Tissue Engineering Approaches Research Articles

Driving Osteocytogenesis from Mesenchymal Stem Cells in Osteon-like Biomimetic Nanofibrous Scaffolds.

The treatment of critical-sized bone defects caused by tumor removal, skeletal injuries, or infections continues to pose a major clinical challenge. A popular potential alternative solution to autologous bone grafts is a tissue-engineered approach that utilizes the combination of mesenchymal stromal/stem cells (MSCs) with synthetic biomaterial scaffolds. This approach aims to support new bone formation by mimicking many of the biochemical and biophysical cues present within native bone. Regrettably, osteocyte cells, crucial for bone maturation and homeostasis, are rarely produced within MSC-seeded scaffolds, thereby restricting the development of fully mature cortical bone from these synthetic implants. In this work, we have constructed a multimodal scaffold by combining electrospun poly(lactic-co-glycolic acid) (PLGA) fibrous scaffolds with poly(ethylene glycol) (PEG)-based hydrogels that mimic the functional unit of cortical bone, osteon (osteon-mimetic) scaffolds. These scaffolds were decorated with a novel bone morphogenic protein-6 (BMP6) peptide (BMP6p) after our findings revealed that the BMP6p drives higher levels of Smad signaling than the full-length protein counterpart, soluble or when bound to the PEG hydrogel backbone. We show that our osteon-mimetic scaffolds, in presenting concentric layers of BMP6p-PEG hydrogel overlaid on MSC-seeded PLGA nanofibers, promoted the rapid formation of osteocyte-like cells with a phenotypic dendritic morphology, producing early osteocyte markers, including E11/gp38 (E11). Maturation of these osteocyte-like cells was further confirmed by the observation of significant dentin matrix protein 1 (DMP1) throughout our bilayered scaffolds after 3 weeks, even when cultured in a medium without dexamethasone (DEX) or any other osteogenic supplements. These results demonstrate that these osteon-mimetic scaffolds, in presenting biochemical and topographical cues reminiscent of the forming osteon, can drive the formation of osteocyte-like cells in vitro from hBMSCs without the need for any osteogenic factor media supplementation.

Rapid and Controllable Multilayer Cell Sheet Assembly via Biodegradable Nanochannel Membranes

AbstractThe ability to precisely arrange and control the assembly of diverse cell types into intricate 3D structures remains a critical challenge in tissue engineering. Herein, a versatile and programmable 3D cell sheet assembly is described technology by developing a biodegradable nanochannel (BNC) membrane to fulfill this unmet need. This membrane, hierarchically assembled from 2D nanomaterial aggregates, exhibits both exceptional fluid permeability and rapid biodegradation under physiological conditions. The unique properties of the BNC membrane enable precise spatial and temporal control over cell assembly, facilitating the creation of complex 3D cellular architectures. The BNC membrane is integrated with a programmable negative‐pressure‐based cell assembly strategy to form single and multicellular 3D sheets in a highly controllable manner. To demonstrate the feasibility and translatability of this technology in the field of tissue engineering approaches to screen stem cell‐derived therapeutics with “core–shell” macrophage‐fibroblast multicellular patterns and treat murine diabetic skin wounds via scaffold‐free 3D adipose‐derived mesenchymal stem cell (ADMSC) sheets are devised. In summary, the results demonstrate that the BNC membrane‐based 3D cell sheet assembly approach significantly advances current tissue engineering capabilities, offering substantial potential for both regenerative medicine applications and the development of physiologically relevant disease models.

The landscape of clinical trials in corneal regeneration: A systematic review of tissue engineering approaches in corneal disease.

The limited availability of a healthy donor cornea and the incidence of allograft failure led researchers to seek other corneal substitutes via tissue engineering. Exploring the trend of clinical trials of the cornea with the vision of tissue engineering provides an opportunity to reveal future potential corneal substitutes. The results of this clinical trial are beneficial for future study designs to overcome the limitations of current therapeutic approaches. In this study, registered clinical trials of bio-based approaches were reviewed for corneal regeneration on March 22, 2024. Among the 3955 registered trials for the cornea, 392 trials were included in this study, which categorized in three main bio-based scaffolds, stem cells, and bioactive macromolecules. In addition to the acellular cornea and human amniotic membrane, several bio-based materials have been introduced as corneal substrates such as collagen, fibrin, and agarose. However, some synthetic materials have been introduced in recent studies to improve the desired properties of bio-based scaffolds for corneal substitutes. Nevertheless, new insights into corneal regenerative medicine have recently emerged from cell sheets with autologous and allogeneic cell sources. In addition, the future perspective of corneal regeneration is described through a literature review of recent experimental models.

Biodegradable conductive IPN in situ cryogels with anisotropic microchannels and sequential delivery of dual-growth factors for skeletal muscle regeneration

Biodegradable and anisotropic cryogels that simulate conductivity and ECM orientation structure of skeletal muscle, and release multiple growth factors, are expected for in situ skeletal muscle tissue engineering. Herein, biodegradable, conductive and anisotropic interpenetrating network (IPN) in situ cryogels are fabricated through Schiff base/acylhydrazone crosslinking via combining unidirectional freezing and cyclic freeze-thaw processes. The cryogels have good anisotropic mechanical properties and oriented microchannel structure, and induce the oriented alignment of myoblasts. The introduction of aniline tetramer enhances the mechanical properties and conductivity of the cryogels. The conductive cryogels significantly improve the proliferation and myogenic differentiation of C2C12 cells during 3D culture. The sequential delivery of insulin-like growth factor 1 (IGF-1) and vascular endothelial growth factor (VEGF) can induce migration of human umbilical vein endothelial cells (HUVECs), proliferation of human skin myofibroblasts (HMFB), and myogenic differentiation of C2C12 cells in vitro. In particular, conductive and anisotropic cryogels with dual-growth factors can significantly improve the repair efficiency of volumetric muscle loss (VML) in vivo. This study provides a new strategy to fabricate anisotropic and conductive IPN in situ cryogel biomimetic scaffolds that can encapsulate dual-growth factors and deliver them in time sequence, which significantly promote the efficient repair of VML via an in situ tissue engineering approach.

Cartilage-derived cells display heterogeneous pericellular matrix synthesis in agarose microgels

The pericellular matrix (PCM) surrounding chondrocytes is essential for articular cartilage tissue engineering. As the current isolation methods to obtain chondrocytes with their PCM (chondrons) result in a heterogeneous mixture of chondrocytes and chondrons, regenerating the PCM using a tissue engineering approach could prove beneficial. In this study, we aimed to discern the behavior of articular chondrocytes (ACs) in regenerating the PCM in such an approach and whether this would also be true for articular cartilage-derived progenitor cells (ACPCs), as an alternative cell source. Bovine ACs and ACPCs were encapsulated in agarose microgels using droplet-based microfluidics. ACs were stimulated with TGF-β1 and dexamethasone and ACPCs were sequentially stimulated with BMP-9 followed by TGF-β1 and dexamethasone. After 0, 3, 5, and 10 days of culture, PCM components, type-VI collagen and perlecan, and ECM component, type-II collagen, were assessed using flow cytometry and fluorescence microscopy. Both ACs and ACPCs synthesized the PCM before the ECM. It was seen for the first time that synthesis of type-VI collagen always preceded perlecan. While the PCM synthesized by ACs resembled native chondrons after only 5 days of culture, ACPCs often made less well-structured PCMs. Both cell types showed variations between individual cells and donors. On one hand, this was more prominent in ACPCs, but also a subset of ACPCs showed superior PCM and ECM regeneration, suggesting that isolating these cells may potentially improve cartilage repair strategies.

Endothelial cells-derived exosomes-based hydrogel improved tendinous repair via anti-inflammatory and tissue regeneration-promoting properties

Tendon injuries are common orthopedic ailments with a challenging healing trajectory, especially in cases like the Achilles tendon afflictions. The healing trajectory of tendon injuries is often suboptimal, leading to scar formation and functional impairment due to the inherent low metabolic activity and vascularization of tendon tissue. As pressing is needed for effective interventions, efforts are made to explore biomaterials to augment tendon healing. However, tissue engineering approaches face hurdles in optimizing tissue scaffolds and nanomedical strategies. To navigate these challenges, an injectable hydrogel amalgamated with human umbilical vein endothelial cells-derived exosomes (HUVECs-Exos) was prepared and named H-Exos-gel in this study, aiming to enhance tendon repair. In our research involving a model of Achilles tendon injuries in 60 rats, we investigated the efficacy of H-Exos-gel through histological assessments performed at 2 and 4 weeks and behavioral assessments conducted at the 4-week mark revealed its ability to enhance the Achilles tendon’s mechanical strength, regulate inflammation and facilitate tendon regeneration and functional recovery. Mechanically, the H-Exos-gel modulated the cellular behaviors of macrophages and tendon-derived stem cells (TDSCs) by inhibiting inflammation-related pathways and promoting proliferation-related pathways. Our findings delineate that the H-Exos-gel epitomizes a viable bioactive medium for tendon healing, heralding a promising avenue for the clinical amelioration of tendon injuries.

Raman spectroscopic investigation of polymer based magnetic multicomponent scaffolds

Scaffolds acting as an artificial matrix for cell proliferation are one of the bone tissue engineering approaches to the treatment of bone tissue defects. In the presented study, novel multicomponent scaffolds composed of a poly(ε-caprolactone) (PCL), phenolic compounds such as tannic (TA) and gallic acids (GA), and nanocomponents such as silica-coated magnetic iron oxide nanoparticles (MNPs-c) and functionalized multi-walled carbon nanotubes (CNTs) have been produced as candidates for such artificial substitutes. Well-developed interconnected porous structures were observed using scanning electron microscopy (SEM). Raman spectra showed that the highly crystalline nature of PCL was reduced by the addition of nanoadditives. In the case of scaffolds containing MNPs-c and TA, the formation of a Fe-TA complex was concluded because characteristic bands of chelation of the Fe3+ ion by phenolic catechol oxygen appeared. It was found that the necessary conditions for the crystallization of the PCL/MNPs-c/TA are for the catechol groups to be able to penetrate the porous silica shell of MNPs-c, as during experiment with MNPs-c and TA without polymer, no such complexation was observed. Moreover, the number of catechol groups, the spatial structure and molecular size of this phenolic compound are also crucial for complexation process because GA does not form complexes. Therefore, the PCL/CNTs/MNPs-c/TA scaffolds are interesting candidates to consider for their possible medical applications.

Biomimetic and non-biomimetic approaches in dura substitutes: the influence of mechanical properties.

The dura mater, the furthest and strongest layer of the meninges, is crucial for protecting the brain and spinal cord. Its biomechanical behavior is vital, as any alterations can compromise biological functions. In recent decades, interest in the dura mater has increased due to the need for hermetic closure of dural defects prompting the development of several substitutes. Collagen-based dural substitutes are common commercial options, but they lack the complex biological and structural elements of the native dura mater, impacting regeneration and potentially causing complications like wound/postoperative infection and cerebrospinal fluid leakage. To face this issue, recent tissue engineering approaches focus on creating biomimetic dura mater substitutes. The objective of this review is to discuss whether mimicking the mechanical properties of native tissue or ensuring high biocompatibility and bioactivity is more critical in developing effective dural substitutes, or if both aspects should be systematically linked. After a brief description of the properties and architecture of the native cranial dura, we describe the advantages and limitations of biomimetic dura mater substitutes to better understand their relevance. In particular, we consider biomechanical properties' impact on dura repair's effectiveness. Finally, the obstacles and perspectives for developing the ideal dural substitute are explored.

3D-printed Mg-incorporated PCL-based scaffolds improves rotator cuff tendon-bone healing through regulating macrophage polarization.

Introduction: Rotator cuff tear (RCT) is a common shoulder injury impacting mobility and quality of life, while traditional surgeries often result in poor healing. Tissue engineering offers a promising solution, with poly (ε-caprolactone) (PCL) being favored due to its slow degradation, biocompatibility, and non-toxicity. However, PCL lacks sufficient compression resistance. Incorporating Mg, which promotes bone growth and has antibacterial effects, could enhance RCT repair. Methods: The Mg-incorporated PCL-based scaffolds were fabricated using a 3D printing technique. The scaffolds were incorporated with different percentages of Mg (0%, 5%, 10%, 15%, and 20%). The osteogenic activities and anti-inflammatory properties of the scaffolds were evaluated in vitro using human osteoblasts and macrophages. The tissue ingrowth and biocompatibility of the scaffolds were assessed in vivo using a rat model of RCT repair. The ability of the scaffolds to enhance macrophage polarization towards the M2 subtype and inhibit inflammation signaling activation was also investigated. Results: It was found that when incorporated with 10% Mg, PCL-based scaffolds exhibited the optimal bone repairing ability in vitro and in vivo. The in vitro experiments indicated that the successfully constructed 10Mg/PCL scaffolds enhance osteogenic activities and anti-inflammatory properties. Besides, the in vivo studies demonstrated that 10Mg/PCL scaffolds promoted tissue ingrowth and enhanced biocompatibility compared to the control PCL scaffolds. Furthermore, the 10Mg/PCL scaffolds enhanced the macrophages' ability to polarize towards the M2 subtype and inhibited inflammation signaling activation. Discussion: These findings suggest that 3D-printed Mg-incorporated PCL scaffolds have the potential to improve RCT by enhancing osteogenesis, reducing inflammation, and promoting macrophage polarization. The incorporation of 10% Mg into PCL-based scaffolds provided the optimal combination of properties for RCT repair augmentation. This study highlights the potential of tissue engineering approaches in improving the outcomes of RCT repair and provides a foundation for future clinical applications.

Fabrication and Characterization of Collagen–Magnetic Particle Composite Microbeads for Targeted Cell Adhesion and Proliferation

The integration of the biocompatibility of collagen and the remote-control ability of magnetic elements serves as both a cell scaffold and an actuator. We studied the preparation, characterization, and potential applications of collagen–magnetic particle composite microbeads (CMPMBs). The interplay among collagen concentration, particle size, and surface roughness was found to influence cell adhesion and proliferation. Adsorption and desorption tests showed the reversible attachment of the particles to magnetic sheets, enabling precise spatial control and targeted cell delivery. The particles demonstrated their utility as cell carriers, supporting cell migration and proliferation. These findings showcase the potential of CMPMBs as a promising platform for advanced cell delivery and tissue regeneration applications. The ability to fine-tune particle properties and manipulate them using magnetic fields offers new possibilities for creating complex tissue constructs and controlling cellular behavior, which could contribute to the development of more effective regenerative therapies and tissue engineering approaches.

T. gondii excretory proteins promote the osteogenic differentiation of human bone mesenchymal stem cells via the BMP/Smad signaling pathway

BackgroundBone defects, resulting from substantial bone loss that exceeds the natural self-healing capacity, pose significant challenges to current therapeutic approaches due to various limitations. In the quest for alternative therapeutic strategies, bone tissue engineering has emerged as a promising avenue. Notably, excretory proteins from Toxoplasma gondii (TgEP), recognized for their immunogenicity and broad spectrum of biological activities secreted or excreted during the parasite’s lifecycle, have been identified as potential facilitators of osteogenic differentiation in human bone marrow mesenchymal stem cells (hBMSCs). Building on our previous findings that TgEP can enhance osteogenic differentiation, this study investigated the molecular mechanisms underlying this effect and assessed its therapeutic potential in vivo.MethodsWe determined the optimum concentration of TgEP through cell cytotoxicity and cell proliferation assays. Subsequently, hBMSCs were treated with the appropriate concentration of TgEP. We assessed osteogenic protein markers, including alkaline phosphatase (ALP), Runx2, and Osx, as well as components of the BMP/Smad signaling pathway using quantitative real-time PCR (qRT-PCR), siRNA interference of hBMSCs, Western blot analysis, and other methods. Furthermore, we created a bone defect model in Sprague-Dawley (SD) male rats and filled the defect areas with the GelMa hydrogel, with or without TgEP. Microcomputed tomography (micro-CT) was employed to analyze the bone parameters of defect sites. H&E, Masson and immunohistochemical staining were used to assess the repair conditions of the defect area.ResultsOur results indicate that TgEP promotes the expression of key osteogenic markers, including ALP, Runx2, and Osx, as well as the activation of Smad1, BMP2, and phosphorylated Smad1/5—crucial elements of the BMP/Smad signaling pathway. Furthermore, in vivo experiments using a bone defect model in rats demonstrated that TgEP markedly promoted bone defect repair.ConclusionOur results provide compelling evidence that TgEP facilitates hBMSC osteogenic differentiation through the BMP/Smad signaling pathway, highlighting its potential as a therapeutic approach for bone tissue engineering for bone defect healing.

Exploring the Potential of Skin Cell Culture and the Vital Role of Skin Grafts in Regenerative Medicine and Biology

The skin is acknowledged as the biggest organ, covering the exterior of the body and serving as a physical barrier. The integumentary system is made up of three layers of tissue: the epidermis, dermis, and hypodermis. For transplantation, epidermal cell cultures have been around for a while. The epidermal stem cells can proliferate and self-renew in a manner that allows for rapid healing since they are unipotent, meaning they can only produce one type of cell. In therapeutic terms, cultured keratinocytes have been described as an autologous cell-based therapy that provides a source of autologous tissue, reducing the need for large donor sites and minimizing the risk of immune rejection. This review explores the composition and functioning of the skin’s extracellular matrix, along with strategies to incorporate ECM components into the cell culture techniques. Rebuilding skin flaws without consideration for side effects is skin grafting. The tissue lacks its circulatory supply and must receive it from the bed in which it is inserted. The skin cells have contributed to developing skin graft and tissue engineering approaches for repairing damaged skin. Similar to grafting, the skin graft is divided into sections based on the quantity of dermis involved: split-thickness skin and full-thickness skin. Transplanting autologous keratinocytes is an alternative to autologous skin grafting. In the wound bed, epidermal stem cells encourage angiogenesis. After invading the fibrin wound clot, angiogenic capillary sprouts form a microvascular network throughout the granulation tissue in a few days. In this article, authors will review the current methods and application of skin cell culture for transplantation including different cell sources, culture conditions, and transplantation techniques. The future direction of this approach is in the context of regenerative medicine and tissue engineering.

Region-Specific Decellularization of Porcine Uterine Tube Extracellular Matrix: A New Approach for Reproductive Tissue-Engineering Applications.

The uterine tube extracellular matrix is a key component that regulates tubal tissue physiology, and it has a region-specific structural distribution, which is directly associated to its functions. Considering this, the application of biological matrices in culture systems is an interesting strategy to develop biomimetic tubal microenvironments and enhance their complexity. However, there are no established protocols to produce tubal biological matrices that consider the organ morphophysiology for such applications. Therefore, this study aimed to establish region-specific protocols to obtain decellularized scaffolds derived from porcine infundibulum, ampulla, and isthmus to provide suitable sources of biomaterials for tissue-engineering approaches. Porcine uterine tubes were decellularized in solutions of 0.1% SDS and 0.5% Triton X-100. The decellularization efficiency was evaluated by DAPI staining and DNA quantification. We analyzed the ECM composition and structure by optical and scanning electronic microscopy, FTIR, and Raman spectroscopy. DNA and DAPI assays validated the decellularization, presenting a significative reduction in cellular content. Structural and spectroscopy analyses revealed that the produced scaffolds remained well structured and with the ECM composition preserved. YS and HEK293 cells were used to attest cytocompatibility, allowing high cell viability rates and successful interaction with the scaffolds. These results suggest that such matrices are applicable for future biotechnological approaches in the reproductive field.

Biomimetic Approaches in Scaffold-Based Blood Vessel Tissue Engineering.

Cardiovascular diseases remain a leading cause of mortality globally, with atherosclerosis representing a significant pathological means, often leading to myocardial infarction. Coronary artery bypass surgery, a common procedure used to treat coronary artery disease, presents challenges due to the limited autologous tissue availability or the shortcomings of synthetic grafts. Consequently, there is a growing interest in tissue engineering approaches to develop vascular substitutes. This review offers an updated picture of the state of the art in vascular tissue engineering, emphasising the design of scaffolds and dynamic culture conditions following a biomimetic approach. By emulating native vessel properties and, in particular, by mimicking the three-layer structure of the vascular wall, tissue-engineered grafts can improve long-term patency and clinical outcomes. Furthermore, ongoing research focuses on enhancing biomimicry through innovative scaffold materials, surface functionalisation strategies, and the use of bioreactors mimicking the physiological microenvironment. Through a multidisciplinary lens, this review provides insight into the latest advancements and future directions of vascular tissue engineering, with particular reference to employing biomimicry to create systems capable of reproducing the structure-function relationships present in the arterial wall. Despite the existence of a gap between benchtop innovation and clinical translation, it appears that the biomimetic technologies developed to date demonstrate promising results in preventing vascular occlusion due to blood clotting under laboratory conditions and in preclinical studies. Therefore, a multifaceted biomimetic approach could represent a winning strategy to ensure the translation of vascular tissue engineering into clinical practice.

Impact of Hydroxyapatite on Gelatin/Oxidized Alginate 3D-Printed Cryogel Scaffolds.

Fabrication of scaffolds via 3D printing is a promising approach for tissue engineering. In this study, we combined 3D printing with cryogenic crosslinking to create biocompatible gelatin/oxidized alginate (Gel/OxAlg) scaffolds with large pore sizes, beneficial for bone tissue regeneration. To enhance the osteogenic effects and mechanical properties of these scaffolds, we evaluated the impact of hydroxyapatite (HAp) on the rheological characteristics of the 2.86% (1:1) Gel/OxAlg ink. We investigated the morphological and mechanical properties of scaffolds with low, 5%, and high 10% HAp content, as well as the resulting bio- and osteogenic effects. Scanning electron microscopy revealed a reduction in pore sizes from 160 to 180 µm (HAp-free) and from 120 to 140 µm for both HAp-containing scaffolds. Increased stability and higher Young's moduli were measured for 5% and 10% HAp (18 and 21 kPa, respectively) compared to 11 kPa for HAp-free constructs. Biological assessments with mesenchymal stem cells indicated excellent cytocompatibility and osteogenic differentiation in all scaffolds, with high degree of mineralization in HAp-containing constructs. Scaffolds with 5% HAp exhibited improved mechanical characteristics and shape fidelity, demonstrated positive osteogenic impact, and enhanced bone tissue formation. Increasing the HAp content to 10% did not show any advantages in osteogenesis, offering a minor increase in mechanical strength at the cost of significantly compromised shape fidelity.

Tissue engineering approach to the creation of grafting material for rhinoplasty: clinical сase reports

The use of autologous cartilage and bone grafts remains the gold standard in augmentation rhinoplasty performed to reconstruct of the nasal dorsum. Meanwhile, limited number of available sources, donor site morbidity, and unpredictable graft resorption represent significant disadvantages of autografting. The aim of this study is to test combination of autologous stromal vascular fraction (SVF) and commercially available bone substitutes (BSs) as new tissue-engineered grafting material (GM) for rhinoplasty. A series of consecutive cases includes four adult patients who underwent rhinoplasty to correct saddle nose deformity (SND) using the new graft technique. SVF was isolated from liposuction aspirate using standard methodology of enzymatic digestion. Two types of BSs were combined with SVF: Bio-Oss granules to create a moldable graft (M-graft), and block-shaped BoneMedik-S to create rigid grafts (R-grafts). The moderate SND was treated using an M-graft. In case of major or complex SND, the nasal dorsum was reconstructed with dorso-columellar L-shaped framework made of R-grafts. The results were evaluated over a period of 6 months to 3 years postoperatively using photogrammetry and FACE-Q appearance appraisal scales. Computerised tomography (CT) scanning of the reconstructed nose and histological analysis of grafted material were also carried out. No complications were observed. The photograms show the restoration of the correct contour of the nose. FACE-Q appraisal scale scores increased significantly, including satisfaction with nose appearance, psychological well-being, and social function. In CT evaluation, there was no substantial resorption or warping of the grafts. Histological findings show osteogenic remodeling of the grafted material. Thus, combining autologous SVF with BSs is a promising strategy for developing rhinoplasty GM.

Comparative analysis of scaffold fibre diameter-modulated responses on immortalized and primary thyroid cells: Implications for thyroid regeneration

Primary hypothyroidism results from thyroid gland damage, commonly due to radiotherapy for head and neck cancer. Primary hypothyroidism severely impacts patient quality of life and is expected to increase in incidence due to the aging population and rising cancer survivor rates. Tissue engineering approaches are starting to emerge as a potential treatment.Electrospinning techniques have yet to be investigated in conjunction with thyroid tissue. Here, electrospun polycaprolactone scaffolds with varying fibre diameters were fabricated and their effects on immortalized human thyrocytes (Nthy-ori 3–1) and primary murine thyroid cells were investigated. Four groups of scaffolds were produced with fibre diameters ranging from approximately 0.5 µm to 4 µm, to understand the impact of these microenvironments on their potential for thyroid regeneration.Results showed that fibre size influenced mechanical properties, porosity and cell response. Nthy-ori 3–1 cells performed best on the scaffold with medium-sized fibres while primary cells preferred the scaffold with larger fibres. Nonetheless, the scaffold with the smallest fibre diameter encouraged the secretion of collage-like fibrils, potentially indicating favourable conditions for regeneration.This study highlights the potential of electrospun PCL scaffolds as promising candidates for tissue engineering applications in the treatment of primary hypothyroidism. The findings demonstrate the importance of tailoring scaffold properties and considering cell-type specific responses when designing biomaterials for tissue-engineered solutions for thyroid regeneration. Further research is necessary to elucidate the underlying mechanisms and optimize scaffold properties for successful thyroid tissue regeneration.

Vascularization of kidney organoids: different strategies and perspectives

Kidney diseases such as glomerulopathy and nephron dysfunction are estimated to grow to more than 900 million cases by 2030, in 45% of which kidney transplantation will be required, representing a major challenge for biomedicine. A wealth of progress has been made to model human diseases using induced pluripotent stem cells (iPSCs) in vitro differentiated to a variety of organoids, including kidney organoids, and in developing various microfluidics-based organ-on-a-chip (OoC) systems based on them. With the combination of targeted gene editing capacities, relevant polymorphic genetic variants can be established in such organoid models to advance evidence-based medicine. However, the major drawback of the current organoid disease models is the lack of functional endothelial vasculature, which especially concerns the kidney, the function of which is strongly associated with blood flow. The design of novel medical devices using tissue engineering approaches such as kidney organoids is also strongly dependent on the understanding of the fundamental principles of nephrogenesis and the vascularization of organs and tissues. Developmental vascularization of the kidney has been an area of intense research for decades. However, there is still no consensus among researchers on how exactly the vascularization of the kidney occurs in normal and pathological conditions. This lack of consensus is partly due to the lack of an appropriate model system to study renal vascularization during nephrogenesis. In this review, we will describe recent progress in the areas of kidney vasculature development, kidney organoids in general and assembled on microfluidic devices in particular. We will focus on the in vitro vasculature of kidney organoids in microfluidic OoC model systems to study kidney diseases and on the perspectives of tissue engineering for the modeling of kidney diseases and the design of bioartificial medical devices. We also aim to summarize the information related to the key mechanisms of intercellular communication during nephrogenesis and the formation of the renal vasculature in an OoC setup.

Polydopamine-mediated immobilization of BMP-2 onto electrospun nanofibers enhances bone regeneration

Dealing with bone defects is a significant challenge to global health. Electrospinning in bone tissue engineering has emerged as a solution to this problem. In this study, we designed a PVDF-b-PTFE block copolymer by incorporating TFE, which induced a phase shift in PVDF from α to β, thereby enhancing the piezoelectric effect. Utilizing the electrospinning process, we not only converted the material into a film with a significant surface area and high porosity but also intensified the piezoelectric effect. Then we used polydopamine to immobilize BMP-2 onto PVDF-b-PTFE electrospun nanofibrous membranes, achieving a controlled release of BMP-2. The scaffold’s characters were examined using SEM and XRD. To assess its osteogenic effects in vitro, we monitored the proliferation of MC3T3-E1 cells on the fibers, conducted ARS staining, and measured the expression of osteogenic genes. In vivo, bone regeneration effects were analyzed through micro-CT scanning and HE staining. ELISA assays confirmed that the sustained release of BMP-2 can be maintained for at least 28 d. SEM images and CCK-8 results demonstrated enhanced cell viability and improved adhesion in the experimental group. Furthermore, the experimental group exhibited more calcium nodules and higher expression levels of osteogenic genes, including COL-I, OCN, and RUNX2. HE staining and micro-CT scans revealed enhanced bone tissue regeneration in the defective area of the PDB group. Through extensive experimentation, we evaluated the scaffold’s effectiveness in augmenting osteoblast proliferation and differentiation. This study emphasized the potential of piezoelectric PVDF-b-PTFE nanofibrous membranes with controlled BMP-2 release as a promising approach for bone tissue engineering, providing a viable solution for addressing bone defects.

Platelet Power: Revitalizing Endodontics With Scaffolds.

This article provides an overview of a biologically based method for restoring damaged tooth structures and pulp tissues known as regenerative endodontics. It explores the concept of regenerative endodontics, its tissue engineering approach, and its application inmaintaining vitality. The article discusses the significance of the factors affecting growth, scaffolds, and stem cells being the three tissue engineering components involved in the regeneration of pulp tissues. It also delves into the classification of scaffolds and the role of platelet-rich fibrin (PRF) and platelet-rich plasma (PRP) as biological scaffolds. The methodology section details the search process for relevant studies, and the review section presents research findings associated with PRF and its application in regeneration and repair of tissue. The article concludes by highlighting the potential of advanced PRF and injectable PRF in regenerative endodontics, with a focus on their impact on tissue regeneration and healing.