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Albumin has attracted interest in the field of tissue engineering for fabricating three-dimensional scaffolds due to its stability, unique ligand-binding property, biocompatibility, high solubility and low cost. This study aimed to develop a versatile fluorescent scaffold using human serum albumin (HSA), HSA-capped gold nanoclusters (HSA@AuNCs) and oxidized dextran. The morphological, structural, mechanical and physical properties of the constructs were evaluated using FTIR, SEM, thermogravimetric analysis, swelling, compression, in vitro biocompatibility and degradation tests. Traceability was demonstrated by fluorescence imaging, while Au release from scaffolds was determined by inductively coupled plasma-optical emission spectroscopy. Cell adhesion and proliferation on scaffolds were evaluated using mesenchymal stem cells (MSCs), cellular metabolic activity was assessed by alamarBlue assay for 10 days. The alkaline phosphatase activity of MSCs was followed for up to 21 days. The findings revealed that the HSA/AuNC scaffolds are fluorescent, biodegradable and exhibit good in vitro biocompatibility. In addition, the nanocomposite scaffolds provide a suitable environment for MSCs to adhere, proliferate and maintain their metabolic activities. This work is expected to pave the way for the design of albumin-based scaffolds with different bioactive agents that can be conjugated to the albumin backbone. [Display omitted] • Green synthesis of gold nanoclusters (AuNCs) is performed. • AuNCs with high fluorescence emission are chemically incorporated into HSA scaffold. • HSA/AuNC can be an ideal tissue scaffold for in vivo imaging. • HSA/AuNC scaffold is traceable, xeno-free and customizable. [ABSTRACT FROM AUTHOR]

Electrospinning technology is widely used for preparing biological tissue engineering scaffolds because of its advantages of simple preparation, accurate process parameters, and easy control. Poly(L-lactide) (PLLA) is regarded as a promising biomass-based polymer for use in electrospinning. The incorporation of Fe3O4 nanoparticles (NPs) could improve the osteogenic differentiation and proliferation of cells in the presence or absence of a static magnetic field (SMF). In this work, these two materials were blended together to obtain electrospun samples with better dispersibility and improved magnetic properties. First, composite PLLA and Fe3O4 NP fibers were prepared by means of electrospinning. The influence of electrospinning conditions on the morphology of the composite fibers was then discussed. Changes in magnetic properties and thermal stability resulting from the use of different PLLA/Fe3O4 mass ratios were also considered. Next, the morphology, crystal state, thermodynamic properties, and magnetic properties of the electrospun samples were determined using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and vibration sample magnetization (VSM). The results showed that the fibers prepared using PLLA with Mn = 170,000 exhibited good morphology when electrospun at 12 KV. The magnetic properties of PLLA/Fe3O4 composite electrospun fibers increased with the NP content, with the exception of thermal stability. The results of the present study may help to promote the further development of PLLA/Fe3O4 composite materials in the biomedical field. [ABSTRACT FROM AUTHOR]

Enzyme activity is regulated by several mechanisms, including phosphorylation. Phosphorylation is a key signal transduction process in all eukaryotic cells and is thus crucial for virtually all cellular processes. In addition to its direct effect on protein structure, phosphorylation also affects protein-protein interactions, such as binding to scaffolding 14-3-3 proteins, which selectively recognize phosphorylated motifs. These interactions then modulate the catalytic activity, cellular localisation and interactions of phosphorylated enzymes through different mechanisms. The aim of this mini-review is to highlight several examples of 14-3-3 protein-dependent mechanisms of enzyme regulation previously studied in our laboratory over the past decade. More specifically, we address here the regulation of the human enzymes ubiquitin ligase Nedd4-2, procaspase-2, calciumcalmodulin dependent kinases CaMKK1/2, and death-associated protein kinase 2 (DAPK2) and yeast neutral trehalase Nth1. [ABSTRACT FROM AUTHOR]

Osteocytes perceive and process mechanical stimuli in the lacuno-canalicular network in bone. As a result, they secrete signaling molecules that mediate bone formation and resorption. To date, few three-dimensional (3D) models exist to study the response of mature osteocytes to biophysical stimuli that mimic fluid shear stress and substrate strain in a mineralized, biomimetic bone-like environment. Here we established a biomimetic 3D bone model by utilizing a state-of-art perfusion bioreactor platform where immortomouse/Dmp1-GFP-derived osteoblastic IDG-SW3 cells were differentiated into mature osteocytes. We evaluated proliferation and differentiation properties of the cells on 3D microporous scaffolds of decellularized bone (dBone), poly(L-lactide-co-trimethylene carbonate) lactide (LTMC), and beta-tricalcium phosphate (β-TCP) under physiological fluid flow conditions over 21 days. Osteocyte viability and proliferation were similar on the scaffolds with equal distribution of IDG-SW3 cells on dBone and LTMC scaffolds. After seven days, the differentiation marker alkaline phosphatase (Alpl), dentin matrix acidic phosphoprotein 1 (Dmp1), and sclerostin (Sost) were significantly upregulated in IDG-SW3 cells (p = 0.05) on LTMC scaffolds under fluid flow conditions at 1.7 ml/min, indicating rapid and efficient maturation into osteocytes. Osteocytes responded by inducing the mechanoresponsive genes FBJ osteosarcoma oncogene (Fos) and prostaglandin-endoperoxide synthase 2 (Ptgs2) under perfusion and dynamic compressive loading at 1 Hz with 5 % strain. Together, we successfully created a 3D biomimetic platform as a robust tool to evaluate osteocyte differentiation and mechanobiology in vitro while recapitulating in vivo mechanical cues such as fluid flow within the lacuno-canalicular network. This study highlights the importance of creating a three-dimensional (3D) in vitro model to study osteocyte differentiation and mechanobiology, as cellular functions are limited in two-dimensional (2D) models lacking in vivo tissue organization. By using a perfusion bioreactor platform, physiological conditions of fluid flow and compressive loading were mimicked to which osteocytes are exposed in vivo. Microporous poly(L-lactide-co-trimethylene carbonate) lactide (LTMC) scaffolds in 3D are identified as a valuable tool to create a favorable environment for osteocyte differentiation and to enable mechanical stimulation of osteocytes by perfusion and compressive loading. The LTMC platform imitates the mechanical bone environment of osteocytes, allowing the analysis of the interaction with other cell types in bone under in vivo biophysical stimuli. [Display omitted] [ABSTRACT FROM AUTHOR]

Applied to the epicardium in-vivo , regenerative cardiac patches support the ventricular wall, reduce wall stresses, encourage ventricular wall thickening, and improve ventricular function. Scaffold engraftment, however, remains a challenge. After implantation, scaffolds are subject to the complex, time-varying, biomechanical environment of the myocardium. The mechanical capacity of engineered tissue to biomimetically deform and simultaneously support the damaged native tissue is crucial for its efficacy. To date, however, the biomechanical response of engineered tissue applied directly to live myocardium has not been characterized. In this paper, we utilize optical imaging of a Langendorff ex-vivo cardiac model to characterize the native deformation of the epicardium as well as that of attached engineered scaffolds. We utilize digital image correlation, linear strain, and 2D principal strain analysis to assess the mechanical compliance of acellular ice templated collagen scaffolds. Scaffolds had either aligned or isotropic porous architecture and were adhered directly to the live epicardial surface with either sutures or cyanoacrylate glue. We demonstrate that the biomechanical characteristics of native myocardial deformation on the epicardial surface can be reproduced by an ex-vivo cardiac model. Furthermore, we identified that scaffolds with unidirectionally aligned pores adhered with suture fixation most accurately recapitulated the deformation of the native epicardium. Our study contributes a translational characterization methodology to assess the physio-mechanical performance of engineered cardiac tissue and adds to the growing body of evidence showing that anisotropic scaffold architecture improves the functional biomimetic capacity of engineered cardiac tissue. Engineered cardiac tissue offers potential for myocardial repair, but engraftment remains a challenge. In-vivo , engineered scaffolds are subject to complex biomechanical stresses and the mechanical capacity of scaffolds to biomimetically deform is critical. To date, the biomechanical response of engineered scaffolds applied to live myocardium has not been characterized. In this paper, we utilize optical imaging of an ex-vivo cardiac model to characterize the deformation of the native epicardium and scaffolds attached directly to the heart. Comparing scaffold architecture and fixation method, we demonstrate that sutured scaffolds with anisotropic pores aligned with the native alignment of the superficial myocardium best recapitulate native deformation. Our study contributes a physio-mechanical characterization methodology for cardiac tissue engineering scaffolds. [Display omitted] [ABSTRACT FROM AUTHOR]

The use of decellularized extracellular matrix products in tissue regeneration is quite alluring yet practically challenging due to the limitations of its availability, harsh processing techniques, and host rejection. Scaffolds obtained by either incorporating extracellular matrix (ECM) material or coating the surface can resolve these challenges to some extent. However, these scaffolds lack the complex 3D network formed by proteins and growth factors observed in natural ECM. This study introduces an approach utilizing 3D nanofiber scaffolds decorated with dECM to enhance cellular responses and promote tissue regeneration. Notably, the dECM can be customized according to specific cellular requirements, offering a tailored environment for enhanced therapeutic outcomes. Two types of 3D expanded scaffolds, namely radially aligned scaffolds (RAS) and laterally expanded scaffolds (LES) fabricated by the gas-foaming expansion were utilized. To demonstrate the proof-of-concept, human dermal fibroblasts (HDFs) seeded on these scaffolds for up to 8 weeks, resulted in uniform and highly aligned cells which deposited ECM on the scaffolds. These cellular components were then removed from the scaffolds through decellularization (e.g., SDS treatment and freeze-thaw cycles). The dECM-decorated 3D expanded nanofiber scaffolds can direct and support cell alignment and proliferation along the underlying fibers upon recellularization. An in vitro inflammation assay indicates that dECM-decorated LES induces a lower immune response than dECM-decorated RAS. Further, subcutaneous implantation of dECM-decorated RAS and LES shows higher cell infiltration and angiogenesis within 7 and 14 days than RAS and LES without dECM decoration. Taken together, dECM-decorated 3D expanded nanofiber scaffolds hold great potential in tissue regeneration and tissue modeling. Decellularized ECM scaffolds have attained widespread attention in biomedical applications due to their intricate 3D framework of proteins and growth factors. Mimicking such a complicated architecture is a clinical challenge. In this study, we developed natural ECM-decorated 3D electrospun nanofiber scaffolds with controlled alignments to mimic human tissue. Fibroblasts were cultured on these scaffolds for 8 weeks to deposit natural ECM and decellularized by either freeze-thawing or detergent to obtain decellularized ECM scaffolds. These scaffolds were tested in both in-vitro and in-vivo conditions. They displayed higher cellular attributes with lower immune response making them a good grafting tool in tissue regeneration. [Display omitted] [ABSTRACT FROM AUTHOR]

Polycaprolactone (PCL) is a pivotal biopolymer in biomedicine, especially in tissue engineering for scaffolds and biomaterials. Recognized for its effectiveness as a drug carrier with superior controlled release properties, PCL is commonly processed via electrospinning, typically employing chlorinated or fluorinated solvents known for cellular toxicity. As an environmentally conscious alternative, this study explores glacial acetic acid (AA) as a solvent for electrospinning solutions. Investigating PCL's molecular degradation through acid hydrolysis in acidic solvents (AA/formic acid) (FA), the study assesses the impact of storage time on resulting structures. Solutions containing 30% PCL in AA/FA (9:1) were stored at 35°C for up to 14 days, revealing a 50% molar mass reduction during solubilization through gel permeation chromatography, x‐ray diffraction, and Fourier‐transform infrared analyses. This reduction influenced chain packing, raising crystallinity indices from approximately 37% to 49% with prolonged storage. The reduced molar mass resulted in unstable Taylor cones, generating diverse mat morphologies. Intriguingly, this degradation enhanced water adsorption capacity, indicating exposed hydrogen bonds from acid hydrolysis as an advantageous trait for regenerative medicine. This underscores the hydrolyzed materials' potential for cell anchoring in tissue engineering. [ABSTRACT FROM AUTHOR]

Tissue engineering, a rapidly advancing field in medicine, has made significant strides with the development of artificial tissue substitutes to meet the growing need for organ transplants. Three-dimensional (3D) porous scaffolds are widely utilized in tissue engineering, especially in orthopedic surgery. This study investigated the fluidic properties of diamond and gyroid structures with varying porosity levels (50–80%) using Computational Fluid Dynamics (CFD) analysis. The pressure and velocity distributions were analyzed, and it was observed that the pressure decreased gradually, whereas the velocity increased in the central area of the surface structures. Specifically, the pressure drop ranged from 2.079 to 0.984 Pa for the diamond structure and from 1.669 to 0.943 Pa for the gyroid structure as the porosity increased from 50% to 80%. It was also found that the permeability increased as the porosity level increased, with values ranging from 2.424 × 10 − 9 to 5.122 × 10 − 9   m 2 for the diamond structure and from 2.966 × 10 − 9 to 5.344 × 10 − 9   m 2 for the gyroid structure. The wall shear stress (WSS) was also analyzed, showing a consistent decrease with increased porosity for both types of structures, with WSS values ranging from 9.903 × 10 − 2 to 9.840 × 10 − 1   P a for the diamond structure and from 1.150 × 10 − 1 to 7.717 × 10 − 2   P a for the gyroid structure. Overall, this study provides insights into the fluidic properties of diamond and gyroid structures, which can be useful in various applications such as tissue engineering. [ABSTRACT FROM AUTHOR]

Introduction: Physical factors like stiffness and surface features are among the characteristics that affect the performance of barrier membranes and determine the results of regenerative processes. A perfect equilibrium between the membrane's rigidity and mechanical stability guarantees effective periodontal regeneration. The study's novelty lies in comparing the physical characteristics, namely morphology, tensile strength, wettability, and biological characteristics, namely biocompatibility and enzyme resistance properties, of the Fix-GideTM membrane against the gold standard membrane, Bio-Gide®. Aim: To explore the physical and biological properties of two commercially available barrier membranes in oral tissue regeneration. Materials and Methods: The present in-vitro study compared two commercially available membranes, namely Bio-Gide® and Fix-GideTM. Both membranes are bilayered resorbable membranes, with Bio-Gide composed of porcine dermis Type-I and III collagen and Fix-GideTM of bovine origin. The study was conducted at the Central Leather Research Institute, and the membranes were procured from Sri Ramachandra Institute of Higher Education and Research. Morphological characterisation was done using Scanning Electron Microscopy (SEM). Physical properties were evaluated using a tensile strength test, enzyme resistance test, and wettability measurement. Biocompatibility assessment was also performed. The Statistical Package for Social Sciences (SPSS) software was used to run the Mann-Whitney U test to analyse the statistical data obtained in the enzyme resistance test. Results: Biocompatibility assessment showed no cytotoxic profile of both membranes, portraying their biocompatible nature. Morphological analysis using SEM showed the surface of the Bio-Gide® membrane to be considerably smoother than the Fix-GideTM membrane. Both membranes, however, have fibrous and porous features on their inner surfaces. Tensile strength assessment found that the percentage of elongation was better with Bio-Gide (1.7±0.4 and 4.8±0.4) when compared to Fix-Gide (15.8±0.2 and 2.2±0.2) in both wet and dry states, respectively. The enzyme resistance test evaluated in dry and wet settings showed that the membranes, namely, Bio-Gide® membrane exhibited around 29±2% of degradation, whereas the Fix-GideTM exhibited only 18±2%. These mechanical profiles exhibited that the membranes has appreciable differences, although there wasn't a statistically significant difference between them (p=0.68). According to wettability studies, Bio-Gide is hydrophilic, but Fix-GideTM is hydrophobic. Conclusion: The observations of the present study showed that Fix-Gide had comparable physio-biological properties to that of the Bio-Gide membrane. This supports the suitability of the use of both membranes for various oral tissue regeneration procedures. [ABSTRACT FROM AUTHOR]

By promoting tissue regeneration, porous nano‐scaffolds offer improved chances for the maintenance, repair, and enhancement of damaged tissues and organ functioning. In this study, the nanosilica extract obtained from the agricultural waste, that is, rice husk after surface modification shows higher hydrophobicity in the hexamethyldisilazane and methyltrimethoxysilane‐modified nanosilica and hydrophilic nature in 3‐aminopropyl triethoxysilane‐modified nanosilica. Fourier transform infrared spectroscopy results reveal the functional groups exist in the scaffold and its surface morphology was evaluated by Field emission scanning electron microscope/energy dispersive X‐ray analysis which shows a cross‐network structure that could impart the proper cell adhesion. The presence of amorphous nanosilica in ultrapure form was confirmed using X‐ray diffraction analysis where a broad peak was obtained in the range of 15°–40°. The crystallization phase of the hybrid scaffold shows 2θ values obtained at 22.6°, 28.7°, and 40.6°. The graph thus obtained confirms that the material used is 3‐aminopropyl‐triethoxysilane‐modified silk/silica nanocomposite. The decomposition rates and temperature of the composite were analyzed using the thermogravimetry/differential thermal technique. The antibacterial activity of the hybrid scaffolds and silk and silica shows the metabolic pathways were not disrupted for both Gram‐positive and ‐negative microbes. Cell cytotoxicity analysis proved that the electrospun hybrid scaffold was nontoxic to L929 cells and promoted cell adhesion and growth. The cells were highly proliferated onto the surface layers in a regular systematic pattern thus proving that these scaffolds were suitable for bone regeneration applications. Hence these economically viable scaffolds turn to be biocompatible and are promising as a novel product for cell culture regneration realted to therapy. [ABSTRACT FROM AUTHOR]

Cell spheroids are an important three-dimensional (3D) model for in vitro testing and are gaining interest for their use in clinical applications. More natural 3D cell culture environments that support cell–cell interactions have been created for cancer drug discovery and therapy applications, such as the scaffold-free 3D Petri Dish® technology. This technology uses reusable and autoclavable silicone micro-molds with different topographies, and it conventionally uses gelled agarose for hydrogel formation to preserve the topography of the selected micro-mold. The present study investigated the feasibility of using a patterned Poly(vinyl alcohol) hydrogel using the circular topography 12–81 (9 × 9 wells) micro-mold to form HeLa cancer cell spheroids and compare them with the formed spheroids using agarose hydrogels. PVA hydrogels showed a slightly softer, springier, and stickier texture than agarose hydrogels. After preparation, Fourier transform infrared (FTIR) spectra showed chemical interactions through hydrogen bonding in the PVA and agarose hydrogels. Both types of hydrogels favor the formation of large HeLa spheroids with an average diameter of around 700–800 µm after 72 h. However, the PVA spheroids are more compact than those from agarose, suggesting a potential influence of micro-mold surface chemistry on cell behavior and spheroid formation. This was additionally confirmed by evaluating the spheroid size, morphology, integrity, as well as E-cadherin and Ki67 expression. The results suggest that PVA promotes stronger cell-to-cell interactions in the spheroids. Even the integrity of PVA spheroids was maintained after exposure to the drug cisplatin. In conclusion, the patterned PVA hydrogels were successfully prepared using the 3D Petri Dish® micro-molds, and they could be used as suitable platforms for studying cell–cell interactions in cancer drug therapy. [ABSTRACT FROM AUTHOR]

Tissue engineering is based on combining cells with suitable scaffolds and growth factors. Recently, bone tissue engineering has been especially investigated deeply due to a large number of bone-related diseases. One approach to improve scaffolds is based on using piezoelectric materials as a way to influence the growing bone tissue by mechanical stress. Another method to stimulate tissue growth is by applying an external magnetic field to composites of magnetostrictive and piezoelectric materials, as well as the possibility to prepare oriented surfaces by orienting embedded magnetic fibers or nanoparticles. In addition, magnetic scaffolds without other special properties have also been reported to show improved properties for bone tissue and other tissue engineering. Here, we provide an overview of recent research on magnetic scaffolds for tissue engineering, differentiating between bone and other tissue engineering. We show the advantages of magnetic scaffolds, especially related to cell guidance and differentiation, and report recent progress in the production and application of such magnetic substrates for different areas of tissue engineering. [ABSTRACT FROM AUTHOR]

Advanced periodontitis poses a significant threat to oral health, causing extensive damage and loss of both hard and soft periodontal tissues. While traditional therapies such as scaling and root planing can effectively halt the disease's progression, they often fail to fully restore the original architecture and function of periodontal tissues due to the limited capacity for spontaneous regeneration. To address this challenge, periodontal tissue engineering has emerged as a promising approach. This technology centers on the utilization of biomaterial scaffolds, which function as three-dimensional (3D) templates or frameworks, supporting and guiding the regeneration of periodontal tissues, including the periodontal ligament, cementum, alveolar bone, and gingival tissue. These scaffolds mimic the extracellular matrix (ECM) of native periodontal tissues, aiming to foster cell attachment, proliferation, differentiation, and, ultimately, the formation of new, functional periodontal structures. Despite the inherent challenges associated with preclinical testing, the intensification of research on biomaterial scaffolds, coupled with the continuous advancement of fabrication technology, leads us to anticipate a significant expansion in their application for periodontal tissue regeneration. This review comprehensively covers the recent advancements in biomaterial scaffolds engineered specifically for periodontal tissue regeneration, aiming to provide insights into the current state of the field and potential directions for future research. [ABSTRACT FROM AUTHOR]

Bone defects are a global health concern; bone tissue engineering (BTE) is the most promising alternative to reduce patient morbidity and overcome the inherent drawbacks of autograft and allograft bone. Three-dimensional scaffolds are pivotal in this field due to their potential to provide structural support and mimic the natural bone microenvironment. Following an already published protocol, a 3D porous structure consisting of alginate and hydroxyapatite was prepared after a gelation step and a freezing-drying step. Despite the frequent use of alginate in tissue regeneration, the biological inertness of this polysaccharide hampers proper cell colonization and proliferation. Therefore, the purpose of this work was to enhance the biological properties by promoting the interaction and adhesion between cells and biomaterial with the use of Fibronectin. This extracellular matrix protein was physically adsorbed on the scaffold, and its presence was evaluated with environmental scanning electron microscopy (eSEM) and the Micro-Bicinchoninic Acid (μBCA) protein assay. The MG-63 cell line was used for both static and dynamic (i.e., in bioreactor) 3D cell culturing on the scaffolds. The use of the bioreactor allowed for a better exchange of nutrients and oxygen and a better removal of cell catabolites from the inner portion of the construct, mimicking the physiological environment. The functionalized scaffolds showed an improvement in cell proliferation and colonization compared to non-functionalized ones; the effect of the addition of Fibronectin was more evident in the dynamic culturing conditions, where the cells clearly adhered on the surface of functionalized scaffolds. [ABSTRACT FROM AUTHOR]

Human mesenchymal stromal cells (hMSCs), whether used alone or together with three-dimensional scaffolds, are the best-studied postnatal stem cells in regenerative medicine. In this study, innovative composite scaffolds consisting of a core–shell architecture were seeded with bone-marrow-derived hMSCs (BM-hMSCs) and tested for their biocompatibility and remarkable capacity to promote and support bone regeneration and mineralization. The scaffolds were prepared by grafting three different amounts of gelatin–chitosan (CH) hydrogel into a 3D-printed polylactic acid (PLA) core (PLA-CH), and the mechanical and degradation properties were analyzed. The BM-hMSCs were cultured in the scaffolds with the presence of growth medium (GM) or osteogenic medium (OM) with differentiation stimuli in combination with fetal bovine serum (FBS) or human platelet lysate (hPL). The primary objective was to determine the viability, proliferation, morphology, and spreading capacity of BM-hMSCs within the scaffolds, thereby confirming their biocompatibility. Secondly, the BM-hMSCs were shown to differentiate into osteoblasts and to facilitate scaffold mineralization. This was evinced by a positive Von Kossa result, the modulation of differentiation markers (osteocalcin and osteopontin), an expression of a marker of extracellular matrix remodeling (bone morphogenetic protein-2), and collagen I. The results of the energy-dispersive X-ray analysis (EDS) clearly demonstrate the presence of calcium and phosphorus in the samples that were incubated in OM, in the presence of FBS and hPL, but not in GM. The chemical distribution maps of calcium and phosphorus indicate that these elements are co-localized in the same areas of the sections, demonstrating the formation of hydroxyapatite. In conclusion, our findings show that the combination of BM-hMSCs and PLA-CH, regardless of the amount of hydrogel content, in the presence of differentiation stimuli, can provide a construct with enhanced osteogenicity for clinically relevant bone regeneration. [ABSTRACT FROM AUTHOR]

Polydopamine, a mussel-inspired self-adherent polymer of dopamine, has impressive adhesive properties and thus is one of the most versatile approaches to functionalize tissue engineering scaffolds. To date, many types of polydopamine-functionalized scaffolds have been manufactured and extensively applied in bone tissue engineering at the preclinical stage. However, how polydopamine is biodegraded and metabolized during the bone healing process and the side effects of its metabolite remain largely unknown. These issues are often neglected in the modern manufacture of polydopamine-functionalized materials and restrict them from stepping forward to clinical applications. In this study, using our bioinspired polydopamine-laced hydroxyapatite collagen calcium silicate material as a representative of polydopamine-functionalized tissue engineering scaffolds, we discovered that polydopamine can be metabolized to dopamine specifically by osteoclasts, which we termed "osteoclast-driven polydopamine-to-dopamine release". The released dopamine showed an osteoinductive effect in vitro and promoted bone regeneration in calvarial critical-sized defects. The concept of "osteoclast-driven polydopamine-to-dopamine release" has considerable application potential. It could be easily adopted by other existing polydopamine-functionalized scaffolds: just by recruiting osteoclasts. Once adopted, scaffolds will obtain a dopamine-releasing function, which enables their modulation of osteoblast activity and hence elevates the osteoinductive effect. Thus, "osteoclast-driven polydopamine-to-dopamine release" serves as an upgrade patch, which is useful for many existing polydopamine-functionalized materials. [ABSTRACT FROM AUTHOR]

An appropriate skin tissue‐engineered scaffold can act promptly to combat microbial infection and preserve the wound throughout all phases of healing. To achieve sufficient healing, scaffolds should also promote cell proliferation and regeneration. Therefore, it has become essential to develop skin tissue engineering scaffolds that mimic the extracellular matrices of the skin, provide a high porosity scaffold structure, and act as an antimicrobial protection during wound healing. In this study, the polycaprolactone (PCL) electrospun scaffold was modified with optimal amounts of zinc oxide nanoparticles (ZnO) and Equisetum arvense (EA) herbal extract for potential application as antibacterial and wound healing scaffolds. Full characterization was carried out for fabricated scaffolds before in‐vitro assessments. FTIR spectroscopy and SEM images verified the successful substitution of nanofibers with EA and ZnO. These substitutions increased the hydrophilicity compared to the PCL scaffold. According to the results, the PCL/ZnO/EA fabricated scaffold was hemocompatible and non‐cytotoxic, in addition to allowing proper cell attachment. Effective antibacterial efficiency against Gram‐positive and Gram‐negative bacteria was also observed in this sample. Finally, the in vitro wound healing assay indicated that the addition of ZnO and EA improves the wound healing capacity of the scaffolds. The results indicate the potential of the developed scaffolds to prevent wound contamination and the complications of chronic infection. Highlights: Optimal concentrations of zinc oxide nanoparticles (ZnO) and Equisetum arvense (EA) were incorporated into electrospun polycaprolactone (PCL) nanofibers for potential wound dressing applications.The fabricated nanofibrous wound dressings offer a multitude of structural features in biomaterials.PCL fibers enable the controlled release of both ZnO and EA.The fabricated scaffolds exhibit favorable antibacterial, and antioxidant properties while maintaining biocompatibility and hemocompatibility. [ABSTRACT FROM AUTHOR]

A significant obstacle in bone tissue engineering is the creation of biodegradable bone replacements with the requisite mechanical and biological capabilities to treat more severe and intricately shaped injuries. Baghdadite has recently indicated that active biological ions such as silicon (Si4+) and zirconium (Zr4+) have been proven to increase bone growth considerably. In this study, we produced 3D-printed PCL-based scaffolds containing different amounts of Baghdadite using the robocasting solvent technique. Notably, PCL with 40 and 60 wt.% Baghdadite scaffolds (PB40 and PB60) promoted a more biomimetic environment for in vitro bone growth as their proper bioactivity and cell viability results were obtained without the addition of osteoinductive components. The printing process produced 3D scaffolds with a compressive strength of 7.94 MPa and elastic modulus of 29.95 MPa in PB40. According to the analytical prediction models in PB40, the elastic modulus was 24.7 and 26.89 MPa. Also, adding 60 wt.% Baghdadite increased the degradation rate to 5.1% in two months, more than six times that of PCL-based scaffolds. Cell proliferation assay demonstrated that the optical density of MG63 cells after 7 days of culture increased from 1.43 ± 0.03 to 1.82 ± 0.20 in PB40 as compared to pure PCL scaffold. Furthermore, bioactivity evaluation, ion release assessment, and morphological observation results further revealed that incorporating Baghdadite into a 3D-printed PCL-based scaffold could improve bone regeneration. Our findings demonstrate that the PCL/Baghdadite composite scaffold may be efficiently manufactured using 3D-printing technology and is extremely promising for bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

Conventional methods have failed to show the ability of articular cartilage to completely restore. Decellularized extracellular matrix has achieved interest as a potential biomaterial for cartilage tissue engineering approaches. The decellularized cartilage-derived matrix (CDM) scaffolds retain the native composition of cartilage tissue, providing a conducive microenvironment for cellular growth and differentiation, while exhibit limited mechanical support. Our investigation involved the fabrication of a new hybrid CDM- polyvinyl alcohol (PVA) hydrogel scaffold with four different concentrations (5%, 10%, 15%, and 20%), followed by a comprehensive characterization of the construct's physicochemical, mechanical, and biological properties to elucidate their potential in cartilage regeneration applications. Our results demonstrated that hybridization of the CDM with PVA enhanced the mechanical properties besides ensuring biocompatibility. FTIR and DSC results also confirmed the mechanical improvements in hybrid scaffolds. The hybrid CDM/PVA (15%/5%, 15%/10%, 15%/15%, and 15%/20%) scaffolds showed significantly different compressive strengths (p < 0.0001, p < 0.0004, p < 0.0001, p < 0.012 respectively). Moreover, resazurin test showed cell attachment and growth on all four types of hybrid scaffolds during seven days of three dimensional culture. The cross-linked CDM15%/PVA5% group, demonstrated acceptable mechanical strength, pore size, physicochemical properties, swelling behavior, and cell growth and attachment. Our data indicate that our hybrid CDM/PVA scaffold possess bioactive properties suitable for a promising candidate for cartilage tissue engineering studies. [ABSTRACT FROM AUTHOR]

Underlying complications constitute a significant factor contributing to the damage of blood vessel tissue. Tissue engineering is, therefore, essential for comprehending the various solutions to regenerate impaired tissue. Clinical applications have shown promising results in animal and human trials, but challenges remain in scaling production to achieve long-term success. Methods to gradually regenerate blood vessel tissue consist of synthetic polymer scaffolds, cell sheet assembly, natural protein scaffolds, and decellularized and recellularized matrices. Despite current progress, several limitations and challenges must be addressed, such as biocompatibility, immunogenicity, vascularization, cell source, and cell differentiation: continued research and innovative approaches toward tissue engineering hold great potential for transforming and improving patient outcomes. Overall, this review aims to establish a concrete understanding of the various approaches in vascular tissue engineering. [ABSTRACT FROM AUTHOR]

Tissues and organs contain an extracellular matrix (ECM). In the case of blood vessels, endothelium cells are anchored to a specialized basement membrane (BM) embedded inside the interstitial matrix (IM). We introduce a multi-structural collagen-based scaffold with embedded microchannels that mimics in vivo structures within vessels. Our scaffold consists of two parts, each containing two collagen layers, i.e., a 3D porous collagen layer analogous to IM lined with a thin 2D collagen film resembling the BM. Enclosed microchannels were fabricated using contact microprinting. Microchannel test structures with different sizes ranging from 300 to 800 µm were examined for their fabrication reproducibility. The heights and perimeters of the fabricated microchannels were ~20% less than their corresponding values in the replication PDMS mold; however, microchannel widths were significantly closer to their replica dimensions. The stiffness, permeability, and pore size properties of the 2D and 3D collagen layers were measured. The permeability of the 2D collagen film was negligible, making it suitable for mimicking the BM of large blood vessels. A leakage test at various volumetric flow rates applied to the microchannels showed no discharge, thereby verifying the reliability of the proposed integrated 2D/3D collagen parts and the contact printing method used for bonding them in the scaffold. In the future, multi-cell culturing will be performed within the 3D porous collagen and against the 2D membrane inside the microchannel, hence preparing this scaffold for studying a variety of blood vessel–tissue interfaces. Also, thicker collagen scaffold tissues will be fabricated by stacking several layers of the proposed scaffold. [ABSTRACT FROM AUTHOR]

Tissue engineered scaffolds aimed at the repair of critical‐sized bone defects lack adequate consideration for our aging society. Establishing an effective aged in vitro model that translates to animals is a significant unmet challenge. The in vivo aged environment is complex and highly nuanced, making it difficult to model in the context of bone repair. In this work, 3D nanofibrous scaffolds generated by the thermally‐induced self‐agglomeration (TISA) technique were functionalized with polydopamine nanoparticles (PD NPs) as a tool to improve drug binding capacity and scavenge reactive oxygen species (ROS), an excessive build‐up that dampens the healing process in aged tissues. PD NPs were reduced by ascorbic acid (rPD) to further improve hydrogen peroxide (H2O2) scavenging capabilities, where we hypothesized that these functionalized scaffolds could rescue ROS‐affected osteoblastic differentiation in vitro and improve new bone formation in an aged mouse model. rPDs demonstrated improved H2O2 scavenging activity compared to neat PD NPs, although both NP groups rescued the alkaline phosphatase activity (ALP) of MC3T3‐E1 cells in presence of H2O2. Additionally, BMP2‐induced osteogenic differentiation, both ALP and mineralization, was significantly improved in the presence of PD or rPD NPs on TISA scaffolds. While in vitro data showed favorable results aimed at improving osteogenic differentiation by PD or rPD NPs, in vivo studies did not note similar improvements in ectopic bone formation an aged model, suggesting that further nuance in material design is required to effectively translate to improved in vivo results in aged animal models. [ABSTRACT FROM AUTHOR]

Background: With the rapid growth of the ageing population, chronic diseases such as osteoarthritis have become one of the major diseases affecting the quality of life of elderly people. The main pathological manifestation of osteoarthritis is articular cartilage damage. Alleviating and repairing damaged cartilage has always been a challenge. The application of cartilage tissue engineering methods has shown promise for articular cartilage repair. Many studies have used cartilage tissue engineering methods to repair damaged cartilage and obtained good results, but these methods still cannot be used clinically. Therefore, this study aimed to investigate the effect of incorporating nerve growth factor (NGF) into a silk fibroin (SF)/chitosan (CS) scaffold containing bone marrow-derived mesenchymal stem cells (BMSCs) on the repair of articular cartilage defects in the knees of rabbits and to explore the possible underlying mechanism involved. Materials and methods: Nerve growth factor-loaded sustained-release microspheres were prepared by a double emulsion solvent evaporation method. SF/CS scaffolds were prepared by vacuum drying and chemical crosslinking. BMSCs were isolated and cultured by density gradient centrifugation and adherent culture. NGF-SF/CS-BMSC composites were prepared and implanted into articular cartilage defects in the knees of rabbits. The repair of articular cartilage was assessed by gross observation, imaging and histological staining at different time points after surgery. The repair effect was evaluated by the International Cartilage Repair Society (ICRS) score and a modified Wakitani score. In vitro experiments were also performed to observe the effect of different concentrations of NGF on the proliferation and directional differentiation of BMSCs on the SF/CS scaffold. Results: In the repair of cartilage defects in rabbit knees, NGF-SF/CS-BMSCs resulted in higher ICRS scores and lower modified Wakitani scores. The in vitro results showed that there was no significant correlation between the proliferation of BMSCs and the addition of different concentrations of NGF. Additionally, there was no significant difference in the protein and mRNA expression of COL2a1 and ACAN between the groups after the addition of different concentrations of NGF. Conclusion: NGF-SF/CS-BMSCs improved the repair of articular cartilage defects in the knees of rabbits. This repair effect may be related to the early promotion of subchondral bone repair. [ABSTRACT FROM AUTHOR]

Collagen is one main component of the extracellular matrix (ECM) in natural tissues and is, therefore, well suited as a biomaterial for tissue engineering. In this study, a method is presented to 3D‐bioprint collagen into a precipitation bath comprising recombinantly produced spider silk protein eADF4(C16) yielding a composite with excellent mechanical properties. The spider silk precipitation bath induced assembly of the collagen into fibrils, and subsequent addition of potassium phosphate buffer lead to the formation of silk particles and stabilization of the collagen fibrils. The produced collagen‐silk composite scaffolds show an internal structure of homogeneously distributed and interacting collagen fibrils and spider silk particles with significantly better mechanical properties compared to plain collagen scaffolds. Further, enzymatic degradation assays of the scaffolds over a 7‐day period show higher stability of the collagen‐silk scaffolds compared to plain collagen scaffolds in the presence of wound proteases. Using the spider silk variant eADF4(C16‐RGD) further increases compressive stress and elastic modulus compared to that of the unmodified variant. Finally, it is shown that the unique collagen‐spider silk composite scaffolds comprising the cell‐binding domains of collagen and the RGD sequence in the spider silk variant represent a promising material for soft tissue regeneration. [ABSTRACT FROM AUTHOR]

The regeneration of bone tissue is a complex process requiring innovative biomaterials with enhanced osteogenic properties to facilitate successful tissue engineering. Herein, a 3D bionic scaffold comprised of covalently bound graphene/carbon nanotube monoliths are present (3DGp/CNTs) exhibiting long‐range ordered porous characteristics, showcasing promising attributes for bone tissue applications. The lightweight, all‐carbon scaffolds not only demonstrate excellent mechanical performance in the hydrated state but also mimic the structural and functional features of the extracellular matrix, actively promoting cellular adhesion, proliferation, and differentiation. Significantly, the osteogenic differentiation of dental pulp stem cells (DPSCs) is observed, as evidenced by the upregulation of RUNX2, OSX, BSP, ALP, OPN, and OCN expression. This notable outcome can be attributed to the synergistic effect of 3DGp/CNTs, which create a conducive microenvironment for DPSCs and promote osteogenic differentiation by activating the BMP pathway. This observation elucidates the mechanism through which 3DGp/CNTs induce DPSC mineralization. The combination of these advantages, along with its straightforward and cost‐effective preparation technique, positions 3DGp/CNTs as a promising candidate for dental clinical engineering. [ABSTRACT FROM AUTHOR]

The biophysical heterogeneity of the bone–cartilage interface requires complex materials to mimic differences in bone density, extracellular matrix composition, and mineralization. Biomaterial approaches to repair osteochondral tissue typically use multilayer scaffolds, which require multistep fabrication and may undergo delamination at the construct interface. This work describes the development of functionalized microgels for the repair of osteochondral tissues using an N‐cadherin peptide, bone morphogenetic protein‐2 (BMP‐2) peptide, and changes in stiffness to create pro‐osteogenic and prochondrogenic microgels. Microgels, when annealed into a scaffold, outperforms bulk hydrogel controls evidenced by upregulation of osteogenic and chondrogenic markers in mesenchymal stromal cells (MSCs). The macroporous void space present in microgel anneals scaffolds enabled robust cell proliferation and extracellular matrix (ECM) deposition throughout the entire scaffold. A bilayer functionalized annealed microgel scaffold is then created and the ability to spatially control the differentiation of MSCs is assessed. Osteochondral bilayer scaffolds exhibit distinct regions of osteogenic and chondrogenic protein expression as a function of microgel population upon immunostaining for osteocalcin and aggrecan, respectively. Spatial transcriptomics confirm osteogenic and chondrogenic genes are upregulated in their respective microgel regions. These studies highlight the tunable and functionalizable nature of microgels and the importance of macroporous void space. [ABSTRACT FROM AUTHOR]

Liver cancer, characterized as a kind of malignant tumor within the digestive system, poses great health harm, and immune escape stands out as an important reason for its occurrence and development. Chemokines, pivotal in guiding immune cells' migration, is necessary to initiate and deliver an effective anti-tumor immune response. Therefore, understanding the chemotactic environment and identifying chemokines that regulate recruitment of immune cells to the tumor microenvironment (TME) are critical to improve current immunotherapy interventions. Herein, we report a well-defined inverse opal scaffold generated with a microfluidic emulsion template for the construction of a vascularized liver tumor model, offering insights into immune cells' recruitment. Due to the excellent 3D porous morphology of the inverse opal scaffold, human hepatocellular carcinoma cells can aggregate in the pores of the scaffold to form uniform multicellular tumor spheroids. More attractively, the vascularized liver tumor model can be achieved by constructing a 3D co-culture system involving endothelial cells and hepatocellular carcinoma cells. The results demonstrate that the 3D co-cultured tumor cells increase the neutrophil chemokines remarkably and recruit neutrophils to tumor tissues, then promote tumor progression. This approach opens a feasible avenue for realizing a vascularized liver tumor model with a reliable immune microenvironment close to that of a solid tumor of liver cancer. [ABSTRACT FROM AUTHOR]

Advancements in new treatment methods are becoming increasingly necessary due to a longer life expectancy, particularly in the field of osteochondral tissue engineering. In the present study, osteochondral tissue scaffolds with/without the addition of hawthorn or elderberry extracts were fabricated. Poly(ethylene glycol) diglycidyl ether (PEGDE) cross‐linked carboxymethyl chitosan hydrogel scaffold matrix was used as a control group. The addition of the plant extracts resulted in open porous structures with pore sizes around 100–450 μm and elastic modulus between 0.5 and 0.7 MPa, biomimicking the osteochondral tissue. Scaffolds containing either plant extract showed a high swelling tendency (1500–1750%) and a delayed release of the extracts after a week. Furthermore, the weight loss of the scaffolds after an enzymatic degradation for 56 days was ~30%. In addition, in vitro biocompatibility analyses were performed using bone marrow‐derived mesenchymal stem cells confirming non‐cytotoxicity for all the scaffold types. Biochemical assessment of alkaline phosphatase activity and glycosaminoglycan content yielded results consistent with osteochondral scaffold requirements. Finally, immunohistochemical analyses indicated that the plant extract addition, especially elderberry, increased collagen type I and type II formation. As a result, the addition of both hawthorn and elderberry extracts is a promising approach to osteochondral tissue regeneration. [ABSTRACT FROM AUTHOR]

Articular cartilage regeneration is a challenge in tissue engineering. Although diverse materials have been developed for this purpose, cartilage regeneration remains suboptimal. The integration of nanomaterials into 3D network materials holds great potential in the improvement of key mechanical properties, particularly important for osteochondral replacement scaffolds and even to function as carriers for disease‐modifying drugs or other regulatory signals. In this study, a simple yet effective cell‐free nanoenabled Col‐PLA scaffold specially designed to enhance cartilage regeneration and modulate inflammatory response is proposed, by incorporating poly(lactic‐co‐glycolic acid) (PLGA) ibuprofen nanoparticles (NPs) into a collagen/polylactide (Col‐PLA) matrix. The developed nanoenabled scaffold successfully decreases IL‐1β release and leads to primary human chondrocytes survival, ultimately restoring extracellular matrix (ECM) production under inflammatory conditions. The nanoenabled Col‐PLA scaffolds secretome effectively decreases macrophage invasion in vitro, as well as neutrophil infiltration and inflammatory mediators', namely the complement component C5/C5a, C‐reactive protein, IL‐1β, MMP9, CCL20, and CXCL1/KC production in vivo in a rodent air‐pouch model. Overall, the established nanoenabled scaffold has the potential to support chondrogenesis as well as modulate inflammatory response, overcoming the limitations of traditional tissue engineering strategies. [ABSTRACT FROM AUTHOR]

Silk fibroin hydrogels are extensively explored for tissue engineering and regenerative medicine as an artificial extracellular matrix (ECM) that can support tissue growth. However, the nanometer pore size of hydrogels limits adequate cell, tissue, and vascular infiltration. Microgel scaffolds are an emerging class of microporous biomaterials formed by annealing small microscale hydrogels (microgels) into a 3D construct. In this work, silk microgels are generated using a microfluidic device that allows tuning of the microgel diameter (100–400 µm) and are stabilized via visible light‐initiated photo‐crosslinking of native tyrosine residues in silk. Microgels are then covalently annealed using silk solution as glue and the same cytocompatible visible light‐initiated crosslinking to form microgel scaffolds. Unlike the nano‐porosity of bulk photo‐crosslinked silk hydrogels, the microgel scaffolds have an average pore diameter of 29 ± 17 or 192 ± 81 µm depending on the microgel size, with enhanced mechanical properties compared to bulk hydrogels. This microporosity supports enhanced cell spreading and proliferation in vitro and increases scaffold remodeling in vivo, encouraging improved tissue infiltration and matrix deposition. The microgel size and material format also affect inflammatory responses in vivo. This work demonstrates that silk microgels and microgel scaffolds are promising candidates for tissue engineering and regenerative medicine applications. [ABSTRACT FROM AUTHOR]

In recent years, people have had more expectations from the developed technology in medicine, especially in the field of orthopedics and traumatology. Tissue engineers are interested in techniques that benefit from patients' cells and biomaterials, instead of prostheses and implants. On the other hand, researchers have begun to use various medicinal plants for regeneration and anti-cancer studies. In the present study, we aimed to produce cartilage and bone inductive scaffolds for osteochondral tissue engineering applications with the addition of hawthorn or elderberry extracts. Firstly, wet electro-spun poly (3-hydroxybutyric acid-co-3-hydroxyvaleric acid) fibers were integrated with a loofah mat. Then, they were impregnated into chitosan solution with/without hawthorn or elderberry extract. Composite hydrogel scaffolds were obtained by cross-linking with 0.3% (w/v) genipin. Fabricated scaffolds had more than 90% porosity and showed swelling capacity in the range of 1500–2200%. Based on the in vitro biocompatibility analyses using mesenchymal stem cells (MSCs), all the fabricated scaffolds were found to be biocompatible by WST-1, ALP activity, and GAG content analysis. Also, histological/immunohistochemical analyses showed that hawthorn and elderberry extract addition increased MSCs proliferation and collagen type I and II positivity. Consequently, all the scaffolds showed promising features for osteochondral tissue engineering applications. [ABSTRACT FROM AUTHOR]

Decellularization of plant tissues is an emerging route to fabricate scaffolds for tissue engineering and regenerative medicine. Although significant progress has been made in the field of plant tissue decellularization, functionalization of plant scaffolds is still an emerging field, and loading them with L-ascorbic acid to promote skin regeneration has not yet been reported. L-ascorbic acid is an antioxidant that plays a key role in collagen synthesis as a cofactor of lysyl hydroxylase and prolyl hydroxylase. It has been shown to have significant importance in physiological wound healing by stimulating fibroblasts to produce collagen at both the molecular and the genetic levels. In this work, we aimed to fabricate an ascorbic acid-releasing bioactive scaffold by introducing a stable form of ascorbic acid, L-ascorbic acid 2-phosphate (AA2P), into decellularized baby spinach leaves and investigated its biological activity in vitro. Our results demonstrated that AA2P could be easily introduced into decellularized baby spinach leaf scaffolds and subsequently released within the effective dose range. AA2P-releasing baby spinach leaves were found to increase metabolic activity and enhance collagen synthesis in L929 fibroblasts after 21 days. In conclusion, this study demonstrated the fabrication of a novel functionalized skin tissue engineering scaffold and made a significant contribution to the fields of plant decellularization and skin tissue engineering. [ABSTRACT FROM AUTHOR]

Advanced therapeutic dressings are the current research interest that achieves rapid and complete wound healing. The healing of skin wounds demonstrates a remarkable cellular function process that is distinct in nature and involves the interaction of various cells, growth factors, and cytokines. In this study, nanofibrous scaffolds were prepared using poly(ε-caprolactone) and polylactic acid as mat scaffolds. Also, copper nanoparticles (CuNPs) and curcumin were added to fabricate a hybrid nanocomposite scaffold using the electrospinning technique. The fabricated scaffolds were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), tensile analysis, porosity, and water vapor transmission rate. SEM analysis proved the nanostructured fibers have suitable porosity without any beads. The presence of CuNPs in the PCL-Cu nanofibrous mat was confirmed by TEM analysis. The tensile test confirmed an increase and decrease in the elongation ratio by CuNPs and curcumin addition, respectively. The biocompatibility and cell attachment to the nanofibers were proved by MTT and DAPI staining which proved a significantly positive effect of curcumin in the cell growth. The scaffold can hinder both the gram-negative and gram-positive bacteria through direct contact with them. This research study showed that the addition of CuNPs and curcumin in the hybrid nanocomposite scaffold compensates for each other's shortcomings and has the potential to be used in wound healing applications. [ABSTRACT FROM AUTHOR]

Skin injuries are common problems and large skin defects or infected skin needs extra attention that make the researchers find new solutions. Herein, a novel biocompatible, biodegradable antibacterial scaffold containing gelatin, TiO2, polycaprolactone, and silk fibroin loaded with different ratios of curcumin (0.5, 1, and 1.5% wt.) was fabricated with electrospinning technique and was tested with various in vitro tests. The cellular investigations (cell adhesion, cell viability, and in vitro migration test) and antibacterial assay revealed the higher efficiency of the scaffold with 1% wt. curcumin and further investigation were performed on this scaffold. The morphological observation confirmed the nanofibrous structure of the scaffold, with 0.10 ± 0.015 μm average fiber diameter. This scaffold showed hydrophilic nature with high swelling ratio absorption and 76.45 ± 5.19% degradation ratio after 2 weeks. Also, it could provide adequate mechanical properties for skin regeneration. The drug-releasing investigation revealed Cur's controlled release over 48 h. Therefore, this biocompatible and antibacterial scaffold showed high potential for treating skin injuries and is suggested for future in vivo studies. [ABSTRACT FROM AUTHOR]

Hydrogel skin grafts provide a moist environment and act as a regenerative template to the newly formed tissue. In this study, we developed 3D-bio-printed hydrogels using methacrylated pectin and methacrylated gelatin together with an antibacterial agent (curcumin), a bioactive agent (Vitamin-C) and fibroblast cells. Curcumin release was almost 10 times higher at pH 7.4 than pH 5.0, and it demonstrated antimicrobial affinity against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The developed 3D-bio-printed hydrogels containing cells and bioactive agents demonstrated high cell viability, cell proliferation, and collagen production, and are promising skin graft candidates for the treatment of full-thickness problematic wounds. [ABSTRACT FROM AUTHOR]

Tissue engineering applications in bone defect treatment have shown promising outcomes over the past decade. In this context, taking advantage of bioactive scaffolds mimicking the intrinsic composition of bone has resulted in remarkable effects on bone regeneration. In this study, Zirconium-based metal-organic framework, known as MOF 801, was synthesized and incorporated into the gelatin matrix as an osteoconductive agent to fabricate a nanocomposite bone scaffold by freeze-drying method. Physical and chemical characteristics of MOF 801 and nanocomposite scaffolds were analyzed using FE-SEM, EDS, XRD, ICP and FTIR. Besides, the biological activity of the prepared scaffolds was evaluated by MTT, alizarin red staining, crystal violet staining, and ALP assays. Inclusion of MOF 801 NPs into the scaffolds resulted in enhancement of their compressive strength up to 15 ± 0.05 MPa. The nanocomposite samples containing MOF 801 NPs also exhibited favorable bioactive feature that was confirmed by their apatite-forming ability on their surfaces upon immersion in SBF solution. The Zr ion and fumarate release studies illustrated sustained release profiles from the gelatin matrix, leading to both antioxidant and anti-inflammatory properties. MTT assay results affirmed biocompatibility of scaffolds containing up to 5 % w/w MOF 801, besides the crystal violet assay exhibited proper cell confluency and adhesion. Eventually, Alizarin red and ALP activity assays revealed that an increment of MOF 801 could induce calcium mineralization and Alkaline Phosphatase enzyme production in MG-63 cells confirming the potential of prepared scaffolds for related bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

Self-assembling peptide-based hydrogels have become a highly attractive scaffold for three-dimensional (3D) in vitro disease modeling as they provide a way to create tunable matrices that can resemble the extracellular matrix (ECM) of various microenvironments. Alzheimer's disease (AD) is an exceptionally complex neurodegenerative condition; however, our understanding has advanced due to the transition from two-dimensional (2D) to 3D in vitro modeling. Nonetheless, there is a current gap in knowledge regarding the role of amyloid structures, and previously developed models found long-term difficulty in creating an appropriate model involving the ECM and amyloid aggregates. In this report, we propose a multi-component self-assembling peptide-based hydrogel scaffold to mimic the amyloid-beta (β) containing microenvironment. Characterization of the amyloid-β-mimicking hydrogel (Col-HAMA-FF) reveals the formation of β-sheet structures as a result of the self-assembling properties of phenylalanine (Phe, F) through π−π stacking of the residues, thus mimicking the amyloid-β protein nanostructures. We investigated the effect of the amyloid-β-mimicking microenvironment on healthy neuronal progenitor cells (NPCs) compared to a natural-mimicking matrix (Col-HAMA). Our results demonstrated higher levels of neuroinflammation and apoptosis markers when NPCs were cultured in the amyloid-like matrix compared to a natural brain matrix. Here, we provided insights into the impact of amyloid-like structures on NPC phenotypes and behaviors. This foundational work, before progressing to more complex plaque models, provides a promising scaffold for future investigations on AD mechanisms and drug testing. In this study, we engineered two multi-component hydrogels: one to mimic the natural extracellular matrix (ECM) of the brain and one to resemble an amyloid-like microenvironment using a self-assembling peptide hydrogel. The self-assembling peptide mimics β-amyloid fibrils seen in amyloid-β protein aggregates. We report on the culture of neuronal progenitor cells within the amyloid-mimicking ECM scaffold to study the impact through marker expressions related to inflammation and DNA damage. This foundational work, before progressing to more complex plaque models, offers a promising scaffold for future investigations on AD mechanisms and drug testing. [Display omitted] [ABSTRACT FROM AUTHOR]

Scaffolds play a key role in cultured meat production by providing an optimal environment for efficient cell attachment, growth, and development. This study investigated the effects of gelatin coating on the adhesion, proliferation, and adipogenic differentiation of adipose tissue-derived stem cells (ADSCs) cultured on soy protein–agarose scaffolds. Gelatin-coated scaffolds were prepared using 0.5% and 1.0% (w/v) gelatin solutions. The microstructure, water absorption rate, mechanical strength, cytotoxicity, cell adhesion, proliferation, and differentiation capabilities of the scaffolds were analyzed. Field emission scanning electron microscopy revealed the porous microstructure of the scaffolds, which was suitable for cell growth. Gelatin-coated scaffolds exhibited a significantly higher water absorption rate than that of non-coated scaffolds, indicating increased hydrophilicity. In addition, gelatin coating increased the mechanical strength of the scaffolds. Gelatin coating did not show cytotoxicity but significantly enhanced cell adhesion and proliferation. The gene expression levels of peroxisome proliferator-activated receptor gamma, CCAT/enhancer-binding protein alpha, and fatty acid-binding protein 4 were upregulated, and lipid accumulation was increased by gelatin coating. These findings suggest that gelatin-coated scaffolds provide a supportive microenvironment for ADSC growth and differentiation, highlighting their potential as a strategy for the improvement of cultured meat production and adipose tissue engineering. [ABSTRACT FROM AUTHOR]

As a 3D rapid prototyping technology, 3D printing (3DP) technology has been widely applied in medical research, fabricating various medical devices or implants. With the development of biomaterials and cell‐related technologies, 3DP, especially bioprinting technology, is quietly bringing great changes and opportunities in the medical industry. Beyond surgical models, medical devices, and implants, traditional 3DP, cell‐based 3D bioprinting, and emerging 4D printing (4DP) have significantly aided in the advancement and manufacture of pharmaceuticals and biological alternatives for tissue engineering. It is envisioned that future healthcare systems, based on evolving 3DP technology and precision medicine, will deliver customized solutions that cater to the unique differences and needs of each patient. In this review work, several mainstream 3D bioprinting technologies are presented, with a focus on recent advances in 3DP for pharmaceutical engineering and important tissue engineering, including vascular and bone tissue engineering. Challenges and future prospects of 3DP for drug discovery, drug delivery systems, artificial blood vessels, vascular and bone tissue engineering scaffolds, and practical applications are also covered. Finally, the differences between 3DP and 4DP, as well as the advantages and disadvantages of different stimulus response mechanisms in 4DP and their potential applications are summarized. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this study, hydroxyapatite (HAp)/mineralized collagen hydrogel composites were prepared by incorporating different amounts of dopamine‐modified HAp particles during the process of collagen self‐assembly and simultaneous mineralization. Zeta potential results showed that the surface charge of modified HAp particles was altered, and scanning electron microscopy patterns indicated that HAp particles were uniformly distributed in the hydrogels. The occurrence of collagen biomineralization was indirectly reflected by the results of Ca and P content in the hydrogel supernatant, and the results of ash content indicated that the mineral content of the hydrogels could be up to 60% or more, which was close to the inorganic content in natural bone. The results of CCK‐8 and ALP activity assays showed that mineralized collagen hydrogels were favorable for cell proliferation and differentiation, and the hydrogels containing dopamine‐modified HAp particles obtained a higher expression of osteogenic differentiation related transcription factor. The results showed that the excellent adhesion properties of dopamine contributed to enhance the bone repair potential of the composites, suggesting that mineralized collagen hydrogel composites containing dopamine‐modified HAp particles, which could mimic the structure and composition of bone, have a promising potential as bone tissue engineering scaffolds. [ABSTRACT FROM AUTHOR]

Adipose tissues, particularly beige and brown adipose tissue, play crucial roles in energy metabolism. Brown adipose tissues' thermogenic capacity and the appearance of beige cells within white adipose tissue have spurred interest in their metabolic impact and therapeutic potential. Brown and beige fat cells, activated by environmental factors like cold exposure or by pharmacology, share metabolic mechanisms that drive non-shivering thermogenesis. Understanding these two cell types requires advanced, yet broadly applicable in vitro models that reflect the complex microenvironment and vasculature of adipose tissues. Here we present mouse vascularized adipose spheroids of the stromal vascular microenvironment from inguinal white adipose tissue, a tissue with 'beiging' capacity in mice and humans. We show that adding a scaffold improves vascular sprouting, enhances spheroid growth, and upregulates adipogenic markers, thus reflecting increased adipocyte maturity. Transcriptional profiling via RNA sequencing revealed distinct metabolic pathways upregulated in our vascularized adipose spheroids, with increased expression of genes involved in glucose metabolism, lipid metabolism, and thermogenesis. Functional assessment demonstrated increased oxygen consumption in vascularized adipose spheroids compared to classical 2D cultures, which was enhanced by β-adrenergic receptor stimulation correlating with elevated b-adrenergic receptor expression. Moreover, stimulation with the naturally occurring adipokine, FGF21, induced Ucp1 mRNA expression in the vascularized adipose spheroids. In conclusion, vascularized inguinal white adipose tissue spheroids provide a physiologically relevant platform to study how the stromal vascular microenvironment shapes adipocyte responses and influence activated thermogenesis in beige adipocytes. [ABSTRACT FROM AUTHOR]

Previously, we reported successful cellular expansion of a murine colorectal carcinoma cell line (CT-26) using a three-dimensional (3D) engineered extracellular matrix (EECM) fibrillar scaffold structure. CCL-247 were grown over a limited time period of 8 days on 3D EECM or tissue culture polystyrene (TCPS). Cells were then assayed for growth, electroporation efficiency and Vigil manufacturing release criteria. Using EECM scaffolds, we report an expansion of CCL-247 (HCT116), a colorectal carcinoma cell line, from a starting concentration of 2.45 × 105 cells to 1.9 × 106 cells per scaffold. Following expansion, 3D EECM-derived cells were assessed based on clinical release criteria of the Vigil manufacturing process utilized for Phase IIb trial operation with the FDA. 3D EECM-derived cells passed all Vigil manufacturing release criteria including cytokine expression. Here, we demonstrate successful Vigil product manufacture achieving the specifications necessary for the clinical trial product release of Vigil treatment. Our results confirm that 3D EECM can be utilized for the expansion of human cancer cell CCL-247, justifying further clinical development involving human tissue sample manufacturing including core needle biopsy and minimal ascites samples. [ABSTRACT FROM AUTHOR]

Spinal cord injury (SCI) represents a profound central nervous system affliction, resulting in irreversibly compromised daily activities and disabilities. SCI involves excessive inflammatory responses, which are characterized by the existence of high levels of proinflammatory M1 macrophages, and neuronal mitochondrial energy deficit, exacerbating secondary damage and impeding axon regeneration. This study delves into the mechanistic intricacies of SCI, offering insights from the perspectives of neuroimmune regulation and mitochondrial function, leading to a pro-fibrotic macrophage phenotype and energy-supplying deficit. To address these challenges, we developed a smart scaffold incorporating enzyme mimicry nanoparticle-ceriumoxide (COPs) into nanofibers (NS@COP), which aims to pioneer a targeted neuroimmune repair strategy, rescuing CGRP receptor on macrophage and concurrently remodeling mitochondrial function. Our findings indicate that the integrated COPs restore the responsiveness of pro-inflammatory macrophages to calcitonin gene-related peptide (CGRP) signal by up-regulating receptor activity modifying protein 1 (RAMP1), a vital component of the CGRP receptor. This promotes macrophage fate commitment to an anti-inflammatory pro-resolution M2 phenotype, then alleviating glial scar formation. In addition, NS@COP implantation also protected neuronal mitochondrial function. Collectively, our results suggest that the strategy of integrating nanozyme COP nanoparticles into a nanofiber scaffold provides a promising therapeutic candidate for spinal cord trauma via rational regulation of neuroimmune communication and mitochondrial function. [ABSTRACT FROM AUTHOR]

Electrospun nanofiber scaffolds mimic the structure of the natural extracellular matrix, making them promising for application in tissue engineering. Based on this, the biopolymers poly(ε-caprolactone) (PCL) and gelatin, with good mechanical and biological properties, respectively, were electrospun with acetic acid as the only solvent, without the crosslinking process in order to reduce the cytotoxic effects of commonly used solvents. This study evaluated the influence of scaffold thicknesses on the physicochemical properties. Scaffolds with 4 different thicknesses were produced by increasing the electrospinning time (A = 1 h, B = 1.5 h, C = 2 h and D = 3 h). Thicker scaffolds (B, C and D, 0.142 ± 0.029 to 0.306 ± 0.053 nm) were manipulated easily, presented higher mechanical strength (from 156.21 to 178.53%) and smaller diameter fibers (approximately 300.0 nm). On the other hand, the longer the processing time, the less uniform the fibers and more melting regions between fibers, which may hinder the use of the scaffold and should be considered. Only the thickest scaffold (D) showed higher wettability (contact angle 31.1° ± 3°). Intermediate thickness scaffolds showed less beads and fiber irregularities. Cell adhesion was good due to gelatin, though cell proliferation remained constant for the thicker scaffold indicating that longer processing time may not be advantageous for cell application. Results showed that intermediate thickness scaffolds of PCL/gelatin (0.142 ± 0.029 to 0.195 ± 0.034 nm) assure good physicochemical properties to be applied for different cell types. [ABSTRACT FROM AUTHOR]

Ice‐templated porous biomaterials possess transformative potential in regenerative medicine; yet, scaling up ice‐templating processes for broader applications—owing to inconsistent pore formation—remains challenging. This study reports an innovative semi‐solid freeze‐casting technique that draws inspiration from semi‐solid metal processing (SSMP) combined with ice cream‐production routines. This versatile approach allows for the large‐scale assembly of various materials, from polymers to inorganic particles, into isotropic 3D scaffolds featuring uniformly equiaxed pores throughout the centimeter scale. Through (cryo‐)electron microscopy, X‐ray tomography, and finite element modeling, the structural evolution of ice grains/pores is elucidated, demonstrating how the method increases the initial ice nucleus density by pre‐fabricating a semi‐frozen slurry, which facilitates a transition from columnar to equiaxed grain structures. For a practical demonstration, as‐prepared scaffolds are integrated into a bilayer tissue patch using biodegradable waterborne polyurethane (WPU) for large‐scale oral mucosal reconstruction in minipigs. Systematic analyses, including histology and RNA sequencing, prove that the patch modulates the healing process toward near‐scarless mucosal remodeling via innate and adaptive immunomodulation and activation of pro‐healing genes converging on matrix synthesis and epithelialization. This study not only advances the field of ice‐templating fabrication but sets a promising precedent for scaffold‐based large‐scale tissue regeneration. [ABSTRACT FROM AUTHOR]

In regenerative medicine, to create tissue equivalents of the skin, great importance is paid to the study of the biocompatibility of scaffolds and skin cell culture. In the current scientific work, the dynamics of fibroblast cell cycle parameters in the in vitro system were evaluated by flow cytofluorometry in two experimental models. The first model is to evaluate the biocompatibility of fibroblasts with scaffolds under 2D and 3D cultivation conditions. The second model is an assessment of the biology of fibroblasts after exposure to UV radiation. The fibroblasts necessary for the study were isolated and cultured using mechanical dissociation of the tissue. Cell lines of the third passage were used in the experiment. To study the effect of ultraviolet irradiation on the parameters of the fibroblast cell cycle in vitro culture, cell lines were irradiated with a UV lamp. To analyze the biocompatibility of the fibroblast cell line with scaffolds, fibroblasts were seeded on two types of carriers: "G-DERM" and "Transwell". It was found that for two weeks of cultivation, high cell biocompatibility was observed in the G-DERM scaffold under 2D cultivation conditions. UV irradiation causes the cell cycle to stop as a compensatory adaptive process in response to the action of damaging radiation. Temporary exposure and dose-dependent exposure to UV radiation for 30 seconds do not have a pronounced lethal effect on cell cultures. [ABSTRACT FROM AUTHOR]

This article presents ordered and systematized data obtained from modern literary sources devoted to the use of chitosan in tissue engineering. At the end of the article, data from our scientific research is presented, in which an attempt was made to create a threedimensional scaffold based on chitosan. Sterile scaffolds were subcutaneously sewn into the soft tissues of the withers area or in the area of artificial femoral defects of rats. The tissue sections together with the implants were removed 4 and 8 weeks after placement under the same conditions. When removing, the mobility of the regenerants in situ, the state of the surrounding fiber, the presence of vessels feeding the scaffold, the severity of the adhesive process, and the degree of biodegradation of the scaffolds were evaluated. In the field of bone defect replacement, attention was paid to the degree of osseointegration, the completeness of the closure of the defect, and the density of the regeneration. The analysis of modern world literature and the results of our experiments show that the main components of the innovative trend and the use of chitosan for tissue engineering of articular cartilage are: modification of chitosan scaffold by copolymerization with various organic compounds; improvement of methods for the preparation of three-dimensional biomimetic nanostructured chitosan scaffolds; intensification of the use of chitosan-based scaffolds in the process of creating them to improve their viscosity-strength, chondroinductive, and antibacterial properties of biologically active additives. [ABSTRACT FROM AUTHOR]

Background & Objectives: This study aimed to construct a decellularized mouse spleen scaffold and evaluate its cellular compatibility in vitro using murine bone marrow-derived mesenchymal stem cells (BM-MSCs). Materials & Methods: A combination of physical, chemical, and enzymatic treatments was employed for mouse spleen decellularization. These included multiple freezethaw cycles, the ionic detergent sodium dodecyl sulfate (SDS), and enzymatic trypsin. Histological and scanning electron microscopy analyses were conducted up to 7 days post-culture to assess the impact of decellularization and cellular adaptation to the spleen scaffolds. Results: Histological studies revealed the attachment and penetration of BM-MSCs into the scaffolds on days 5-7 following cell seeding. Furthermore, cell migration into the scaffold was observed 5 days after the seeding process. Conclusion: The decellularization approach utilized in this study proved to be effective and biocompatible, supporting the preservation and proliferation of BM-MSCs. These findings indicate its potential for spleen tissue engineering applications. [ABSTRACT FROM AUTHOR]