three-dimensional hydrogel scaffolds containing RSS exhibited significantly enhanced ECM accumulation compared to RSS-free controls, indicating that RSS supports the maintenance of the chondrocyte phenotype and promotes cartilage formation in vivo, and underscoring its promising potential as a component of hydrogel composite systems. These findings highlight the potential of RSS as a functional biomaterial to preserve chondrocyte functionality and advance engineered cartilage formation, presenting a promising avenue for cartilage tissue engineering and regeneration. Full article

The development of biomimetic and mechanically functional constructs remains a major challenge in skeletal muscle tissue engineering. In this study, we present a multi-component 3D bioprinted platform integrating a polycaprolactone (PCL) support for mechanical stimulation, a sacrificial gelatin (GE) matrix for controlled bioink deposition, and collagen-based bioinks laden with Rattus norvegicus L6 skeletal muscle cells. The influence of PCL architecture, GE concentration (0.75, 1.5 and 3 wt%), and bioink composition—collagen (C), collagen–Matrigel (CM), and extracellular matrix-based (ECM)—was systematically evaluated. Rheological characterization demonstrated that all bioinks exhibited shear-thinning behavior and suitable viscoelastic properties for extrusion-based bioprinting, with sufficient mechanical stability to withstand dynamic bioreactor conditions. Microstructural analysis revealed highly interconnected porous networks, particularly in ECM-based scaffolds. While no statistically significant differences were observed, the ECM-based bioinks showed the highest cell viability and improved structural organization. Overall, this work demonstrates a versatile bioprinting strategy that combines mechanical support and biomimetic environments, highlighting the potential of ECM-based bioinks for the fabrication of functional skeletal muscle constructs. Full article

Bone tissue engineering requires biomimetic materials; however, pure polylactic acid (PLA) exhibits limited osteoinductivity and produces acidic byproducts upon degradation. To address these limitations, this study fabricated PLA scaffolds using fused-deposition modeling (FDM) with four distinct lattice structures (rectangular, triangular, gyroid, and 3D honeycomb) and incorporated hydroxyapatite (HA) at 0, 10, 20, and 30 wt% via injection molding. Mechanical properties were evaluated via compression, three-point bending, and tensile testing. The results revealed that increasing HA content significantly reduced structural strength and increased brittleness across all test modes. Specifically, specimens with 30 wt% HA exhibited a 70.8% reduction in bending strength relative to pure PLA (from 58.60 MPa to 17.07 MPa), while tensile strength decreased by 46.1% at just 10 wt% HA (from 37.54 MPa to 20.23 MPa). Although the triangular lattice achieved the highest absolute compressive load, the rectangular lattice provided a superior load-to-weight ratio and greater plastic deformation capacity before fracture. Consequently, these findings indicate that the rectangular pattern at 70% infill density combined with HA addition limited to ≤10 wt% represents the most mechanically balanced design for bone defect repair applications. Based on the mechanical characterization performed in this study, and drawing on published evidence regarding the biological properties of PLA/HA composites, these scaffolds represent a mechanically promising candidate for further evaluation in bone tissue regeneration. Biological validation through in vitro and in vivo studies is required before clinical relevance can be established. Full article

Hydrogel scaffolds have emerged as a central platform in tissue engineering due to their ability to mimic the extracellular matrix and support cellular functions. Among natural polymers, chitin and its derivative chitosan have emerged as valuable candidates for hydrogel scaffold development because of their biodegradability, compatibility with living tissues, and inherent biological functionality; however, their distinct and complementary roles in hydrogel scaffold design are often insufficiently differentiated in the literature. This review provides a comprehensive and mechanism-driven analysis of chitin- and chitosan-based hydrogel scaffolds, emphasising how their molecular structure governs network formation, mechanical performance, and biological functionality. Chitin is highlighted primarily as a structurally robust and crystalline component suitable for reinforcement. In contrast, chitosan serves as a versatile, soluble, and chemically reactive matrix enabling various crosslinking and functionalization strategies. Recent advances in physical, ionic, and covalent crosslinking as well as composite scaffold engineering, biofunctionalization, and emerging fabrication approaches such as injectable systems and three-dimensional bioprinting are systematically examined. The relationships between scaffold architecture, degradation behaviour, and cellular responses are discussed in key tissue engineering applications, including bone, cartilage, skin, and nerve regeneration. Importantly, this review introduces a unified structure–property–function framework that distinguishes the roles of chitin and chitosan within hydrogel systems and links crosslinking mechanisms to application-specific performance requirements, an aspect not comprehensively addressed in previous studies. Current challenges related to mechanical limitations, material variability, and clinical translation are critically evaluated, and future perspectives for the rational design of next-generation biomimetic hydrogel scaffolds are proposed. Full article

Background: Impaired angiogenesis and persistent inflammation are hallmarks of chronic diabetic wounds. Extracellular vesicles derived from dental pulp stem cells (DPSC-EVs) represent a promising cell-free therapy for tissue repair; however, their clinical translation is hindered by suboptimal yields and attenuated bioactivity associated with conventional two-dimensional (2D) culture. This study investigated whether a biomimetic three-dimensional (3D) fibrin/gelatin hydrogel system could optimize the therapeutic potency of DPSC-EVs for diabetic wound healing. Methods: DPSCs were encapsulated within 3D fibrin/gelatin scaffolds, followed by comprehensive characterization of cell viability and morphology. 3D-EVs and 2D-EVs were isolated via ultracentrifugation and validated by transmission electron microscopy and nanoparticle tracking analysis. The pro-angiogenic capacity of 3D-EVs was evaluated using human umbilical vein endothelial cells (HUVECs) under high-glucose (HG) stress. Additionally, the immunomodulatory effects were assessed by monitoring macrophage polarization in lipopolysaccharide-stimulated RAW 264.7 cells. The therapeutic efficacy was further validated in vivo using a streptozotocin (STZ)-induced diabetic mouse model with full-thickness cutaneous wounds. Results: The 3D fibrin/gelatin hydrogel provided a supportive microenvironment that significantly augmented the secretory productivity of DPSCs. Compared to 2D-EVs, 3D-EVs exhibited superior functional resilience in restoring HUVEC migration and tube formation under HG-induced oxidative stress. Furthermore, 3D-EVs effectively orchestrated the macrophage transition from a pro-inflammatory M1 phenotype toward an anti-inflammatory M2 phenotype, thereby modulating the immune microenvironment. In vivo, topical administration of 3D-EVs markedly accelerated wound closure, promoted re-epithelialization, and enhanced microvascular density and collagen maturation in diabetic mice. Conclusions: Our findings demonstrate that the 3D fibrin/gelatin culture system effectively primes the therapeutic profile of DPSC-EVs. These engineered vesicles accelerate diabetic wound healing by synergistically promoting angiogenesis and resolving chronic inflammation, offering a robust and potent cell-free strategy for the management of chronic diabetic ulcers. Full article

The limited regenerative capacity of articular cartilage (AC) following injury has led to a high prevalence of degenerative AC-related disorders, including osteoarthritis (OA). Current clinical treatments for OA have failed to halt disease progression, driving growing interest in cartilage tissue engineering (CTE) strategies aimed at developing biomimetic substitutes to regenerate damaged AC tissue. Among the available biofabrication techniques, electrospinning has gained attention due to its ability to generate fibrous scaffolds that closely mimic the architecture of the native AC extracellular matrix, while also serving as versatile drug delivery platforms with high surface area and elevated drug loading efficiency. Small molecules, low-molecular-weight therapeutic agents capable of interacting with both cell membrane and intracellular components, can be incorporated into these scaffold systems to target the underlying mechanisms of OA. This review examines the current state of the art of small molecule-loaded electrospun scaffolds for CTE applications. Small molecules targeting pain, inflammation, and cartilage function restoration show considerable therapeutic potential, and their incorporation into coaxial and other advanced electrospinning setups enables controlled and sustained drug release. Recent examples of small molecule-loaded electrospun scaffolds for AC repair demonstrate enhanced chondrogenic differentiation and neo-cartilage formation, supporting their potential as viable CTE strategies. Nevertheless, challenges related to drug release kinetics, scaffold load-bearing properties, manufacturing scalability, reproducibility, and regulatory approval remain critical barriers to clinical translation. Emerging fabrication strategies, AI-assisted optimization, personalized medicine approaches, and stimuli-responsive drug delivery systems offer promising avenues to overcome these limitations and advance the clinical adoption of these platforms. Full article

Stress urinary incontinence (SUI) affects a significant proportion of women and often requires surgical intervention when conservative treatments fail. While midurethral slings (MUS) are widely used, concerns over complications such as mesh exposure/erosion and chronic pain have driven interest in regenerative medicine alternatives. This review explores emerging strategies, including stem cell therapies, platelet-rich plasma injections, decellularized extracellular matrix scaffolds, injectable hydrogels, and bioengineered slings. These approaches aim to restore continence by promoting tissue regeneration, improving biocompatibility, and reducing adverse reactions. We evaluate their mechanisms, reported outcomes, and current stage of development, supported by in vitro and in vivo model data. Although promising, these technologies face challenges related to cell viability, scaffold integration, and clinical translation. Continued interdisciplinary research is essential to optimize these therapies and bring safer, more effective solutions to patients. Regenerative strategies may ultimately redefine the future of SUI treatment by offering biologically integrated, long-lasting alternatives to synthetic slings. To date, no tissue-engineered or regenerative biomimetic sling has received regulatory approval for routine clinical use in the management of stress urinary incontinence. Full article

Electrospun poly(ε-caprolactone) (PCL) membranes incorporating Triticum vulgare extract (TVE) were developed as biomimetic scaffolds for periodontal regeneration. Using a ternary solvent system, two experimental formulations (µF-P10 and µF-P10T1) were fabricated and compared against a commercial dermal matrix. SEM analysis revealed bimodal fiber distributions (0.77–1.74 µm) and a surface porosity of 29.86% for TVE-loaded membranes, significantly higher than that of the commercial control (25.26%). FT-IR confirmed that the PCL chemical integrity was preserved, while mechanical testing showed that extract incorporation reinforced the matrix, increasing the Young’s modulus from 2.90 × 10³ Pa to 3.54 × 10³ Pa. UHPLC–MS identified ferulic acid as the primary bioactive component (90%), with release kinetics following a first-order model (R² = 0.998) over 48 h. Biological assays with human gingival fibroblasts (HGF) confirmed non-cytotoxicity (>70% viability). While both membranes supported healing, the µF-P10 formulation showed superior performance, with 80.2% proliferation and 60.6% wound closure, approaching control levels. These findings demonstrate that PCL-TVE electrospun scaffolds effectively combine favorable morphology and controlled release, offering a promising alternative for subepithelial connective tissue regeneration. Full article

The treatment of skin diseases remains a significant clinical challenge. Cellulose and its derivatives have emerged as research hotspots in skin-related applications due to their excellent biocompatibility, structural modifiability, and biomimetic properties. This review systematically summarizes the diverse construction forms of cellulose-based materials, including films, nanofibrous scaffolds, hydrogels, and aerogels, with a focus on smart responsive systems tailored to various microenvironmental conditions. Their application progresses in acute/chronic wound healing, bacterial infections, burns, scar prevention, immunomodulation, and smart wearable monitoring are highlighted. The underlying mechanisms involving anti-infection, pro-regeneration, microenvironment modulation, and sensing are analyzed, aiming to provide insights for further exploration of cellulose-based materials in skin disease therapy and even smart wearable devices. Full article

The fabrication of decellularized small intestinal submucosa (dSIS) requires a precise balance between effective cellular removal and the preservation of structural integrity. In this study, we compared four published dSIS protocols representing detergent-based, chaotropic-salt-based, and sequential ionic/alkaline–acidic strategies. Their performance was evaluated based on residual DNA, collagen preservation, surface ultrastructure, and mechanical properties. The best decellularization protocol demonstrated the lowest residual DNA levels, together with better collagen retention, scaffold architecture, and mechanical performance than the other methods tested. The selected decellularized scaffold was used in a murine acute wound model and showed good biocompatibility and integration with the surrounding tissue at 10 days after implantation. However, further extensive testing in murine models is essential before future scaling. Finally, this comparative study provides a practical framework for selecting dSIS preparation methods for skin repair applications. Full article

Diabetic wounds are a common and severe complication of diabetes mellitus, characterized by delayed healing due to persistent inflammation, impaired angiogenesis, and cellular dysfunction. Conventional therapeutic approaches remain limited in efficacy. In recent years, exosomes have attracted considerable attention in wound healing and regenerative medicine because of their crucial role in intercellular communication and tissue repair. However, rapid clearance of exosomes in vivo greatly limits their therapeutic efficacy. To address this critical limitation, we engineered a decellularized extracellular matrix (dECM)-based hydrogel system functionalized with exosomes derived from skin-derived precursor cells (SKPs). This biomimetic scaffold was designed to serve as a local exosome-delivery platform at the wound site, with the aim of improving exosome utilization and augmenting their regenerative effects. Comprehensive in vitro characterization demonstrated that the exosome-loaded composite hydrogels exhibited robust pro-angiogenic activity, as evidenced by enhanced endothelial cell proliferation, migration, and tube formation. Moreover, the hydrogels displayed significant antibacterial effects against wound-relevant pathogens and potent reactive oxygen species (ROS)-scavenging capacity, thereby mitigating oxidative damage. Notably, the composite hydrogels also promoted the phenotypic polarization of macrophages toward the pro-regenerative M2 phenotype. In parallel, in vivo studies using a streptozotocin-induced diabetic rat wound model confirmed that treatment with the composite hydrogels significantly accelerated wound closure rates compared to control groups. Histological and immunohistochemical analyses revealed enhanced angiogenesis, as evidenced by increased CD31-positive microvessel density, as well as improved collagen deposition, re-epithelialization, and an attenuated local inflammatory microenvironment characterized by reduced pro-inflammatory cytokine expression and elevated M2 macrophage infiltration. Collectively, the SKPs exosome-loaded dECM based composite hydrogels developed in this study represent a potential therapeutic strategy for the treatment of diabetic wounds. Full article

Bone marrow(BM) is the primary site of hematopoiesis, supporting the self-renewal and differentiation of hematopoietic stem cells (HSCs). Its function depends on a highly complex microenvironment composed of stromal cells, vascular networks, extracellular matrix components, and dynamic biophysical signals. Traditional two-dimensional culture systems and animal models fail to adequately recapitulate the spatial architecture and dynamic regulatory processes of the human bone marrow niche, thereby limiting in-depth investigations into hematopoietic regulatory mechanisms, disease pathogenesis, and drug-induced bone marrow toxicity. In recent years, advances in microphysiological systems (MPS) have provided novel engineering approaches for the in vitro reconstruction of the bone marrow microenvironment. This review systematically summarizes current construction strategies for bone marrow MPS, including three-dimensional self-organized bone marrow organoids and microfluidic bone marrow-on-a-chip platforms. Particular attention is given to the roles of key cellular components, biomaterial scaffolds, vascularized architectures, and dynamic perfusion systems in biomimetic bone marrow engineering. In addition, we discuss strategies for constructing more complex models, such as vascular niches, vascularized bone tissue constructs, and bone metastasis models. Bone marrow MPS more faithfully recapitulate the hematopoietic microenvironment and provide a physiologically relevant in vitro platform for hematopoietic research, disease modeling, and drug evaluation, thereby supporting future advances in precision and regenerative medicine. Full article

Background: Osteosarcoma (OS) is an aggressive bone tumor. The lack of physiologically relevant three-dimensional models that recapitulate the native tumor microenvironment hampers drug development and mechanistic studies. The study aimed to develop bone-mimetic microspheres for the construction of an OS model. Materials and Methods: We employed droplet microfluidics to fabricate bone-mimetic microspheres (named MSHA) from a composite of gelatin methacryloyl, polyethylene glycol diacrylate, and nano-hydroxyapatite (nHA). MNNG/HOS cells were cultured on MSHA microspheres and subsequently evaluated for their bioactivity and capabilities of stemness, migration, and invasion. Results: The microfluidic platform enabled efficient and scalable production of highly uniform MSHA microspheres with controlled sizes. MNNG/HOS cells cultured on MSHA maintained high viability and spontaneously formed compact tumor spheroids after 7 days. Compared with two-dimensional cultures, cells cultured on these microsphere-based platforms exhibited enhanced migration and invasion capacities, along with increased expression of relevant biomarkers. RNA sequencing further revealed the activation of cancer-related pathways. Notably, the incorporation of nHA into microspheres amplified these malignant phenotypes, potentially through the activation of ECM–receptor interaction and calcium signaling pathways. Conclusions: The microfluidics-fabricated MSHA microspheres, as biomimetic three-dimensional culture scaffolds, offer a promising platform for applications in mechanistic studies of osteosarcoma progression and drug screening. Full article

Repairing maxillofacial bone defects remains a major clinical challenge due to inadequate vascularisation and poor integration with host tissue. While bioactive scaffolds have shown promise in supporting osteogenesis and angiogenesis, achieving robust and synchronised dual regenerative outcomes is still elusive. This study presents a multifunctional, cell-free magnetic hydrogel platform designed to biomimetically coordinate osteogenic and angiogenic processes for effective maxillofacial bone regeneration. The composite poly(vinyl alcohol)-vaterite (PVA-Vat) hydrogel scaffold incorporates tuneable magnetic nanoparticles (MNPs) composed of single-domain superparamagnetic iron oxide (Fe₃O₄). By harnessing magneto-mechanical cues to orchestrate bilateral communication between human bone mesenchymal stem cells and endothelial cells, this platform provides a deeper mechanistic understanding of coupled tissue regeneration and delivers superior dual-regenerative performance for maxillofacial bone repair. Under magnetic stimulation, a coculture system demonstrated strong osteogenesis-angiogenesis coupling mediated by reciprocal VEGFA-BMP2 signalling. This reciprocal crosstalk was evidenced by a synergistic amplification of VEGFA and BMP2 expression in coculture compared to monocultures, where MNP-stimulated osteoprogenitors secreted VEGFA to drive endothelial capillary-like network formation, while endothelial cells reciprocally enhanced endogenous BMP2 levels to accelerate osteoblastic mineralisation. These findings establish MNP-integrated hydrogels as a cell-free, multifunctional platform capable of synchronising dual regenerative pathways, offering a biomimetic strategy to overcome vascularisation and integration barriers in maxillofacial bone repair. Full article

Segmental bone defects are large, non-healing injuries characterized by insufficient structural support and limited bioactivity, posing a significant clinical challenge. In this study, we developed biomimetic chitosan/polyvinyl alcohol–glycerol (CS/PG) scaffolds inspired by porcupine quills, which were fabricated via fused deposition modeling and unidirectional freeze casting. The as-prepared scaffold featured a dense outer layer of polyvinyl alcohol–glycerol (PG) with high compressive strength (24.21 ± 0.11 MPa at 25% strain) and an oriented inner foam of chitosan (CS). The CS foam was further incorporated with poly (3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS, denoted as PP) and amorphous zinc phosphate (AZP) to form PP-AZP-CS/PG, aimed at enhancing neural conductivity and stimulating blood vessel formation, respectively. The in vitro results indicated that the biomimetic scaffolds exhibited excellent biocompatibility while significantly enhancing angiogenesis and osteogenesis capabilities. In a rabbit radial segmental defect model, PP-AZP-CS/PG achieved robust bone regeneration, attaining a bone volume/total volume of approximately 26.22% after implantation for 8 weeks. Overall, this biomimetic scaffold demonstrated that integrating hierarchical design with additional bioactive components enhanced mechanical support while promoting new bone regeneration, addressing critical challenges in segmental bone defect repair. Full article