Tissue Engineering Research Articles

Versatile hydrogels prepared by microfluidics technology for bone tissue engineering applications.

Bone defects are a prevalent issue resulting from various factors, such as trauma, degenerative diseases, congenital disabilities, and the surgical removal of tumors. Current methods for bone regeneration have limitations. In this context, the fusion of tissue engineering and microfluidics has emerged as a promising strategy in the field of bone regeneration. This study describes the classification of microfluidic devices based on the nature of flow and channel type, as well as the materials and techniques required. An overview of microfluidic methods used to prepare hydrogels and the advantages of using these hydrogels in bone tissue engineering (BTE) combining several basic elements of BTE to highlight its advantages is provided. Furthermore, this work emphasizes the benefits of using hydrogels prepared via microfluidics over conventional hydrogels in BTE because of their controlled release of cargo, they can be used for in situ injection, simplify the steps of single-cell encapsulation and have the advantages of high-throughput and precise preparation. Additionally, organ-on-a-chip models fabricated via microfluidics offer a platform for studying cell and tissue behaviors in an authentic and dynamic environment. Moreover, microfluidic devices can be utilized for noninvasive diagnosis and therapy. Finally, this paper summarizes the preclinical and clinical applications of hydrogels prepared via microfluidics for bone regeneration by focusing on their current developmental status, limitations associated with their application, and future challenges, which underscore their potential impacts on advancing regenerative medicine practices.

Evaluation of the comparative efficacy and safety of surgical strategies for long bone defects: a network meta-analysis.

To evaluate the safety and efficacy of various surgical treatments for long bone defects. Despite numerous observational studies, randomized controlled trials (RCTs), and meta-analyses, the optimal surgical treatment for long bone defects remains undetermined. A network meta-analysis (NMA) was conducted. PubMed, Embase, and the Cochrane Library were searched for articles published between 1 January 2000, and 12 January 2023, on surgical treatments for long bone defects. RCTs and observational studies comparing five surgical treatments were selected: the Masquelet technique (MT), bone transport (BT), vascularized bone graft (VBG), non-VBG (NVBG), and bone tissue engineering (BTE). Data were extracted by two independent reviewers. The NMA aggregated direct and indirect evidence. Treatments were ranked using the surface under the cumulative ranking curve (SUCRA) scores. Data are presented as mean differences and 95% confidence intervals. The primary outcomes were the postoperative healing rate, with subgroup analysis based on defect size (4-8cm and >8cm). The secondary outcomes included postoperative complications. This NMA included 23 studies (3 RCTs and 20 observational studies) with 930 participants (median age, 35years). There were no significant differences in clinical outcomes among the treatments. VBG (SUCRA, 75.1%) was rated as optimal for healing, and BTE (SUCRA, 28.5%) was the least effective. BTE had the highest complication rate (SUCRA, 90.9%), whereas NVBG had the lowest complication rate (SUCRA, 27.6%). Subgroup analysis showed reduced heterogeneity: for 4-8cm defects, VBG (SUCRA, 80.4%) was optimal, and for >8cm defects, BT (SUCRA, 76.2%) was optimal. VBG and BT may offer superior clinical outcomes for long bone defects compared to MT, NVBG, and BTE. However, BTE is associated with a high risk of complications. Further high-quality, large-sample RCTs are required to confirm these findings.

Rational design of 3D-printed scaffolds for breast tissue engineering using structural analysis.

Best cosmetic outcomes of breast reconstruction using tissue engineering techniques rely on the scaffold architecture and material, which are currently both to be determined. This study suggests an approach for a rational design of breast-shaped scaffold architecture, in which structural analysis is implemented to predict its stiffness and adjust it to that of the native tissue. This approach can help achieve the goal of optimal scaffold architecture for breast tissue engineering. 
Based on specifications defined in a preliminary implantation study of a non-rationally designed scaffold, and using analytical modeling and finite element analysis (FEA), we rationally designed a polycaprolactone (PCL) made, 3D-printed, highly porous, breast-shaped scaffold with a stiffness similar to the breast adipose tissue. This scaffold had an architecture of a double-shelled dome connected by pillars, with no bottom to allow direct contact of its fat graft with the host's blood vessels (Shelled Hemisphere Adaptive Design (SHAD)). To demonstrate the potential of the SHAD scaffold in breast tissue engineering, a proof-of-concept study was performed, in which SHAD scaffolds were embedded with human adipose derived mesenchymal stem cells (hAdMSCs), isolated from lipoaspirates, and implanted in Nod-Scid-Gamma (NSG) mouse model with a delayed fat graft injection. After 4 weeks of implantation, the SHAD implants were vascularized with a viable fat graft, indicating the suitability of the SHAD scaffold for breast tissue engineering. 
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Systematic development and bioprinting of novel nanostructured multi-material bioinks for bone tissue engineering

A functional bioink with potential in bone tissue engineering must be subjected to critical investigation throughout its intended lifespan. The aim of this study was to develop alginate-gelatin-based (Alg-Gel) multicomponent bioinks systematically and to assess the short- and long-term exposure responses of human bone marrow stromal cells (hBMSCs) printed within these bioinks with and without crosslinking.The first generation of bioinkswas established by incorporating a range of cellulose nanofibrils (CNFs), to evaluate their effect on viscosity, printability and cell viability. Adding CNFs to Alg-Gel solution increased viscosity and printability without compromising cell viability. Inthe second generation of bioinks, the influence of nano-hydroxyapatite (nHA) on the performance of the optimized Alg-Gel-CNF formulation was investigated. The addition of nHA increased the viscosity and improved printability, and an adjustment in alginate concentration improved the stability of the structures in long-term culture. The third generation bioink incorporated RGD-functionalized alginate to support cell attachment and osteogenic differentiation. The optimized bioink composition exhibited improved printability, structural integrity in long-term culture and high hBMSC viability. In addition, the final bioink composition, RGD-Alg-Gel-CNF-nHA, showed osteogenic potential: production of the osteogenic marker proteins (Runx2, OCN), enzyme (ALP), and gene expression (Runx2,OCN). A further aim of the study was to evaluate the osteogenic functionality of cells released from the structures after bioprinting. Cells were printed in two bioinks with different viscosities and incubated at 37 °C in growth medium without additional CaCl2. This caused gelatin to dissolve, releasing the cells to attach to tissue culture plates. The results demonstrated differences in hBMSC osteogenic differentiation. Moreover, the osteogenic differentiation of the released cells was different from that of the embedded cells cultured in 3D. Thus, this systematic investigation into bioink development shows improved results through the generations and sheds light on the biological effects of the bioprinting process.

Multifunctional DNA-Collagen Biomaterials: Developmental Advances and Biomedical Applications.

The complexation of nucleic acids and collagen forms a platform biomaterial greater than the sum of its parts. This union of biomacromolecules merges the extracellular matrix functionality of collagen with the designable bioactivity of nucleic acids, enabling advances in regenerative medicine, tissue engineering, gene delivery, and targeted therapy. This review traces the historical foundations and critical applications of DNA-collagen complexes and highlights their capabilities, demonstrating them as biocompatible, bioactive, and tunable platform materials. These complexes form structures across length scales, including nanoparticles, microfibers, and hydrogels, a process controlled by the relative amount of each component and the type of nucleic acid and collagen. The broad distribution of different types of collagen within the body contributes to the extensive biological relevance of DNA-collagen complexes. Functional nucleic acids can form these complexes, such as siRNA, antisense oligonucleotides, DNA origami nanostructures, and, in particular, single-stranded DNA aptamers, often distinguished by their rapid self-assembly at room temperature and formation without external stimuli and modifications. The simple and seamless integration of nucleic acids within collagenous matrices enhances biomimicry and targeted bioactivity, and provides stability against enzymatic degradation, positioning DNA-collagen complexes as an advanced biomaterial system for many applications including angiogenesis, bone tissue regeneration, wound healing, and more.

Three-Dimensional-Printed Elements Based on Polymer and Composite Materials in Dentistry: A Narrative Review

Abstract 3D printing technologies are manufacturing technologies based on computer-designed digital models that allow fabrication of layered three-dimensional objects. This review aims to present a summary of the literature published on 3D-printed polymer and composite materials in dentistry. A literature search was performed using the PubMed database to identify eligible articles. In total 508 articles were identified based on the original search query, with 362 being eliminated based on the exclusion criteria and 146 articles were screened and based on their abstracts, 68 articles were studied in detail. Subsequently, these articles were divided into three groups based on the area of application: (1) restorative dentistry, which included 3D printed crowns, bridges, and veneers; (2) regenerative dentistry and tissue engineering, such as 3D printed scaffolds; (3) fabrication of oral guides and other appliances, such as surgical guides, dental implants, and surgical splints. In this review the 3D printing technology is described, including its benefits regarding working time, accuracy and overall design and fabrication of products. The review shows that the most studied area of application of printable polymers and composites is regenerative dentistry. Even though these materials are studied for their properties and the effects on the human body as well as the environment, novel materials with specific and revolutionary characteristics that have emerged in recent years are given special attention. However, more research is needed to ensure the safety of use and confirm the characteristics of novel materials in both in vivo and in vitro conditions.

Naturally derived hydrogels for wound healing.

Natural hydrogels have garnered increasing attention due to their natural origins and beneficial roles in wound healing. Hydrogel water-retaining capacity and excellent biocompatibility create an ideal moist environment for wound healing, thereby enhancing cell proliferation and tissue regeneration. For this reason, naturally derived hydrogels formulated from biomaterials such as chitosan, alginate, gelatin, and fibroin are highly promising due to their biodegradability and low immunogenic responses. Recent integrated approaches to utilizing new technologies with bioactive agents have significantly improved the mechanical properties of hydrogels and the controlled release and delivery of active compounds, thereby increasing the efficiency of the treatment processes. Herein, this review highlights the advantages and the challenges of natural hydrogels in wound healing, focusing on their mechanical strength, controlled degradation rates, safety and efficiency validation, and the potential for incorporating advanced technologies such as tissue engineering and gene therapy for utilization in personalized medicine.

Neuroregulation during Bone Formation and Regeneration: Mechanisms and Strategies.

The skeleton is highly innervated by numerous nerve fibers. These nerve fibers, in addition to transmitting information within the bone and mediating bone sensations, play a crucial role in regulating bone tissue formation and regeneration. Traditional bone tissue engineering (BTE) often fails to achieve satisfactory outcomes when dealing with large-scale bone defects, which is frequently related to the lack of effective reconstruction of the neurovascular network. In recent years, increasing research has revealed the critical role of nerves in bone metabolism. Nerve fibers regulate bone cells through neurotransmitters, neuropeptides, and peripheral glial cells. Furthermore, nerves also coordinate with the vascular and immune systems to jointly construct a microenvironment favorable for bone regeneration. As a signaling driver of bone formation, neuroregulation spans the entire process of bone physiological activities from the embryonic formation to postmaturity remodeling and repair. However, there is currently a lack of comprehensive summaries of these regulatory mechanisms. Therefore, this review sketches out the function of nerves during bone formation and regeneration. Then, we elaborate on the mechanisms of neurovascular coupling and neuromodulation of bone immunity. Finally, we discuss several novel strategies for neuro-bone tissue engineering (NBTE) based on neuroregulation of bone, focusing on the coordinated regeneration of nerve and bone tissue.

Gelatin-Based Adhesive Hydrogels with Self-Healing, Injectable and Temperature-Triggered Detachable Properties.

Adhesive hydrogels are emerging as attractive functional materials for various fields, such as tissue engineering, wound healing, E-skins, etc. However, the removal of adhesive hydrogels from covered area may be painful and cause a secondary damage. In the current study, gelatin-based hydrogels are prepared by cross-linking with tannic acid and 4-formylphenyl boronic acid, through simultaneous dynamic covalent boronic ester and imine bond formations. The obtained hydrogels not only present self-healing and injectable properties, but also show tunable adhesiveness that regulated by temperature and oxidation degrees of tannic acid. The maximum adhesion strength of the hydrogels with medium oxidation degree at 37°C can be measured up to 30 kPa on porcine skin, while the value decreased to ≈10 kPa at lowered temperature of 25°C, facilitating the unpainful removal of the hydrogels from skins. This work provides a new approach for the design of functional hydrogels with tailorable adhesiveness.

Advancing Atrial Fibrillation Research: The Role of Animal Models, Emerging Technologies and Translational Challenges

Atrial fibrillation (AF) is the most prevalent sustained cardiac arrhythmia, presenting a significant global healthcare challenge due to its rising incidence, association with increased morbidity and mortality, and economic burden. This arrhythmia is driven by a complex interplay of electrical, structural, and autonomic remodelling, compounded by genetic predisposition, systemic inflammation, and oxidative stress. Despite advances in understanding its pathophysiology, AF management remains suboptimal, with ongoing debates surrounding rhythm control, rate control, and anticoagulation strategies. Animal models have been instrumental in elucidating AF mechanisms, facilitating preclinical research, and advancing therapeutic development. This review critically evaluates the role of animal models in studying AF, emphasizing their utility in exploring electrical, structural, and autonomic remodelling. It highlights the strengths and limitations of various models, from rodents to large animals, in replicating human AF pathophysiology and advancing translational research. Emerging approaches, including optogenetics, advanced imaging, computational modelling, and tissue engineering, are reshaping AF research, bridging the gap between preclinical and clinical applications. We also briefly discuss ethical considerations, the translational challenges of animal studies and future directions, including integrative multi-species approaches, omics technologies and personalized computational models. By addressing these challenges and addressing emerging methodologies, this review underscores the importance of refining experimental models and integrating innovative technologies to improve AF management and outcomes.

Numerical and computational fluid dynamics experimental analysis of novel extended tetra-hybrid Tiwari and Das Sisko nanofluid passed a stenosed artery

The medical industry extensively uses nanoparticles for applications such as wound dressing, artificial organ components, drug delivery, tissue engineering, and cardiovascular disease treatment. The incorporation of nanoparticles into the base fluid enhances the rate of heat transmission and additionally decreases blood pressure. This study aims to examine the effects of a new tetra-hybrid nanofluid model, which includes nanoparticles, on the flow of blood through a stenosed artery with a circular shape. Model partial differential equations (PDEs) incorporate phenomena such as thermal radiation and viscous dissipation. Furthermore, we transform these modeled PDEs into dimensionless ordinary differential equations (ODEs) using self-similarity variables and numerically solve the proposed ODEs using the well-established Lobatto IIIa numerical technique. The impact of several dimensionless parameters on the heat transfer rate, skin friction, velocity, and temperature fields has been computed and analyzed using figures and tables. Moreover, we conducted a computational fluid dynamics (CFD) investigation on a tetra-hybrid nanofluid, using blood as the base fluid. The results indicate that heat transmission is higher in tetra-hybrid nanoparticles compared to tri-hybrid and di-hybrid nanofluids. The volume fraction of nanoparticles in the base fluid increases, resulting in a decrease in the surface drag coefficient and a decrease in the heat transport phenomenon. Amplification in the thermal radiation parameter improves heat transfer, helping to remove toxins and plaque from blood flowing through arteries. An increase in thermal radiation generates excess heat that dilates inflexible arteries, facilitating blood flow. From CFD analysis, it is observed that thermal conduction k and heat transfer coefficient h amplify by improving Reynolds number. Pressure at the outlet interface of the tube decreases from 3058 Pa to 2996 Pa for the case of a 10% volume fraction of nanoparticles. Velocity boundary layer thickness decreases from 1.46 to 1.37 with an increase in the volume fraction of nanoparticles from 1% to 10%. Heat deliverance rate amplifies in the case of tetrahybrid nanofluid 2.5394–2.6147 in contrast to trihybrid nanofluid 2.4008 to 2.4711 by amplifying Rd from 0.7 to 1.1. The surface drag coefficient amplifies by magnifying Re but the Nusselt number diminishes by improving the volume fraction of nanoparticles.

Regional Gene Therapy for Bone Tissue Engineering: A Current Concepts Review

The management of segmental bone defects presents a complex reconstruction challenge for orthopedic surgeons. Current treatment options are limited by efficacy across the spectrum of injury, morbidity, and cost. Regional gene therapy is a promising tissue engineering strategy for bone repair, as it allows for local implantation of nucleic acids or genetically modified cells to direct specific protein expression. In cell-based gene therapy approaches, a variety of different cell types have been described including mesenchymal stem cells (MSCs) derived from multiple sources—bone marrow, adipose, skeletal muscle, and umbilical cord tissue, among others. MSCs, in particular, have been well studied, as they serve as a source of osteoprogenitor cells in addition to providing a vehicle for transgene delivery. Furthermore, MSCs possess immunomodulatory properties, which may support the development of an allogeneic “off-the-shelf” gene therapy product. Identifying an optimal cell type is paramount to the successful clinical translation of cell-based gene therapy approaches. Here, we review current strategies for the management of segmental bone loss in orthopedic surgery, including bone grafting, bone graft substitutes, and operative techniques. We also highlight regional gene therapy as a tissue engineering strategy for bone repair, with a focus on cell types and cell sources suitable for this application.

Xolography for Biomedical Applications: Dual-Color Light-Sheet Printing of Hydrogels With Local Control Over Shape and Stiffness.

Current challenges in tissue engineering include creation of extracellular environments that support and interact with cells using biochemical, mechanical, and structural cues. Spatial control over these cues is currently limited due to a lack of suitable fabrication techniques. This study introduces Xolography, an emerging dual-color light-sheet volumetric printing technology, to achieve control over structural and mechanical features for hydrogel-based photoresins at micro- to macroscale while printing within minutes. A water-soluble photoswitch photoinitiator system and a library of naturally-derived, synthetic, and thermoresponsive hydrogels for Xolography are proposed. Centimeter-scale, 3D constructs with positive features of 20µm and negative features of ≈100µm are fabricated with control over mechanical properties (compressive moduli 0.2kPa-6.5MPa). Notably, switching from binary to grayscaled light projection enables spatial control over stiffness (0.2-16kPa). As a proof of concept, grayscaled Xolography is leveraged with thermoresponsive hydrogels to introduce reversible anisotropic shape changes beyond isometric shrinkage. Xolography of viable cell aggregates is finally demonstrated, laying the foundation for cell-laden printing of dynamic, cell-instructive environments with tunable structural and mechanical cues in a fast one-step process. Overall, these innovations unlock unique possibilities of Xolography across multiple biomedical applications.

In vitro evaluation of bioabsorbable poly(lactic acid) (PLA) and poly-4-hydroxybutyrate (P4HB) warp-knitted spacer fabric scaffolds for osteogenic differentiation

Bioabsorbable textile scaffolds are promising for bone tissue engineering applications. Their tuneable, porous, fibre-based architecture resembles that of native extracellular matrix, and they can sustain tissue growth while being gradually absorbed in the body. In this work, immortalized mouse calvaria preosteoblast MC3T3-E1 cells were culturedin vitroon two warp-knitted bioabsorbable spacer fabric scaffolds made of poly(lactic acid) (PLA) and poly-4-hydroxybutyrate (P4HB), to investigate their osteogenic properties. Scaffold structure and yarn properties were characterized after manufacturing. Cells were seeded on the two scaffolds and treated with osteogenic media for up to 35 days. Both scaffolds supported similar cell growth patterns, featuring a higher cell density on multifilament yarns, which could be beneficial to drive cell proliferation or related phenomena in localized area of the construct. The increase in alkaline phosphatase activity and the calcium deposition observed on some PLA and P4HB scaffolds after 28 and 35 days of culture, confirm their potential to support MC3T3-E1 cells differentiation, however inconsistent mineralization was observed on the scaffolds. Due to their structural and morphological features, ability to support cell attachment and growth, and their limited osteogenic potential, these PLA and P4HB bioabsorbable textile scaffolds are recommended for further investigation for bone tissue engineering applications.

Evaluating the Mechanical and Tribological Properties of 3D Printed PLA/n‐HA/PA66 Composite

ABSTRACTArtificial implants are necessary for orthopedic treatment and the recovery of bone and joint function in disabled individuals. However, existing materials present challenges in manufacturing complex structures and are limited in terms of mechanical and frictional properties. Current research is focused on the development of new environmentally friendly polymer composites for the manufacture of artificial implants, combined with 3D printing technology to improve design flexibility. In this study, nine kinds of PLA/n‐HA/PA66 composite scaffolds with different proportions were prepared using light‐curing 3D printing technology. The physical, mechanical, and tribological properties of the composite scaffolds were compared. The results showed that the PLA/n‐HA/PA66 composite scaffold was superior to traditional polymers, with compressive strength increased by 30–40 MPa and wear resistance increased by 27%–64%. This indicates that it has wide application potential in bone tissue engineering.

Early osteogenic differentiation of human dental stem cells by gelatin/calcium phosphate- Punica granatum nanocomposite scaffold

BackgroundTissue engineering for bone regeneration aims to heal severe bone injuries. This study aimed to prepare and assess the early osteogenic differentiation effects of a gelatin/calcium phosphate- Punica granatum nanocomposite scaffold on stem cells from human exfoliated deciduous (SHED) and human dental pulp stem cells (HDPSCs).MethodsThe electrospinning method was used to prepare a gelatin/calcium phosphate nanocomposite scaffold containing pomegranate (Punica granatum) extract. The physicochemical properties of the scaffold were evaluated. The effect of the scaffold on the selected cells was done by the cell viability evaluation. A special alkaline phosphatase (ALP) kit was utilized to investigate the early osteogenic differentiation effects of the prepared scaffold on HDPSCs and SHED.ResultsThe results showed that the scaffold had uniformly accumulated in the networked form. Besides, the prepared scaffold did not have beads (structural defects). No new interactions were observed in the spectroscopic spectra of the scaffold and these peaks showed the successful formation of the fibrous nanocomposite as well. Furthermore, cell viability percentage was significantly higher for the scaffold compared with the control group (cells without any material) for both HDPSCs and SHED. Early osteogenic differentiation results specified that the ALP activity was significantly higher for the scaffold compared with the control group (cells without any material) for both HDPSCs and SHED.ConclusionThe appropriate physicochemical assay and cellular results (cell viability and early osteogenic differentiation) for the prepared fibrous nanocomposite showed that the use of this nanocomposite can be considered in the construction of various scaffolds in bone and dental tissue engineering.

Cuttlefish-Bone-Derived Hybrid Composite Scaffolds for Bone Tissue Engineering

Current investigations into the fabrication of innovative biomaterials that stimulate cartilage development result from increasing interest due to emerging bone defects. In particular, the investigation of biomaterials for musculoskeletal therapies extensively depends on the development of various hydroxyapatite (HA)/sodium alginate (SA) composites. Cuttlefish bone (CFB)-derived composite scaffolds for hard tissue regeneration have been effectively illustrated in this investigation using a hydrothermal technique. In this, the HA was prepared from the CFB source without altering its biological properties. The as-developed HA nanocomposites were investigated through XRD, FTIR, SEM, and EDX analyses to confirm their structural, functional, and morphological orientation. The higher the interfacial density of the HA/SA nanocomposites, the more the hardness of the scaffold increased with the higher applied load. Furthermore, the HA/SA nanocomposite revealed a remarkable antibacterial activity against the bacterial strains such as E. coli and S. aureus through the inhibition zones measured as 18 mm and 20 mm, respectively. The results demonstrated a minor decrease in cell viability compared with the untreated culture, with an observed percentage of cell viability at 97.2% for the HA/SA nanocomposites. Hence, the proposed HA/SA scaffold would be an excellent alternative for tissue engineering applications.

Strong and tough polyvinyl alcohol hydrogels with high intrinsic thermal conductivity

Although polyvinyl alcohol (PVA) hydrogels display huge potential in tissue engineering, flexible and wearable electronic devices and soft robotics, their low intrinsic thermal conductivity and weak mechanical properties severely limit their wider applications in these areas. Herein, a Hofmeister effect-assisted “directional freezing-stretching” tactic is employed for simultaneously enhancing the intrinsic thermal conduction and mechanical properties of PVA hydrogels. The hydrogels are obtained through directional freezing followed by salting-out treatment and subsequent mechanical stretching and salting-out (DFS). The DFS PVA hydrogel with 15 wt% of PVA and a stretching ratio of 4 (DFS4) exhibits the highest thermal conductivity of 1.25 W/(m·K), which is 2.4 and 2.8 times that of PVA hydrogel prepared through frozen-thawed (FT) [0.52 W/(m·K)] and frozen-salted out (FS) [0.45 W/(m·K)] methods, respectively. The DFS4 PVA hydrogel also possesses greatly improved mechanical performances, exhibiting an elongation at break of 163.1%. In addition, the tensile strength, toughness, and elastic modulus of DFS4 PVA hydrogel significantly increase to 27.1 MPa, 25.3 MJ·m-3, and 21.5 MPa from 0.4 MPa, 0.32 MJ·m-3, and 0.07 MPa for FT PVA hydrogels, respectively. It is elucidated that the salting-out effect generates hydrophobic and crystalline regions, while directional freezing and stretching enhance the chain orientation in the DFS strategy. These effects synergistically contribute to the improvement of thermal conductivity and mechanical properties of PVA hydrogels.

Photocontrolled Bionic Micro-Nano Hydrogel System used Novel Functional Strategy for Cell Delivery and Large-Scale Corneal Repair.

Reproducing the microstructure of the natural cornea remains a significant challenge in achieving the mechanical and biological functionality of artificial corneas. Therefore, the development of cascade structures that mimic the natural extracellular matrix (ECM), achieving both macro-stability and micro-structure, is of critical importance. This study proposes a novel, efficient, and general photo-functionalization strategy for modifying natural biomaterials. Collagen microfibers obtained through electrospinning are functionalized with an active N-Hydroxysuccinimide (NHS) ester, to impart light-curing ability. This approach expands the construction of photo-controllable hydrogel systems beyond conventional single methacrylate (MA) modifications or di-tyrosine bonding, enabling integration with other biomaterials for comprehensive ECM remodeling. Subsequently, the collagen microfibers are then photo-embedded into gelatin methacryloyl (GelMA) via covalent crosslinking to form a fibrous hydrogel, which supports both structural and functional requirements. In terms of biological functionality, the hydrogel promotes significant inward migration and retention of human corneal fibroblasts (hCFs), replicating ECM-like environments. Furthermore, its excellent burst resistance suggests potential as a bioadhesive. In a rabbit model, the hydrogel achieved effective repair of large-sized (6 mm) corneal defects, facilitates epithelial migration, and maintained long-term stability. This work provides valuable guidance for designing efficient and simplified bioactive materials for corneal repair and broader tissue engineering applications.

The role of the interaction of osteoblasts and osteocytes in vivo and during the process of osteodifferentiation in vitro in the key of further prospects of application for the purposes of regenerative medicine

Pathologies associated with impaired bone homeostasis, including osteoporosis, are among the leading diseases in terms of mortality. The development and implementation of tissue engineering approaches based on the use of human mesenchymal stem cells promises to become a highly effective method for their therapy. However, the fundamental cellular mechanism, which is associated with the development of bone diseases, require an additional study. Interactions between osteoblasts and osteocytes of bone tissue undoubtedly plays an important role in maintaining a balance between the processes of bone formation and resorption and involved in the pathogenesis of certain diseases. For more in-depth understanding of the various aspects of these interactions, a representative model is needed. In contrast to cell cultures obtained from the tissues of animal models, the employment of human mesenchymal stem cell cultures reflects more accurately the physiological and phenotypical nuances in human bone. The possibility of creating systems for the co-cultivation of osteoblasts and osteocytes derived from human mesenchymal stem cells and their application in the context of translational medicine is in the focus of this review.