Cartilage Tissue Engineering Research Articles

Aquisição de medicamentos no setor público de saúde: revisão de escopo

Cartilage has limited self-repair ability due to its complex structure and chondrocytes' relatively low metabolic activities. Functional repair of articular cartilage defects is a significant challenge for cartilage tissue engineering. Mesenchymal stromal cells (MSC) and platelet-rich fibrin membrane (PRFM) in repairing damaged articular cartilage in rabbit. They were subjected to osteochondral lesion and randomly into five groups: Group A, evaluated immediately after injury; Group B, natural evolution the injury; Group C, MSC; Group D, PRFM and Group E, MSC+ PRFM. Animals in Group A were euthanized after removing the cartilaginous flap, while animals in Groups B, C, D, and E were euthanized 60 days. The regeneration of the lesion was evaluated by analyzing its residual extension, as well as the density of chondrocytes and chondroblasts in the regenerated tissue adjacent to the lesion. Results, the Group E (MSC + PRFM) showed a greater reduction in the lesion size and a greater density of chondrocytes and chondroblasts in the regenerated and adjacent tissue compared to the other groups. Our results indicate that the combination of MSC and PRFM can successfully resurface the defect with cartilage and restore the subchondral bone in the specie studied, being effective in reducing hyaline cartilage defects; however, the combination of MSC and PRFM products might be more or less appropriate for treating different types of tissues and pathologies. The clinical efficacy of PRP remains under debate. Therefore, further research is needed at both the basic science and clinical levels.

Human Septal Cartilage Tissue Engineering: Current Methodologies and Future Directions

Human Septal Cartilage Tissue Engineering: Current Methodologies and Future Directions

Engineered self-regulating macrophages for targeted anti-inflammatory drug delivery

BackgroundRheumatoid arthritis (RA) is a systemic autoimmune disease characterized by increased levels of inflammation that primarily manifests in the joints. Macrophages act as key drivers for the progression of RA, contributing to the perpetuation of chronic inflammation and dysregulation of pro-inflammatory cytokines such as interleukin 1 (IL-1). The goal of this study was to develop a macrophage-based cell therapy for biologic drug delivery in an autoregulated manner.MethodsFor proof-of-concept, we developed “smart” macrophages to mitigate the effects of IL-1 by delivering its inhibitor, IL-1 receptor antagonist (IL-1Ra). Bone marrow-derived macrophages were lentivirally transduced with a synthetic gene circuit that uses an NF-κB inducible promoter upstream of either the Il1rn or firefly luciferase transgenes. Two types of joint like cells were utilized to examine therapeutic protection in vitro, miPSCs derived cartilage and isolated primary mouse synovial fibroblasts while the K/BxN mouse model of RA was utilized to examine in vivo therapeutic protection.ResultsThese engineered macrophages were able to repeatably produce therapeutic levels of IL-1Ra that could successfully mitigate inflammatory activation in co-culture with both tissue-engineered cartilage constructs and synovial fibroblasts. Following injection in vivo, macrophages homed to sites of inflammation and mitigated disease severity in the K/BxN mouse model of RA.ConclusionThese findings demonstrate the successful development of engineered macrophages that possess the ability for controlled, autoregulated production of IL-1 based on inflammatory signaling such as via the NF-κB pathway to mitigate the effects of this cytokine for applications in RA or other inflammatory diseases. This system provides proof of concept for applications in other immune cell types as self-regulating delivery systems for therapeutic applications in a range of diseases.

Comparison study on hyaline cartilage versus fibrocartilage formation in a pig model by using 3D-bioprinted hydrogel and hybrid constructs

Cartilage tissue engineering (CTE) with the help of engineered constructs has shown promise for the regeneration of hyaline cartilage, where fibrocartilage may also be formed due to the biomechanical loading resulting from the host weight and movement. Previous studies have primarily reported on hyaline cartilage formationin vitroand/or in small animals, while leaving the fibrocartilage formation undiscovered. In this paper, we, at the first time, present a comparison study on hyaline cartilage versus fibrocartilage formation in a large animal model of pig by using two constructs (namely hydrogel and hybrid ones) engineered by means of three-dimensional (3D) bioprinting. Both hydrogel and hybrid constructs were printed from the bioink of alginate (2.5%) and ATDC5 cells (chondrogenic cells at a cell density of 5 × 106cells ml-1), with the difference in that in the hybrid construct, there was a polycaprolactone (PCL) strand printed between every two bioink strands, which were strategically designed to shield the force imposed on the cells within the bioink strands. Both hydrogel and hybrid constructs were implanted into the chondral defects created in the articular cartilage of weight-bearing portions of pig stifle joints; the cartilage formation was examined at one- and three-months post-implantation, respectively, by means of Safranin O, Trichrome, immunofluorescent staining, and synchrotron radiation-based (SR) inline phase contrast imaging microcomputed tomography (inline-PCI-CT). Glycosaminoglycan (GAG) and collagen type II (Col II) secretion were used to evaluate the hyaline cartilage formation, while collagen type I (Col I) was used to indicate fibrocartilage given that Col I is low in hyaline cartilage but high in fibrocartilage. Our results revealed that cartilage formation was enhanced over time in both hydrogel and hybrid constructs; particularly, the hydrogel construct exhibited more cartilage formation at both one- and three-months post-implantation, while hybrid constructs tended to have less fibrocartilage formed in a long time period. Also, the result from the inline-PCI-CT revealed that the inline-PCI-CT was able to provide not only the information seen in other histology images, but also high-resolution details of biomaterials and regenerating cartilage. This would represent a significant advance toward the non-invasive assessment of cartilage formation regeneration within large animal models and eventually in human patients.

A drug-loaded nano chitosan/hyaluronic acid hydrogel system as a cartilage tissue engineering scaffold for drug delivery

Cartilage lesions, especially osteoarthritis (OA), usually arise from aging, trauma, or obesity and require medical intervention due to the damaged site's inflammation and the cartilage tissue's poor self-healing capacity. This study aimed to prepare a drug-loaded nanoparticle hydrogel system with anti-inflammatory and chondroprotective effects to treat OA. First, hyaluronic acid (HA) was oxidized to create aldehyde functional groups and then cross-linked with adipic acid dihydrazide (ADH) to form a hydrogel. Next, chitosan nanoparticles (CS NPs) loaded with an anti-inflammatory molecule (fisetin) and or a chondrogenic and chondroprotective agent (kartogenin) were incorporated into the hyaluronan hydrogel to improve the release profile of the drug and increase its retention time in the joint cavity. Incorporating drug-loaded NPs into the hyaluronan hydrogel provided the hydrogel with controlled release features and improved properties. In addition, the real-time PCR (Polymerase chain reaction) results showed that the hyaluronan hydrogel containing both drug-loaded NPs performed better than either constituent alone on an in vitro model of OA. Finally, based on the results of in vitro evaluation, this drug-loaded nanoparticle hydrogel system can be a promising technique for treating OA by rapidly suppressing inflammation and supporting cartilage regeneration and requires further investigation in an animal model of OA. Meanwhile, this study investigated, for the first time, the effect of the simultaneous use of fisetin and kartogenin together with a nano CS/HA hydrogel system to treat OA.

Identification of a Regenerative Protocol for Recellularizing Human Auricular Cartilage Scaffolds.

Utilizing biological scaffolds for cartilage tissue engineering is a promising tool for improving auricular reconstruction. Decellularized auricular scaffolds provide a means of regenerating cartilage for in vivo implantation, but identifying the ideal regenerative mix remains challenging. Human cadaver auricular cartilage was decellularized and recellularized with either auricular chondrocytes alone, auricular chondrocytes with adipose-derived stem cells, or both cells with platelet-rich plasma. Confirmation of decellularization and recellularization was done by hematoxylin and eosin staining. Extracellular matrix preservation and production were determined by Masson's trichrome, Alcian blue, and Verhoeff-van Gieson staining. Collagen II assessments were made using immunohistochemistry. Decellularization of cadaver auricular cartilage was confirmed by the absence of cells, reduction in glycosaminoglycans, and the preservation of collagen and elastin. Recellularization was more efficient when chondrocytes were seeded with adipose-derived stem cells, which was enhanced by adding platelet-rich plasma. Coculture with platelet-rich plasma yielded better total collagen (56% increase) and glycosaminoglycan (47% increase) induction. Moreover, when platelet-rich plasma was added, collagen II induction was significantly increased (42%; P < 0.05). We identified a regenerative protocol that included auricular chondrocytes, adipose-derived stem cells, and platelet-rich plasma, which stimulated chondrogenesis on decellularized auricular cartilage. This finding provides a model to explore cartilage formation and the potential for improving auricular and cartilage-based reconstruction.

The Role of Cartilage Tissue Engineering in Osteoarthritis Treatment: The Bench to Bedside Translation

ABSTRACTCartilage tissue engineering holds huge promise for joint defects and osteoarthritis (OA) conditions which otherwise have limited treatment options due to cartilage's inherent inability to self‐repair. Chemical cues play a pivotal role in regulating chondrocyte behavior and matrix synthesis. Strategies utilizing growth factors, small molecules, and biomaterial‐based delivery systems aim to modulate chondrogenic differentiation, proliferation, and matrix deposition, while recent insights emphasize the significance of mimicking native tissue gradients for optimal regeneration outcomes. Mechanical stimuli profoundly influence chondrocyte phenotype and function, necessitating precise control of the mechanical microenvironment in tissue engineering strategies. Advances in biomaterial design, scaffold fabrication, and bioreactor systems facilitate the tailored modulation of mechanical cues, including substrate stiffness, topography, and dynamic loading regimes. This review showcases the latest advancements in engineering both the chemical and mechanical microenvironment to enhance chondrocyte regeneration. Furthermore, exploring the synergistic effects of combining chemical and mechanical cues underscores the importance of multifaceted approaches in promoting robust chondrocyte regeneration. The review also addresses challenges and future directions in the field, such as achieving spatially organized tissue architecture and integrating patient‐specific factors, to propel advancements in cartilage tissue engineering. We also conducted a comprehensive enlistment for the clinical trials and tissue engineering‐based marketed products for OA therapy.

Construction and performance evaluation of fully biomimetic hyaline cartilage matrix scaffolds for joint defect regeneration

Due to the absence of nerves and blood vessels in articular cartilage, its regeneration and repair present a significant and complex challenge in osteoarthritis treatment. Developing a specialized physical and chemical microenvironment supporting cell growth has been difficult in cartilage grafting, especially when aiming for comprehensive biomimetic solutions. Based on previous research, we have designed a tissue-engineered decellularized living hyaline cartilage graft (dLhCG). The study developed a method to improve the hydrophilicity and stiffness of scaffolds by employing chemical grafting techniques and designed a decellularized hyaline cartilage phenotype matrix scaffold for tissue engineering. Here, we reported a method using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride /N-hydroxysuccinimide (EDC/NHS) to achieve the grafting of chondroitin sulfate (CS) onto dLhCG, ultimately producing a tissue-engineered hyaline cartilage graft with the CS (dLhCG/CS). Young's modulus measurements revealed that the cross-linked scaffolds exhibited enhanced mechanical properties. We implanted the cross-linked dLhCG/CS scaffolds into the trochlear region of rat joints and evaluated their functionality through histological analysis and biomechanical tests. After 12 weeks, the dLhCG/CS scaffolds demonstrated excellent bioinductive activity comparable to dLhCG. The regenerated tissue effectively maintained a hyaline cartilage phenotype and exhibited similar mechanical properties, playing a crucial role in cartilage regeneration.

Antioxidant hydrogels for the treatment of osteoarthritis: mechanisms and recent advances

Articular cartilage has limited self-healing ability, resulting in injuries often evolving into osteoarthritis (OA), which poses a significant challenge in the medical field. Although some treatments exist to reduce pain and damage, there is a lack of effective means to promote cartilage regeneration. Reactive Oxygen Species (ROS) have been found to increase significantly in the OA micro-environment. They play a key role in biological systems by participating in cell signaling and maintaining cellular homeostasis. Abnormal ROS expression, caused by internal and external stimuli and tissue damage, leads to elevated levels of oxidative stress, inflammatory responses, cell damage, and impaired tissue repair. To prevent excessive ROS accumulation at injury sites, biological materials can be engineered to respond to the damaged microenvironment, release active components in an orderly manner, regulate ROS levels, reduce oxidative stress, and promote tissue regeneration. Hydrogels have garnered significant attention due to their excellent biocompatibility, tunable physicochemical properties, and drug delivery capabilities. Numerous antioxidant hydrogels have been developed and proven effective in alleviating oxidative stress. This paper discusses a comprehensive treatment strategy that combines antioxidant hydrogels with existing treatments for OA and explores the potential applications of antioxidant hydrogels in cartilage tissue engineering.

ALB–PRF facilitates chondrogenesis by promoting chondrocytes migration, proliferation and differentiation

Cartilage injury is common in orthopedics and cartilage tissue engineering provides a therapeutic direction for cartilage regeneration. Albumin (ALB)–platelet-rich fibrin (PRF) is speculated to be an ideal natural scaffold material for cartilage tissue engineering theoretically as a product derived from human venous blood. Through in vitro and in vivo experiments, it was demonstrated that ALB–PRF displayed porous structure and slowly released growth factors (TGF-β1, PDGF-AA, PDGF-AB, PDGF-BB, EGF, IGF-1 and VEGF), ALB–PRF conditioned media promoted proliferation, migration, adhesion, phenotype maintenance and extracellular matrix secretion of rabbit chondrocytes. Moreover, ALB–PRF facilitated chondrogenesis in vivo, the regenerative cartilage formed by ALB–PRF/chondrocytes was histologically similar to that of natural knee joint cartilage, the regenerative cartilage expressed cartilage differentiation marker (SOX9, ACAN and COL II), and proliferation marker PCNA and secreted abundant glycosaminoglycans (GAGs) in extracellular matrix. In conclusion, ALB–PRF promoted the migration, proliferation and phenotype maintenance of chondrocytes in vitro. Its loose, porous structure and rich growth factors contained enhanced cell adhesion and growing into the materials. ALB–PRF facilitated chondrogenesis of chondrocytes in vivo.

A single-cell 3D dynamic volume control system for chondrocytes.

In articular cartilage, zone-specific cellular morphology is a typical characteristic of cartilage tissue, which is related with chondrocyte function, inflammation and osteoarthritis (OA). Chondrocyte hypertrophic phenotype is a criticle physiological process which indicates a hallmark of chondrocyte terminal differentiation and bone formation. Thus, developing a in vitro cell culture system for dynamic regulation of single chondrocyte volume at a three-dimensional (3D) level is particularly necessary for understanding how physical cues of matrix microenvironment regulate chondrocyte fate and the degeneration of articular cartilage. Here, based on the soft lithography techniques, we have constructed well-defined single-cell 3D dynamic volume control system to recapitulate the physiological matrix microenvironment of single chondrocyte niche. The results of finite element analysis indicated that the stress and strain distribution in the cell culture region is homogeneous during the stretching process. Additionally, 3D dynamic volume expansion and compression of single cells in physiological or hyperphysiological can be realized in this cell culture system. Our device for single-cell 3D dynamic culture provides a microphysiological culture system for chondrocytes to explore the mechanisms of cartilage hypertrophy, as well as develops a new paradigm for functional cartilage tissue engineering and regenerative medicine.

Cartilage Tissue Engineering in Multilayer Tissue Regeneration.

The functional and structural integrity of the tissue/organ can be compromised in multilayer reconstructive applications involving cartilage tissue. Therefore, multilayer structures are needed for cartilage applications. In this review, we have examined multilayer scaffolds for use in the treatment of damage to organs such as the trachea, joint, nose, and ear, including the multilayer cartilage structure, but we have generally seen that they have potential applications in trachea and joint regeneration. In conclusion, when the existing studies are examined, the results are promising for the trachea and joint connections, but are still limited for the nasal and ear. It may have promising implications in the future in terms of reducing the invasiveness of existing grafting techniques used in the reconstruction of tissues with multilayered layers.

Injectable Janus Base Nanomatrix (JBNm) in Maintaining Long-Term Homeostasis of Regenerated Cartilage for Tissue Chip Applications.

Engineered cartilage tissues have wide applications in in vivo cartilage repair as well as in vitro models, such as cartilage-on-a-chip or cartilage tissue chips. Currently, most cartilage tissue engineering approaches focus on promoting chondrogenesis of stem cells to produce regenerated cartilage. However, this regenerated cartilage can dedifferentiate into fibrotic tissue or further differentiate into hypertrophic or calcified cartilage. One of the most challenging objectives in cartilage tissue engineering is to maintain long-term cartilage homeostasis. Since the microenvironment of engineered cartilage tissue is crucial for stem cell adhesion, proliferation, differentiation, and function, we aim to develop a novel scaffold that can maintain the long-term homeostasis of regenerated cartilage. Therefore, we developed a library of Janus base nanomatrices (JBNms), composed of DNA-inspired Janus nanotubes (JBNts) as well as cartilage extracellular matrix (ECM) proteins. The JBNms were developed to selectively promote chondro-lineage cell functions while inhibiting bone and endothelial cell growth. More importantly, the JBNm can effectively promote chondrogenesis while inhibiting hypertrophy, osteogenesis, angiogenesis, and dedifferentiation. Additionally, the JBNm is injectable, forming a solid scaffold suitable for producing and maintaining regenerated cartilage tissue in microfluidic chips, making it ideal for tissue chip applications. In this study, we successfully created cartilage tissue chips using JBNms. These chips can model cartilage tissue even after long-term culture and can also mimic arthritis progression, making them useful for drug screening. Thus, we have developed a novel nanomaterial approach for improved cartilage tissue engineering and cartilage tissue chip applications.

Advancing Cartilage Tissue Engineering: A Review of 3D Bioprinting Approaches and Bioink Properties.

Articular cartilage is crucial in human physiology, and its degeneration poses a significant public health challenge. While recent advancements in 3D bioprinting and tissue engineering show promise for cartilage regeneration, there remains a gap between research findings and clinical application. This review critically examines the mechanical and biological properties of hyaline cartilage, along with current 3D manufacturing methods and analysis techniques. Moreover, we provide a quantitative synthesis of bioink properties used in cartilage tissue engineering. After screening 181 initial works, 33 studies using extrusion bioprinting were analyzed and synthesized, presenting results that indicate the main materials, cells, and methods utilized for mechanical and biological evaluation. Altogether, this review motivates the standardization of mechanical analyses and biomaterial assessments of 3D bioprinted constructs to clarify their chondrogenic potential.

Autoinduction-Based Quantification of In Situ TGF-β Activity in Native and Engineered Cartilage.

Transforming growth factor beta (TGF-β) is a potent growth factor that regulates the homeostasis of native cartilage and is administered as an anabolic supplement for engineered cartilage growth. The quantification of TGF-β activity in live tissues in situ remains a significant challenge, as conventional activity assessments (e.g., Western blotting of intracellular signaling molecules or reporter cell assays) are unable to measure absolute levels of TGF-β activity in three-dimensional tissues. In this study, we develop a quantification platform established on TGF-β's autoinduction response, whereby active TGF-β (aTGF-β) signaling in cells induces their biosynthesis and secretion of new TGF-β in its latent form (LTGF-β). As such, cell-secreted LTGF-β can serve as a robust, non-destructive, label-free biomarker for quantifying in situ activity of TGF-β in live cartilage tissues. Here, we detect LTGF-β1 secretion levels for bovine native tissue explants and engineered tissue constructs treated with varying doses of media-supplemented aTGF-β3 using an isoform-specific ELISA. We demonstrate that: 1) LTGF-β secretion levels increase proportionally to aTGF-β exposure, reaching 7.4- and 6.6-fold increases in native and engineered cartilage, respectively; 2) synthesized LTGF-β exhibits low retention in both native and engineered cartilage tissue; and 3) secreted LTGF-β is stable in conditioned media for 2 weeks, thus enabling a reliable biological standard curve between LTGF-β secretion and exposed TGF-β activity. Accordingly, we perform quantifications of TGF-β activity in bovine native cartilage, demonstrating up to 0.59 ng/mL in response to physiological dynamic loading. We further quantify the in situ TGF-β activity in aTGF-β-conjugated scaffolds for engineered tissue, which exhibits 1.81 ng/mL of TGF-β activity as a result of a nominal 3 μg/mL loading dose. Overall, cell-secreted LTGF-β can serve as a robust biomarker to quantify in situ activity of TGF-β in live cartilage tissue and can be potentially applied for a wide range of applications, including multiple tissue types and tissue engineering platforms with different cell populations and scaffolds.

Cell Mediated Reactions Create TGF-β Delivery Limitations in Engineered Cartilage

During native cartilage development, endogenous TGF-β activity is tightly regulated by cell-mediated chemical reactions in the extracellular milieu (e.g., matrix and receptor binding), providing spatiotemporal control in a manner that is localized and short acting. These regulatory paradigms appear to be at odds with TGF-β delivery needs in tissue engineering (TE) where administered TGF-β is required to transport long distances or reside in tissues for extended durations. In this study, we perform a novel examination of the influence of cell-mediated reactions on the spatiotemporal distribution of administered TGF-β in cartilage TE applications. Reaction rates of TGF-β binding to cell-deposited ECM and TGF-β internalization by cell receptors are experimentally characterized in bovine chondrocyte-seeded tissue constructs. TGF-β binding to the construct ECM exhibits non-linear Brunauer–Emmett–Teller (BET) adsorption behavior, indicating that as many as seven TGF-β molecules can aggregate at a binding site. Cell-mediated TGF-β internalization rates exhibit a biphasic trend, following a Michaelis-Menten relation (Vmax=2.4 molecules cell-1 s-1, Km=1.7 ng mL-1) at low ligand doses (≤130ng/mL), but exhibit an unanticipated non-saturating power trend at higher doses (≥130ng/mL). Computational models are developed to illustrate the influence of these reactions on TGF-β spatiotemporal delivery profiles for conventional TGF-β administration platforms. For TGF-β delivery via supplementation in culture medium, these reactions give rise to pronounced steady state TGF-β spatial gradients; TGF-β concentration decays by ∼90% at a depth of only 500 μm from the media-exposed surface. For TGF-β delivery via heparin-conjugated affinity scaffolds, cell mediated internalization reactions significantly reduce the TGF-β scaffold retention time (160 to 360-fold reduction) relative to acellular heparin scaffolds. This work establishes the significant limitations that cell-mediated chemical reactions engender for TGF-β delivery and highlights the need for novel delivery platforms that account for these reactions to achieve optimal TGF-β exposure profiles. Statement of SignificanceDuring native cartilage development, endogenous TGF-β activity is tightly regulated by cell-mediated chemical reactions in the extracellular milieu (e.g., matrix and receptor binding), providing spatiotemporal control in a manner that is localized and short acting. However, the effect of these reactions on the delivery of exogenous TGF-β to engineered cartilage tissues remains not well understood. In this study, we demonstrate that cell-mediated reactions significantly restrict the delivery of TGF-β to cells in engineered cartilage tissue constructs. For delivery via media supplementation, reactions significantly limit TGF-β penetration into constructs. For delivery via scaffold loading, reactions significantly limit TGF-β residence time in constructs. Overall, these results illustrate the impact of cell-mediated chemical reaction on TGF-β delivery profiles and support the importance of accounting for these reactions when designing TGF-β delivery platforms for promoting cartilage regeneration.

Mechanical properties and biocompatibility characterization of 3D printed collagen type II/silk fibroin/hyaluronic acid scaffold

Damage to articular cartilage is irreversible and its ability to heal is minimal. The development of articular cartilage in tissue engineering requires suitable biomaterials as scaffolds that provide a 3D natural microenvironment for the development and growth of articular cartilage. This study aims to investigate the applicability of a 3D printed CSH (collagen type II/silk fibroin/hyaluronic acid) scaffold for constructing cartilage tissue engineering. The results showed that the composite scaffold had a three-dimensional porous network structure with uniform pore sizes and good connectivity. The hydrophilicity of the composite scaffold was 1071.7 ± 131.6%, the porosity was 85.12 ± 1.6%, and the compressive elastic modulus was 36.54 ± 2.28 kPa. The creep and stress relaxation constitutive models were also established, which could well describe the visco-elastic mechanical behavior of the scaffold. The biocompatibility experiments showed that the CSH scaffold was very suitable for the adhesion and proliferation of chondrocytes. Under dynamic compressive loading conditions, it was able to promote cell adhesion and proliferation on the scaffold surface. The 3D printed CSH scaffold is expected to be ideal for promoting articular cartilage regeneration.

Engineered autologous nasal cartilage for repair of nasal septal perforations - a case series.

This phase I clinical trial assessed the use of autologous nasal chondrocyte tissue-engineered cartilage (N-TEC) for functional repair of nasal septal perforations (NSP). The most widely used technique to treat NSP, namely interposition grafting with a polydioxanone (PDS) plate combined with a deep temporal fascia (DTF) graft, is still suboptimal towards patient satisfaction and revision rates. Patients (n=5, all female, age range: 23-54 years) had a 0.5-2.0cm diameter NSP. N-TEC was manufactured by expansion and 3D culture of autologous nasal septum chondrocytes into Chondro-Gide® collagen membranes. N-TEC was then shaped intraoperatively and enveloped in the harvested DTF before suturing it into the NSP. Safety (primary outcome) was assessed by the number of serious adverse reactions (SAR) until 12 months. Secondary outcomes included feasibility, assessed by surgical graft manipulation, and efficacy, assessed using subjective scoring (Nasal Obstruction Symptom Evaluation, NOSE, and Visual Analogue Scale, VAS, scores) and objective breathing function tests. Structural closure of NSP after 12 months was defined using endoscopy and computed tomography (CT) scans. NSP treatment by N-TEC implantation was safe and feasible, as no SAR and no challenge in graft manipulation was recorded for any of the patients. One year postoperative, subjective scoring improved in all patients, unless already optimal (average improvement of 23 and 28.6 points out of 100 respectively for NOSE and VAS scores). Objective respiratory function overall confirmed - with the exception of one case - the observations above (average improvement of 172 ml/s). NSP were closed and the mucosae completely healed in three patients. Autologous N-TEC is a valid treatment for NSP and warrants further clinical tests.

Delivery Strategies of Growth Factors in Cartilage Tissue Engineering.

Cartilage plays an important role in supporting soft tissues, reducing joint friction, and distributing pressure. However, its self-repair capacity is limited due to the lack of blood vessels, nerves, and lymphatic systems. Tissue engineering offers a potential solution to promote cartilage regeneration by combining scaffolds, seed cells, and growth factors. Among these, growth factors play a critical role in regulating cell proliferation, differentiation, and extracellular matrix remodeling. However, their instability, susceptibility to degradation and potential side effects limit their effectiveness. This article reviews the main growth factors used in cartilage tissue engineering and their delivery strategies, including affinity-based delivery, carrier-assisted delivery, stimuli-responsive delivery, spatial structure-based delivery, and cell system-based delivery. Each method shows unique advantages in enhancing the delivery efficiency and specificity of growth factors but also faces challenges such as cost, biocompatibility, and safety. Future research needs to further optimize these strategies to achieve more efficient, safe, and economical delivery of growth factors, thereby advancing the clinical application of cartilage tissue engineering.

Chemofunctionalization of knitted silk to improve interface connection in a nano/micro scaffold based on polycaprolactone-chitosan-multi-walled carbon nanotube/silk.

Nano/micro hybrid scaffolds in long-term healing tissue engineering can simultaneously offer both mechanical and biological properties. In this study, a hybrid scaffold was fabricated through electrospinning of polycaprolactone (PCL)-chitosan (Cs)/ multi-walled carbon nanotubes (MWCNTs) based nanofibers onto a chemically functionalized knitted silk substrate (F-Silk) and the scaffold were evaluated with regard to morphology, chemical and crystalline structure, hydrophilicity, mechanical properties, bioactivity, biodegradability, and cellular behavior. Chemical functionalization of silk using N-hydroxysuccinimide (NHS) and 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) resulted in greater integrity in the formation of nanofibers onto the microfibers. The presence of MWCNTs significantly reduced the contact angle of the scaffolds from 79.72°±2.72 to 68.92°±5.63. Chemical functionalization of silk, the presence of nanofiber coating, and the presence of MWCNTs increased the ultimate tensile strength of the hybrid scaffolds by 18%, 20%, and 30% compared to raw silk fabric, respectively. The presence of MWCNTs and chemical functionalization of knitted silk increased the bioactivity and reduced the degradation rate of hybrid scaffolds. The increase in the amount of carboxyl groups as a result of adding 0.5wt% of MWCNTs significantly improved the adhesion, growth and proliferation of chondrocyte cells on the hybrid scaffolds as observed through cell morphology. According to the obtained results, hybrid scaffold based on PCL-Cs-MWCNTs/F-silk can be a suitable option for further research in cartilage tissue engineering.