Scaffold System Research Articles

Injectable Photocrosslinked Hydrogel Dressing Encapsulating Quercetin-Loaded Zeolitic Imidazolate Framework-8 for Skin Wound Healing

Background: Wound management is a critical component of clinical practice. Promoting timely healing of wounds is essential for patient recovery. Traditional treatments have limited efficacy due to prolonged healing times, excessive inflammatory responses, and susceptibility to infection. Methods: In this research, we created an injectable hydrogel wound dressing formulated from gelatin methacryloyl (GelMA) that encapsulates quercetin-loaded zeolitic imidazolate framework-8 (Qu@ZIF-8) nanoparticles. Next, its ability to promote skin wound healing was validated through in vitro experiments and animal studies. Results: Research conducted both in vitro and in vivo indicated that this hydrogel dressing effectively mitigates inflammation, inhibits bacterial growth, and promotes angiogenesis and collagen synthesis, thus facilitating a safe and efficient healing process for wounds. Conclusions: This cutting-edge scaffold system provides a novel strategy for wound repair and demonstrates significant potential for clinical applications.

Mechanically enhanced biodegradable scaffold based on SF microfibers for repairing bone defects in the distal femur of rats

Silk-based biodegradable materials play an important role in tissue engineering, especially in the field of bone regeneration. However, while optimizing mechanical properties and bone regeneration characteristics, modified silk fibroin (SF)-based materials also increase the complexity of scaffold systems, which is not conducive to clinical translation. In this study, we first added synthetic biomimetic mineralized collagen (MC) particles to SF-based materials to improve the bone regeneration properties of the scaffolds and simultaneously regulated the degradation rate of the scaffolds to match the bone regeneration rate. Second, SF microfibers were prepared by hydrolysis with alkaline heating and added to SFMC scaffolds with excellent osteogenic stimulation ability to prepare SF microfiber (mf)-modified SFMC-mf scaffolds with excellent mechanical properties, whose compression modulus increased from 4.58±0.23 MPa to 14.63±0.88 MPa. Finally, the SFMC-mf scaffold was implanted into the weight-bearing bone defect area of the distal femur of rats, and the results showed that the SFMC-mf scaffold significantly promoted functional recovery of the affected limb and increased the amount of new bone in the defect area compared with those in the SFC-mf group and the blank control group. In addition, the RNA-seq results suggested that the genes with upregulated expression in the SFMC-mf scaffold group were mainly enriched in vascular regeneration. In conclusion, this SF microfiber modification method effectively improved the mechanical properties of SFMC scaffolds without moving the SF scaffold system in the direction of compositional complexity, providing new insights for the subsequent development of more effective bionic repair materials for bone defects and assisting in their clinical translation.

Sodium alginate hydrogels co-encapsulated with cell free fat extract-loaded core-shell nanofibers and menstrual blood stem cells derived exosomes for acceleration of articular cartilage regeneration

This study presents a novel scaffold system comprising sodium alginate hydrogels (SAh) co-encapsulated with cell-free fat extract (CEFFE)-loaded core-shell nanofibers (NFs) and menstrual blood stem cell-derived exosomes (EXOs). The scaffold integrates the regenerative potential of EXOs and CFFFE, offering a multifaceted strategy for promoting articular cartilage repair. Coaxially electrospun core-shell NFs exhibited successful encapsulation of CEFFE and seamless integration into the SAh matrix. Structural modifications induced by the incorporation of CEFFE-NFs enhanced hydrogel porosity, mechanical strength, and degradation kinetics, facilitating cell adhesion, proliferation, and tissue ingrowth. The release kinetics of growth factors from the composite scaffold demonstrated sustained and controlled release profiles, essential for optimal tissue regeneration. In vitro studies revealed high cell viability, enhanced chondrocyte proliferation, and migration in the presence of EXOs/CEFFE-NFs@SAh composite scaffolds. Additionally, in vivo experiments demonstrated significant cartilage regeneration, with the composite scaffold outperforming controls in promoting hyaline cartilage formation and defect bridging. Overall, this study underscores the potential of EXOs and CEFFE-NFs integrated into SAh matrices for enhancing chondrocyte viability, proliferation, migration, and ultimately, articular cartilage regeneration. Future research directions may focus on elucidating underlying mechanisms and conducting long-term in vivo studies to validate clinical applicability and scalability.

Design of a Genetically Programmable and Customizable Protein Scaffolding System for the Hierarchical Assembly of Robust, Functional Macroscale Materials.

Inspired by the properties of natural protein-based biomaterials, protein nanomaterials are increasingly designed with natural or engineered peptides or with protein building blocks. Few examples describe the design of functional protein-based materials for biotechnological applications that can be readily manufactured, are amenable to functionalization, and exhibit robust assembly properties for macroscale material formation. Here, we designed a protein-scaffolding system that self-assembles into robust, macroscale materials suitable for in vitro cell-free applications. By controlling the coexpression in Escherichia coli of self-assembling scaffold building blocks with and without modifications for covalent attachment of cross-linking cargo proteins, hybrid scaffolds with spatially organized conjugation sites are overproduced that can be readily isolated. Cargo proteins, including enzymes, are rapidly cross-linked onto scaffolds for the formation of functional materials. We show that these materials can be used for the in vitro operation of a coimmobilized two-enzyme reaction and that the protein material can be recovered and reused. We believe that this work will provide a versatile platform for the design and scalable production of functional materials with customizable properties and the robustness required for biotechnological applications.

Extracellular vesicle-laden hybrid cryogel-interpenetrating network scaffold for improved osteogenesis in bone tissue engineering

Bone tissue engineering (BTE) aims to regenerate the damaged or diseased bone by combining cells, growth factors, and biomaterials. Synthetic bone tissue, which is widely available, is a promising alternative to autografts, allografts, and natural fillers. Biomaterials like 3D scaffolds mimic the extracellular matrix, supporting cell growth and tissue regeneration. However, clinical applications face challenges such as limited osteogenic and angiogenic capabilities, weak mechanical strength, and risks of infection and immune reactions. The current work introduces a mechanically robust cryogel-hydrogel hybrid scaffold, loaded with extracellular vesicles (EVs) and cell secretomes as osteoinductive cues. The scaffold’s mechanical strength was assessed against its individual components. Its physical characteristics, including swelling capacity and porous structure, were analyzed using field emission scanning electron microscopy (FESEM), and the incorporation of nano-hydroxyapatite (nHAp) was confirmed through Fourier transform infrared (FTIR) spectroscopy. Three scaffolds were tested: a cryogel scaffold of gelatin and nano-hydroxyapatite (nHAp), a hydrogel scaffold of poly(ethylene glycol) diacrylate (PEGDA), and a hybrid cryogel scaffold of gelatin and nano-hydroxyapatite with a PEGDA interpenetrating network (IPN). The results indicated that the hybrid cryogel scaffold with IPN had the greatest normalized ALP content and lowest cytotoxicity, making it the best choice for further study. To explore the osteoinductive potential of Mesenchymal Stem Cell-derived EVs, three scaffold variations were tested: a hybrid IPN scaffold, IPN + nHAp scaffold, and IPN + nHAp + EVs scaffold. These were evaluated for viable cell count, ALP activity, DNA content, and calcium accumulation. The IPN + nHAp + EVs scaffold demonstrated the greatest potential for BTE, with the highest mechanical strength—20.82-fold greater than the single-network cryogel and 1.75-fold stronger than the PEGDA hydrogel. It also showed the highest normalized ALP content, 3.39-fold and 1.47-fold greater than the IPN and IPN + nHAp scaffolds, respectively, and the highest calcium deposition, 1.30-fold higher than the IPN + nHAp scaffold. In conclusion, this study successfully developed a hybrid scaffold system with improved mechanical characteristics and osteogenesis potential, advancing the field of bone tissue engineering.

Incorporation of small extracellular vesicles in PEG/HA-Bio-Oss hydrogel composite scaffold for bone regeneration

Stem cell derived small extracellular vesicles (sEVs) have emerged as promising nanomaterials for the repair of bone defects. However, low retention of sEVs affects their therapeutic effects. Clinically used natural substitute inorganic bovine bone mineral (Bio-Oss) bone powder lacks high compactibility and efficient osteo-inductivity that limit its clinical application in repairing large bone defects. In this study, a poly ethylene glycol/hyaluronic acid (PEG/HA) hydrogel was used to stabilize Bio-Oss and incorporate rat bone marrow stem cell-derived sEVs (rBMSCs-sEVs) to engineer a PEG/HA-Bio-Oss (PEG/HA-Bio) composite scaffold. Encapsulation and sustained release of sEVs in hydrogel scaffold can enhance the retention of sEVs in targeted area, achieving long-lasting repair effect. Meanwhile, synergistic administration of sEVs and Bio-Oss in cranial defect can improve therapeutic effects. The PEG/HA-Bio composite scaffold showed good mechanical properties and biocompatibility, supporting the growth of rBMSCs. Furthermore, sEVs enhancedin vitrocell proliferation and osteogenic differentiation of rBMSCs. Implantation of sEVs/PEG/HA-Bio in rat cranial defect model promotedin vivobone regeneration, suggesting the great potential of sEVs/PEG/HA-Bio composite scaffold for bone repair and regeneration. Overall, this work provides a strategy of combining hydrogel composite scaffold systems and stem cell-derived sEVs for the application of tissue engineering repair.

Development of multi-layered three-dimensional printed scaffold for sequential delivery of biomolecules

Spatiotemporal control of exogenous growth factors plays a crucial role in the sequential repair of damaged tissues. However, traditional therapeutic trials have mostly relied on the delivery of a single molecule because of the limitations of rapid diffusion and the instability of biomolecules. In this study, we developed a novel strategy using a composite of gelatin and silica as an alternative for the stable and sequential release of biomolecules. Two biomolecules, basic fibroblast growth factor and bone morphogenetic protein-2, were incorporated into two separate composites and sequentially layered onto the activated polymer surface. Each molecule was sequentially released from each layer of the scaffold and the silica composite prevented rapid diffusion owing to its nano-porous structure. The adhesion, proliferation, and osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells were significantly enhanced in the double-layered group containing separately delivered dual molecules compared with the control or single groups. Our developed gelatin–silica composite was successfully placed in double layers on polymer scaffolds, and cellular responses were promoted in this manner. These results demonstrated that our scaffolding system has potential as a therapeutic strategy for the delivery of dual or multiple biomolecules in regenerative medicine.  

A 3-Dimensional Scaffolding System Recapitulates the Hierarchical Osteon Structure.

The bone is composed of solid cortical bone and honeycomb-like trabecular bone. Although the cortical bone provides the substantial mechanical strength of the bone, few studies have focused on its regeneration. As the structural and functional units of the cortical bone, osteons play critical roles in bone turnover. Composed of osteocytes, lamellae, lacunocanalicular network, and Haversian canals, osteons exhibit a delicate and hierarchical architecture. Studies have attempted to reconstruct the osteonal structure with artificial approaches; however, hardly the four elements were recapitulated simultaneously. In this work, a series of bioengineering techniques, including electrospinning, micropatterning, and laser-directed microfabrication, were employed to develop a three-dimensional scaffolding system, which successfully recapitulated the osteon structure in vitro. The physiological morphology and bioactivity of osteocytes were emulated, the intercellular communications between osteocytes were identified, and the concentric lamellae and Haversian canals were simulated as well. This work constructed an in vivo-like platform for osteon study, providing convenience for exploring the interaction among the osteonal elements.

Scaffolds in periodontal regeneration- A brief review

The periodontium constitutes the supportive framework of a tooth, comprising the integration of the periodontal ligament, cementum, gingiva, and alveolar bone. The periodontium's health is compromised by the infiltration of bacteria due to local or systemic factors. Untreated periodontal disease can lead to the loss of attachment and eventual tooth loss, necessitating effective therapy. Tissue engineering is a multidisciplinary approach that combines engineering techniques with life sciences principles to generate biological substitutes for damaged tissues, aiming to restore, maintain, or enhance their function. In recent years, various scaffolding technologies have emerged, transitioning from monophasic to multi-phasic/bioactive scaffold systems, with the goal of three-dimensional regeneration of periodontal tissue rather than mere promotion of healing. This review discusses tissue engineering principles, materials, and recent advancements in scaffold design for periodontal tissue regeneration, along with their efficacy tested both in vitro and in vivo.

Self-adaptive bioactive scaffolds orchestrate diabetic microenvironment remodeling and vascularized bone regeneration

The repair of diabetic bone defects is still challenging as the innate healing process is impaired by adverse microenvironments such as excessive reactive oxygen species (ROS) and insufficient angiogenesis and osteogenesis. Herein, a self-adaptive biocomposite scaffold that can orchestrate sequential regulation of diabetic microenvironment and vascularized bone regeneration was developed for efficient diabetic bone defect repair. The therapeutic scaffold system was meticulously constructed through the incorporation of hydrogel and 3D-printed architecture. In response to the multiple diabetic microenvironment (high level of glucose and ROS), the hydrogel consisting of Vitamin C-loaded phenylboric acid-grafted poly (glutamic acid)/poly (vinyl alcohol) showed adaptive degradation and antioxidative properties by scavenging the intracellular ROS, as well as promoting M2 polarization of macrophages. Furthermore, the copper-doped bioactive glass-contained 3D-printed polycaprolactone within the scaffold system was demonstrated to enhance the mechanical strength and stimulate the in vitro angiogenic and osteogenic performance by releasing copper and silicon ions. Moreover, in a diabetic rat femoral defect model, the biocomposite scaffold showed better angiogenesis and bone regeneration by following diabetic microenvironment remodeling. Therefore, the designed self-adaptive biocomposite scaffold can promote diabetic bone regeneration by sequentially regulating pathological and regenerative cues. This study offers vital insight into the design of a self-adaptive bioactive scaffold for the treatment of diabetic bone defects.

Influence of random geometrical imperfection on loading capacity of scaffold based on stochastic numerical model

The existing data indicate that two-thirds of engineering accidents occur during construction among which engineering accidents caused by scaffold collapse account for a large proportion. Due to the complex mechanical behavior of connection and random nature of scaffold system caused by random geometrical imperfection, the reliability of scaffold system is lower than other kinds of building structures. However, the method considering the random geometrical imperfection is limited. To facilitate the analysis of random geometrical imperfection, the original numerical algorithm is proposed based on ANSYS Parametric Design Language. Through proposed method, two types of geometrical imperfections, i.e., the nodal location error and initial curvature can be automatically considered. The randomness in initial curvature includes random magnitude and random direction. The established numerical model is as close to reality as possible and the process of establishing stochastic numerical model can be automatically finished. The only work that needs to be done is to enter the dimensions of the scaffold. Except the propose of numerical algorithm, the objective of this study is to reveal the influence of geometrical imperfection on random distribution of loading capacity of scaffold system under different load conditions. The influence of random geometrical imperfection on probabilistic distribution of loading capacity is systematically investigated. The results indicated that there may be several buckling modes exist and the buckling mode occurred in actual condition is closely related to the random distribution of geometrical imperfection. The load factor of internal post (point 3) is 8 %–12 % larger than that of corner post. The load factor of side post is 4.7 %–7.2 % larger than that of corner post. The ultimate bending capacity Mu has little influence on the loading capacity of scaffold system when the initial bending stiffness ko is small enough.

Research on Mechanical Properties of New Aluminum Alloy Scaffold Nodes

This article explores the feasibility of using aluminum profiles to design a new type of foldable scaffolding system. To verify the ultimate bearing capacity and failure mode of structural node connectivity points, mechanical performance tests were conducted on the tensile strength of cast aluminum and angle iron nodes to clarify the ultimate bearing capacity and failure mode of the nodes, providing a reference for using aluminum profiles to make new types of scaffolding.

Nanoclay Reinforced Integrated Scaffold for Dual-Lineage Regeneration of Cartilage and Subchondral Bone.

Tissue engineering is theoretically considered a promising approach for repairing osteochondral defects. Nevertheless, the insufficient osseous support and integration of the cartilage layer and the subchondral bone frequently lead to the failure of osteochondral repair. Drawing from this, it was proposed that incorporating glycine-modified attapulgite (GATP) into poly(1,8-octanediol-co-citrate) (POC) scaffolds via the one-step chemical cross-linking is proposed to enhance cartilage and subchondral bone defect repair simultaneously. The effects of the GATP incorporation ratio on the physicochemical properties, chondrocyte and MC3T3-E1 behavior, and osteochondral defect repair of the POC scaffold were also evaluated. In vitro studies indicated that the POC/10% GATP scaffold improved cell proliferation and adhesion, maintained cell phenotype, and upregulated chondrogenesis and osteogenesis gene expression. Animal studies suggested that the POC/10% GATP scaffold has significant repair effects on both cartilage and subchondral bone defects. Therefore, the GATP-incorporated scaffold system with dual-lineage bioactivity showed potential application in osteochondral regeneration.

Electrospun polysuccinimide scaffolds containing different salts as potential wound dressing material.

In this research, we applied electrospinning to create a two-component biodegradable polymeric scaffold containing polysuccinimide (PSI) and antibacterial salts. Antibacterial agents for therapeutical purposes mostly contain silver ions which are associated with high environmental impact and, in some cases, may cause undesired immune reactions. In our work, we prepared nanofibrous systems containing antibacterial and tissue-regenerating salts of zinc acetate or strontium nitrate in different concentrations, whose structures may be suitable for developing biomedical wound dressing systems in the future. Several experiments have been conducted to optimize the physicochemical, mechanical, and biological properties of the scaffolds developed for application as wound dressings. The scaffold systems obtained by PSI synthesis, salt addition, and fiber formation were first investigated by scanning electron microscopy. In almost all cases, different salts caused a decrease in the fiber diameter of PSI polymer-based systems (<500 nm). Fourier-transform infrared spectroscopy was applied to verify the presence of salts in the scaffolds and to determine the interaction between the salt and the polymer. Another analysis, energy-dispersive X-ray spectroscopy, was carried out to determine strontium and zinc atoms in the scaffolds. Our result showed that the salts influence the mechanical properties of the polymer scaffold, both in terms of specific load capacity and relative elongation values. According to the dissolution experiments, the whole amount of strontium nitrate was dissolved from the scaffold in 8 h; however, only 50% of the zinc acetate was dissolved. In addition, antibacterial activity tests were performed with four different bacterial strains relevant to skin surface injuries, leading to the appearance of inhibition zones around the scaffold discs in most cases. We also investigated the potential cytotoxicity of the scaffolds on human tumorous and healthy cells. Except for the ones containing zinc acetate salt, the scaffolds are not cytotoxic to either tumor or healthy cells.

Dye-sensitized sepiolite clay as natural scaffolds for visible light driven photocatalytic hydrogen evolution

Natural clay minerals are increasingly used as superior support materials for various photocatalysts due to their excellent adsorption capacity, negative surface charge, suitable thermal/chemical stability, large specific surface area, and strong surface reactivity, resulting in low agglomeration and suppression of charge recombination. However, they are still insufficient for photocatalysis due to their low efficiency. Therefore, sensitization of clay minerals with dyes to improve the efficiency and specificity of catalysts is considered a promising route for photocatalytic applications. In this work, the effect of dye sensitization on visible light-driven photocatalytic water splitting of microfibrous sepiolite scaffolds as natural photocatalyst supports was investigated for the first time by using various xanthene dyes (eosin Y, rhodamine B and eryhtrosine B (ErB)) and triethanolamine as photosensitizers and sacrificial agents, respectively, in the absence and presence of platinum as a co-catalyst. The clay/dye system was characterized using various techniques such as X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy and energy dispersive X-rays. Sep/ErB photocatalysts produced the highest amount of hydrogen among the other Sep/dye scaffold systems because they act as an effective matrix by preventing nanoparticle aggregation and promoting electron transfer due to their excellent crystal structures and physicochemical properties.

A study of automated intelligent monitoring of scaffolding safety for construction projects

ABSTRACT In recent years, scaffolding has been widely used in construction in advanced industrial countries in Europe, the Americas, and Asia as a temporary facility for new construction and demolition projects. However, in the complex environment of a construction site, temporary facilities such as scaffolding are only managed by the governments of these various countries via the legal system and are inspected through manual observation, resulting in numerous occupational hazards. Today, the lack of attention to temporary structures such as multi-degree-of-freedom discrete structures (e.g. scaffolding) has resulted in a failure to effectively improve the safety, quality, and performance of scaffolded temporary structures. In this study, the scaffolding system of a costly construction site in Taiwan is used as a case study. A BIM model of scaffolding is built based on the unique geographical location of Taiwan and external factors such as earthquakes and typhoons. The study even uses ETABS structural software to identify the structure of scaffolding and analyze the important monitoring points in order to establish a ’scaffolding intelligent monitoring system’ to effectively control the hazards of scaffolding as a medium, thus achieving the goal of construction safety during construction phase.

Assessment of Scaffolding Systems in Addis Ababa Public Building Projects; Current Practice, Related Problems, and Potential Solutions

Assessment of Scaffolding Systems in Addis Ababa Public Building Projects; Current Practice, Related Problems, and Potential Solutions

Enzyme‐Assisted Activation Technique for Producing Versatile Hydrogel Microparticle Scaffolds with High Surface Chemical Reactivity

AbstractAdvancing the integration of nonliving and living components relies heavily on functional hydrogel materials with biocompatibility and customizability. In this study, an enzyme‐assisted surface activation method is developed to produce reactive hydrogel microparticles (HMPs) comprising thiolated hyaluronic acid and hyperbranched poly(β‐hydrazide esters). Fluorescence labeling analysis reveals an over six‐fold increase in surface‐active functional group density on the hydrogels and three‐fold on HMPs after enzyme activation. This enhancement improves accessibility of active elements, facilitating post‐functionalization and optimizing their capacity to support initial cell adhesion and spreading as carriers for cell cultures. Additionally, by utilizing the exposed reactive double bonds on the HMP surfaces post‐enzymatic treatment, thiolated HMPs are produced through a thiol‐ene coupling reaction with thiolated polymers. These thiolated HMPs bond together spontaneously, resulting in the formation of annealed granular hydrogels with interconnected large‐pore networks and a tunable storage modulus (G’) from tens to hundreds of pascals, compatible with most soft tissues. Integrated with 3D bioprinting, this hydrogel ink generates prints that foster cell adhesion, migration, growth, and network formation. Moving forward, integrating various granular hydrogel scaffold systems with the enzyme‐assisted activation technique holds significant promise for enhancing performance and expanding applications in regenerative medicine and innovative living materials.

Recent Advancements in Bone Tissue Engineering: Integrating Smart Scaffold Technologies and Bio-Responsive Systems for Enhanced Regeneration.

In exploring the challenges of bone repair and regeneration, this review evaluates the potential of bone tissue engineering (BTE) as a viable alternative to traditional methods, such as autografts and allografts. Key developments in biomaterials and scaffold fabrication techniques, such as additive manufacturing and cell and bioactive molecule-laden scaffolds, are discussed, along with the integration of bio-responsive scaffolds, which can respond to physical and chemical stimuli. These advancements collectively aim to mimic the natural microenvironment of bone, thereby enhancing osteogenesis and facilitating the formation of new tissue. Through a comprehensive combination of in vitro and in vivo studies, we scrutinize the biocompatibility, osteoinductivity, and osteoconductivity of these engineered scaffolds, as well as their interactions with critical cellular players in bone healing processes. Findings from scaffold fabrication techniques and bio-responsive scaffolds indicate that incorporating nanostructured materials and bioactive compounds is particularly effective in promoting the recruitment and differentiation of osteoprogenitor cells. The therapeutic potential of these advanced biomaterials in clinical settings is widely recognized and the paper advocates continued research into multi-responsive scaffold systems.

Engineering of itaconic acid pathway via co-localization of CadA and AcnA in recombinant Escherichia coli.

Itaconic acid is an excellent polymeric precursor with a wide range of industrial applications. The efficient production of itaconate from various renewable substrates was demonstrated by engineered Escherichia coli. However, limitation in the itaconic acid precursor supply was revealed by finding out the key intermediate of the tricarboxylic acid in the itaconic acid pathway. Efforts of enhancing the cis-aconitate flux and preserving the isocitrate pool to increase itaconic acid productivity are required. In this study, we introduce a synthetic protein scaffold system between CadA and AcnA to physically combine the two enzymes. Through the introduction of a synthetic protein scaffold, 2.1g L-1 of itaconic acid was produced at pH 7 and 37°C. By fermentation, 20.1g L-1 for 48h of itaconic acid was produced with a yield of 0.34gg-1 glycerol. These results suggest that carbon flux was successfully increased itaconic acid productivity.