Search Results (535)

Tissue engineering is a growing field with multidisciplinary players in cell biology, engineering, and medicine, aiming to maintain, restore, or enhance functions of tissues and organs. The extracellular matrix (ECM) plays fundamental roles in tissue development, maintenance, and repair, providing not only structural support, but also critical biochemical and biomechanical cues that regulate cell behavior and signaling. Although its specific composition varies across different tissue types and developmental stages, matrix molecules influence various cell functional properties in every tissue. Given the importance of ECM in morphogenesis, tissue homeostasis, and regeneration, ECM-based bioscaffolds, developed through tissue engineering approaches, have emerged as pivotal tools for recreating the native cellular microenvironment. The aim of this study is to present the main categories of these scaffolds (i.e., natural, synthetic, and hybrid), major fabrication techniques (i.e., tissue decellularization and multidimensional bioprinting), while highlighting the advantages and disadvantages of each category, focusing on biological activity and mechanical performance. Scaffold properties, such as mechanical strength, elasticity, biocompatibility, and biodegradability are essential to their function and integration into host tissues. Applications of ECM-based bioscaffolds span a range of engineering and regenerative strategies, including cartilage, bone, cardiac tissue engineering, and skin wound healing. Despite promising advances, challenges remain in standardization, scalability, and immune response modulation, with future directions directed towards improving ECM-mimetic platforms. Full article

Cartilage damage, particularly in the knee joint, presents a significant challenge in regenerative medicine due to its limited capacity for self-repair. Conventional treatments like microfracture surgery, autologous chondrocyte implantation (ACI), and osteochondral allografts often fall short, particularly in cases of larger defects or degenerative conditions. This has led to a growing interest in tissue engineering approaches that utilize biomaterial scaffolds to support cartilage regeneration. Among the many materials explored, chitosan—a naturally derived polysaccharide—has gained attention for its biocompatibility, biodegradability, and structural resemblance to the extracellular matrix (ECM) of cartilage. Recent advances in scaffold design have focused on modifying chitosan to improve its mechanical properties and enhance its biological performance. These modifications include chemical crosslinking, the incorporation of bioactive molecules, and the development of composite formulations. Such enhancements have allowed chitosan-based scaffolds to better support mesenchymal stem cell (MSC) differentiation into chondrocytes, paving the way for improved regenerative strategies. This review explores the latest progress in chitosan scaffold fabrication, preclinical findings, and the transition toward clinical applications. It also discusses the challenges that need to be addressed, such as mechanical stability, degradation rates, and the successful translation of research into viable therapeutic solutions. Full article

Mesenchymal stem cells (MSCs) represent a promising cell source for cartilage tissue engineering due to their chondrogenic potential. However, current differentiation protocols result in limited efficiency. This study assessed the combined effects of transforming growth factor-beta 3 (TGF-β3) and fibroblast growth factor-2 (FGF-2) on the morphology, proliferation, chondrogenic differentiation, chondrogenic gene expression, and cytokine profile of ovine bone marrow-derived MSCs (BM-MSCs). BM-MSCs were cultured under four conditions: control (αMEM) or αMEM supplemented with FGF-2, TGF-β3, or TGF-β3 + FGF-2. Morphological and proliferation analyses, Alcian blue staining in 2D and 3D, and real-time PCR for early (Chad, Comp, and Sox 5) and late (Agg, Col IX, Sox 9, and Fmod) chondrogenic markers were performed. Cytokine secretion profiles were analyzed using multiplex assay. TGF-β3 induced morphological changes indicative of early chondrogenesis, while FGF-2 enhanced proliferation. The combination of both cytokines led to a synergistic increase in cell proliferation, early and late chondrogenic gene expression, and glycosaminoglycans (GAG) deposition. Cytokine analysis revealed that TGF-β3 enhanced the immunomodulatory and angiogenic profile of BM-MSCs, whereas co-treatment with FGF-2 yielded a balanced and potentially regenerative secretome. Dual stimulation with TGF-β3 and FGF-2 significantly improves the chondrogenic differentiation of ovine BM-MSCs by enhancing both molecular and functional markers of cartilage formation. Full article

Cartilage injuries, due to their limited regenerative capacity, often result in chronic pain and functional impairment. These injuries are difficult to manage with conventional surgical repair techniques; therefore, alternative treatments are necessary. Gelatin methacrylate (GelMA) has emerged as a promising biomaterial for cartilage tissue engineering due to its biocompatibility, tunable mechanical properties, and ability to be used in advanced applications like 3D bioprinting. This review examines the synthesis, properties, and limitations of GelMA in cartilage repair, focusing on its applications in 3D bioprinting for the creation of patient-specific cartilage constructs. It also highlights preclinical studies exploring the potential of GelMA-based scaffolds in various animal models. Despite its advantages, challenges remain, such as the mechanical limitations of GelMA and its degradation rate in dynamic environments. Hybrid scaffolds, in situ bioprinting, and personalized bioinks offer solutions to these issues. Ultimately, long-term clinical trials are needed to assess the durability and efficacy of GelMA-based scaffolds in human applications. Future research is aimed at overcoming these challenges, improving the mechanical strength of GelMA scaffolds, and enhancing their clinical translation for cartilage repair. Full article

Articular cartilage (AC) plays an important role in the biomechanics of synovial joints. Its task is to enable smooth movement and transfer of mechanical loads with minimised friction. AC is characterised by unique mechanical properties resulting from its complex structure, in which the dominant components are type II collagen, proteoglycans and water. Healthy articular cartilage shows elasticity in compression, viscoelastic properties, and the ability to relax stresses under the influence of cyclic loads. In response to different loading modes, it shows anisotropic and non-uniform behaviour, which translates into its cushioning and protective function for the subchondral bone. Significant changes occur in the structure and mechanical properties of cartilage with age as a result of mechanical overload or degenerative diseases, such as osteoarthritis. This results in a deterioration of the cushioning and mechanical function, which leads to progressive degradation of joint tissues. Understanding the mechanical properties of AC is crucial for developing effective diagnostic methods. Analysis of changes in mechanical properties contributes to the early detection of pathological changes. The aim of this paper is to review the current state of knowledge regarding the structure and biomechanical properties of articular cartilage, and to analyse conventional and alternative diagnostic methods in the context of their suitability for assessing the state of AC, particularly in the early stages of degenerative processes. Full article

Articular cartilage is an avascular and aneural connective tissue that is frequently damaged due to trauma or degenerative joint diseases, often resulting in arthritis. Its limited intrinsic capacity for self-renewal poses a significant challenge to effective repair. Hence, the development of regenerative strategies is essential to enhance the poor intrinsic healing of cartilage tissue. Photobiomodulation (PBM) has gained increasing attention as a noninvasive, drug-free, and safe approach. PBM exerts photobiological effects that promote cellular responses and reduce inflammatory conditions, all of which are beneficial for cartilage repair. Nonetheless, the efficacy of PBM varies depending on treatment parameters and treated targets. This review first summarizes PBM parameter-dependent outcomes in cartilage regeneration studies. Reported data indicate frequent use of red lasers (600–660 nm, 0–10 J/cm²), GaAIAs lasers (800–880 nm, 10–50 J/cm²), and Nd:YAG lasers (1064 nm, up to 200 J/cm²) in in vitro, in vivo, and clinical studies. Moreover, PBM in conjunction with cartilage tissue engineering (CTE) has shown synergistic effects, enhancing scaffold-based repair outcomes. This review additionally explores PBM applications within CTE frameworks. The summarized findings aim to inform researchers and physicians by outlining optimized PBM strategies and highlighting PBM’s strong potential in promoting cartilage regeneration, both independently and in combination with CTE. Full article

Cartilage tissue engineering (CTE) is an advancing field focused on developing biomimetic scaffolds to overcome cartilage’s inherently limited self-repair capacity. Smart hydrogels (SHs) have gained prominence among the various scaffold materials due to their ability to modulate cellular behavior through tunable mechanical and biochemical properties. These hydrogels respond dynamically to external stimuli, offering precise control over biological processes and facilitating targeted tissue regeneration. Recent advances in fabrication technologies have enabled the design of SHs with sophisticated architecture, improved mechanical strength, and enhanced biointegration. Key features such as injectability, controlled biodegradability, and stimulus-dependent release of biomolecules make them particularly suitable for regenerative applications. The incorporation of nanoparticles further improves mechanical performance and delivery capability. In addition, shape memory and self-healing properties contribute to the scaffolds’ resilience and adaptability in dynamic physiological environments. An emerging innovation in this area is integrating artificial intelligence (AI) and omics-based approaches that enable high-resolution profiling of cellular responses to engineered hydrogels. These data-driven tools support the rational design and optimization of hydrogel systems and allow the development of more effective and personalized scaffolds. The convergence of smart hydrogel technologies with omics insights represents a transformative step in regenerative medicine and offers promising strategies for restoring cartilage function. Full article

Current hydrogels used for cartilage tissue engineering often lack the mechanical strength and structural integrity required to mimic native human cartilage. This study addresses this limitation by developing reinforced hydrogels based on a ternary polymer blend of poly(vinyl) alcohol (PVA), gelatin (GL), and chitosan (CH), with gentamicin sulfate (GS) as an antimicrobial agent and a crosslinker. The hydrogels were produced using two crosslinking methods, the freeze/thaw and heated cycles, and reinforced with forcespun polycaprolactone (PCL) nanofiber to improve mechanical performance. Chemical characterization revealed that GS forms weak hydrogen bonds with the ternary polymers, leading to esterification with PVA, and covalent bonds are formed as the result of the free amino group (-NH₂) of chitosan that reacts with the carboxylic acid group (-COOH) of gelatin. SEM images help us to see how the hydrogels are reinforced with polycaprolactone (PCL) fibers produced via force spinning technology, while mechanical properties were evaluated via uniaxial tensile and compressive tests. Water retention measurements were performed to examine the crosslinking process’s influence on the hydrogel’s water retention, while the hydrogel surface roughness was obtained via confocal microscopy images. A constitutive model based on non-Gaussian strain energy density was introduced to predict experimental mechanical behavior data of the hydrogel, considering a non-monotonous softening function. Loading and unloading tests demonstrated that GS enhanced crosslinking without compromising water retention or biocompatibility because of the reaction between the free amino group of CH and the carboxylic group of gelatin. The PCL-reinforced PVA/GL/CH hydrogel shows strong potential for cartilage repair and tissue engineering applications. Full article

Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) is a naturally occurring biopolymer belonging to the polyhydroxyalkanoate (PHA) family. Due to its excellent properties (biocompatible, biodegradable, and non-toxic), this biopolymer is presented as a very suitable option for use in regenerative therapy as a drug delivery system (DDS). The protein encapsulated in this study is transforming growth factor β3 (TGF-β3), which plays a key role in the chondrogenic differentiation of mesenchymal stem cells (MSCs). The main objective of this work is to evaluate the efficacy of PHBV nanoparticles (NPs) produced from a dairy by-product (whey) as a DDS of TGF-β3 for cartilage regeneration and extracellular matrix (ECM) synthesis and to reduce the complications associated with multiple high doses of TGF-β3 in its free form. For this purpose, biopolymer cytotoxicity, factor release, cell viability, cell proliferation, and differentiation were analyzed. The results showed that the biomaterial purified with chloroform and ethanol, either by single or double precipitation, was not toxic to cells. A sustained release profile was observed, reaching its maximum around day 4. The TGF-β3 NPs promoted the differentiation of MSCs into chondrocytes and the formation of ECM. In conclusion, PHBV demonstrated its potential as an optimal material for DDSs in cartilage regenerative therapy, effectively addressing the key challenge of the need for a single delivery method to reduce complications associated with multiple high doses of TGF-β3. Full article

This study developed composite hydrogel scaffolds from chitosan (CS), silk fibroin (SF), and Aloe vera (AV) gel extract for cartilage tissue engineering. SF extracted from Nang-Laai silkworm cocoons showed high protein content (86.8%), while AV extract contained characteristic polysaccharides. Scaffolds with varying CS/SF/AV ratios were fabricated and evaluated for physicochemical and biological properties. Among all formulations, CS40/SF/AV (3.00%wt CS, 2.70%wt SF, 0.075%wt AV) exhibited superior porosity (72.23 ± 4.85%), pore size (79.57 ± 3.68 μm), and compressive strength, both in dry (6.67 ± 1.44 MPa) and wet states. It also showed controlled swelling (270%) and a stable degradation profile (55–57% over 21 days). FTIR and XRD confirmed successful component integration and semi-crystalline structure. In vitro, CS40/SF/AV supported chondrocyte adhesion, proliferation, and morphology retention over 28 days. Fluorescence imaging showed uniform cell distribution across the scaffold. These results highlight the CS40/SF/AV scaffold as a promising, biocompatible platform with optimal mechanical and structural properties for cartilage regeneration, offering potential for further in vivo applications. Full article

Background and Objectives: Demineralized bone matrix (DBM) is a widely used bone graft substitute due to its osteoconductive and osteoinductive properties. However, its efficacy varies due to differences in donor, processing, and storage conditions. Synthetic alternatives, such as iFactor^®, combine non-organic bone mineral and a small peptide (P-15) to enhance the cellular attachment and osteogenesis. To compare the osteogenic potential and bone matrix maturity of iFactor^® and a commercial DBM scaffold through calcium nodule formation and Fourier transform infrared spectroscopy (FTIR) analysis. Materials and Methods: Human mesenchymal stem cells (hMSCs) were cultured and exposed to iFactor^® or DBM in paracrine culture conditions for 21 days. Calcium nodule formation was assessed using alizarin red staining and quantified spectrophotometrically. The FTIR analysis of hMSCs exposed to the scaffolds for three months evaluated the biomolecular composition and bone matrix maturity. Results: Calcium nodules formed in both groups but in smaller quantities than in the positive control (p < 0.05). The biomolecular components of the DBM were similar to healthy bone (p > 0.05) than those of the iFactor^® group (p < 0.005). A different rate of bone regeneration was observed through the formation of a greater number of calcium nodule aggregates identified in the extracellular matrix of mesenchymal stem cell cultures exposed to iFactor^® compared to those cultures enriched with DBM. Conclusions: Both experimental matrices demonstrated similar osteogenic potential at the 3-month follow-up. Although DBM has a closer biomolecular composition and carbonate substitution compared to healthy bone, iFactor^® showed faster matrix maturity expressed through the formation of a greater number of calcium nodule aggregates and higher hMSCs proliferation. Full article

Polymeric scaffolds are promising in tissue engineering due to their structural similarity to extracellular matrix components. This study aimed to design freeze-dried hydrogels based on chitosan (CHT) and hyaluronic acid (HA). Chitosan-based gels were crosslinked with oxidized maltodextrin (MDo) before the freeze-drying step, resulting in spongy porous scaffolds. Based on the state-of-the-art, our hypothesis was that crosslinking would increase scaffold stiffness and delay the degradation of the CHT:HA resorbable scaffolds swelled in a hydrated physiological environment. The physicochemical and mechanical properties of crosslinked CHT- and CHT:HA-based scaffolds were analyzed. Hygroscopic and swelling behavior were assessed using dynamic vapor sorption analysis and batch studies. Degradation was evaluated under different conditions, including in phosphate-buffered saline (PBS), PBS with lysozyme, and lactic acid solutions, to investigate scaffold resistance against enzymatic and acidic degradation. The porosity of the spongy materials was characterized using scanning electron microscopy, while dynamic mechanical analysis provided information on the mechanical properties. Crosslinked scaffolds showed reduced swelling, slower degradation rates, and increased stiffness, confirming MDo as an effective crosslinking agent. Scaffolds loaded with ciprofloxacin (CFX) demonstrated their ability to deliver therapeutic agents, as the CFX loading capacity was promoted by CHT–CFX interactions. Microbiologic investigation confirmed the results. Finally, cytotoxicity tests displayed no toxicity. In conclusion, MDo-crosslinked CHT and CHT:HA scaffolds exhibit enhanced stability, functionality, and mechanical performance, making them promising for cartilage tissue engineering. Full article

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by low-grade inflammation, cartilage breakdown, and persistent pain. Despite its prevalence, current therapeutic strategies primarily focus on symptom management rather than modifying disease progression. Monoclonal antibodies and cytokine inhibitors targeting inflammatory pathways, including TNF-α and IL-1, have shown promise but remain limited by inconsistent efficacy and safety concerns. Long-acting biologic therapies—ranging from extended-release formulations, such as monoclonal antibodies and cytokine inhibitors, to gene therapy approaches—have emerged as promising strategies to enhance treatment durability and improve patient outcomes. Extracellular vesicles (EVs) have gained particular attention as a novel delivery platform due to their inherent stability, biocompatibility, and ability to transport therapeutic cargo, including biologics and immunomodulatory agents, directly to joint tissues. This review explores the evolving role of EVs in OA treatment, highlighting their ability to extend drug half-life, improve targeting, and modulate inflammatory responses. Additionally, strategies for EV engineering, including endogenous and exogenous cargo loading, genetic modifications, and biomaterial-based delivery systems, are discussed. Full article

Developing a functional tissue-engineered articular cartilage remains a challenge to improving clinical treatment of cartilage injury and joint-related degenerative disease. The dynamic self-regenerating cartilage (dSRC) approach presented here encourages autologous chondrocytes to generate their own matrix rather than imposing a matrix upon them. dSRC constructs were grown for 12 weeks under hypoxic conditions in reciprocating motion. Biochemical composition was evaluated, specifically water, collagen, and proteoglycan content. Speckle rHEologicAl micRoscopy (SHEAR) was utilized for spatially resolved evaluation of the shear modulus in engineered cartilage. Histological and immunohistochemical analyses of dSRC were also performed. The maturation of the dSRC matrix results in collagen and glycosaminoglycan (GAG) levels around 50% of those in native cartilage. SHEAR images demonstrate an increase in shear modulus of the matrix to ~20% that of native cartilage after 12 weeks. Histological support for excellent collagen and GAG production was evident, and immunohistochemistry showed a high preference for hyaline-like type II collagen in the neomatrix. A decrease in chondrocyte density occurred from an initial hypercellular matrix to that approaching native cartilage by 12 weeks. While this maturation of dSRC in vitro should not be construed as an absolute prediction of in vivo performance, these results are encouraging, representing a potential new cartilage repair and regeneration approach. Full article

Musculoskeletal tissue injuries of the bone, cartilage, ligaments, tendons, and skeletal muscles are among the most common injuries experienced in medicine and become increasingly problematic in cases of significant tissue damage, such as nonunion bone defects and volumetric muscle loss. Current gold standard treatment options for musculoskeletal injuries, although effective, have limited capability to fully restore native tissue structure and function. To overcome this challenge, three-dimensional (3D) printing techniques have emerged as promising therapeutic options for tissue regeneration. Melt electrowriting (MEW), a recently developed advanced 3D printing technique, has gained significant traction in the field of tissue regeneration because of its ability to fabricate complex customizable scaffolds via high-precision microfiber deposition. The tailorability at microscale levels offered by MEW allows for enhanced recapitulation of the tissue microenvironment. Here, we survey the recent contributions of MEW in advancing musculoskeletal tissue engineering. More specifically, we briefly discuss the principles and technical aspects of MEW, provide an overview of current printers on the market, review in-depth the latest biomedical applications in musculoskeletal tissue regeneration, and, lastly, examine the limitations of MEW and offer future perspectives. Full article