Papers by Keyword: Tissue Engineering

Abstract: Bone regeneration is a complex physiological process that helps in healing of fractured bone and maintaining skeletal integrity. Chitosan and Hydroxyapatite (HAp) are bio-materials that enhance bone regeneration. The synergistic influence draws the attention of researchers to the use of Chitosan-HAp composite for bone regeneration. However, there is a need to explore more on material properties, fabrication techniques, biological mechanisms and challenges in bone regeneration applications. The biocompatibility, osteoconductivity, and synergistic effects of chitosan and HAp play a vivid role in bone regeneration. This paper explores recent advancements in the development of scaffolds that mimic the extracellular matrix and promote effective bone healing, fabrication techniques such as freeze-drying, 3D printing and nanotechnology, it also explores limitations regarding mechanical properties, scalability, and regulatory hurdles despite the promising attributes of chitosan-HAp composites. The findings show that the use of machine-learning (ML) in forecasting design output and preclinical applications can improve the composite development for effective bone regeneration. Therefore, future research directions should focus on alternative biopolymers, and employ ML techniques to enhance scaffold design and functionality to optimise material properties.

Abstract: Tissue engineering provides a promising approach to addressing the global shortage of organ and tissue donors by developing biological substitutes that can restore or enhance tissue function. This study presents the development and characterization of PEG-PVA biodegradable hydrogels, synthesized through chemical crosslinking with varying concentrations of glutaraldehyde, for tissue engineering applications. Mechanical, thermal, and structural properties were systematically analyzed to determine the optimal formulation for different applications. Hydrogels synthesized with 0.10g and 0.15g of glutaraldehyde were selected for detailed evaluation. The hydrogel with 0.10g glutaraldehyde exhibited a tensile strength of 1200 MPa, a glass transition temperature (Tg) of ～50°C, and a swelling ratio of 7.65, demonstrating superior mechanical robustness and thermal stability for load-bearing applications such as bone and cartilage regeneration. In contrast, the hydrogel with 0.15g glutaraldehyde, with a tensile strength of 1000 MPa, a Tg of 45°C, and a swelling ratio of 4.49, showed greater flexibility and a denser microstructure, making it more suitable for soft tissue applications requiring controlled degradation. These results underscore the importance of tailoring crosslinking density to optimize hydrogel performance for specific biomedical applications. Future studies should explore the behavior of these hydrogels in biologically relevant environments, including enzymatic degradation and in vivo testing. With further development, PEG-PVA hydrogels could play a key role in regenerative medicine, offering customizable mechanical and degradation properties for diverse clinical applications.

Abstract: This study explores the development and optimization of 3D bioprinted polylactic acid (PLA) and pectin composite scaffolds for tissue regeneration. The viscoelastic properties of the PLA/pectin blends were assessed to determine their impact on printability and mechanical performance. A range of PLA-to-pectin ratios was investigated to evaluate their rheological behavior, extrusion capabilities, and shape fidelity. Mechanical properties, such as compressive strength, were analyzed to ensure the scaffolds could support cellular activities and tissue ingrowth. Additionally, cell viability post-printing was assessed using human fibroblast cells to evaluate the biocompatibility of the scaffolds. The results indicated that the 90/10 PLA to pectin ratio offered an optimal balance between printability, mechanical integrity, and biological performance, making it a promising candidate for tissue engineering applications.

Abstract: Due to the fact that mechanical properties in macroscale cannot respond to that of cell wall features, it has become important to investigate nanomechanical characteristics of scaffold materials and make suitable modifications if needed. Conventional methods of mechanical testing cannot characterize the spatial distribution of material, with non-uniform stiffness, at nanoscale. One of the important methods of nanoscale testing is the force mapping using the atomic force microscope. In the present study, A comprehensive approach was developed to determine and characterize surface distribution of elastic modulus for soft biomaterials at nanoscale. Elastic modulus has been determined for collagen fibers, modified with different percentage of bio-glass nonoparticles, 0%, 30% and 60%, by applying tiny forces (1 nN). The experiments are carried out in phosphate buffer saline (PBS) pH ~ 7, to mimic the physiological environment. The scanning was performed at two different spots for each sample and three different scan sizes to investigate the large scale and short scale heterogeneity, respectively. Deep-lying structures have been sensed by varying applied load (2 nN). Our results are in agreement with previous reports. The results show increasing elasticity with increase of bioglass in collagen samples. Yet adding more bioglass decreases the stiffness of collagen fibers to the point where they become difficult to handle. Samples appear to be strongly heterogeneous with increasing the scan size. The depth sensing measurements manifest higher elasticity which reflects the lower degree of freedom in the deep-lying structures.

Abstract: The main purpose of this study is to synthesize nano-hydroxyapatite/cellulose (nHAP/Cel) and nano-hydroxyapatite/chitosan (nHAP/CS) scaffolds via co-precipitation method for bone tissue engineering due to their suitable biocompatibility, cytotoxicity and mechanical properties. The characterizations of these scaffolds were investigated by Infrared absorption spectra (FT-IR), X-ray Diffraction (XRD), and Scanning Electron Microscope (SEM). The cytotoxicity of these nanoparticles was evaluated with bone marrow cell using the 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazoliumbromide) (MTT) assay. The porosity of scaffolds was estimated 87%. The results indicate that the nano composite scaffolds have good morphology, tissue biocompatibility and biodegradability to be used for tissue engineering.

Abstract: In this study, a synthetic scaffold was prepared from polycaprolactone (PCL) and polyurethane (PU) blend, in a ratio of [2:1] [PCL: PU], using electrospinning technique. Electrospun scaffolds from native PCL and PU were also prepared for comparison, using the same polymer concentration 15% weight/ volume w/v. The detailed microstructure and other properties, like mechanical properties, porosity, and contact angle were investigated and compared between the three prepared scaffolds. Then, the survival, adhesion, proliferation and penetration of rat embryonic fibroblast (REF) cells were evaluated on these three prepared scaffolds after being in vitro cultured with these cells for 21 days, using scanning electron microscope (SEM) analysis and histological analysis. The results showed that, all the studied properties, including mechanical properties and contact angle were enhanced by combining PU with PCL in the [PCL: PU] scaffold. The average diameter of fiber and the average size of pore were suitable and proper for cell attachment, cell proliferation, and also the big average pore size in [PCL: PU] scaffold was enough for cell penetration to form a three- dimension 3-D structure, which is the aim of this study.

Abstract: The current study involves synthesis of a composite films of sodium alginate (Alg), polyvinylalcohol and NanoGraphene oxide (GO) for tissue engineering applications. Solvent casting was used to make the polymeric composite films (Alg-Pva-Go), which may exhibit a synergic activity of the components for tissue repair. The influence of various GO concentrations on the films properties was also investigated. The scaffold has outstanding physicochemical and biological properties. The composite film's high swelling degree and contact angle reveals its high hydrophilicity, making it appropriate for tissue engineering. The antimicrobial activity on Staphylococcus aureus were studied. Furthermore, the antimicrobial test showed that the films composite was resistant to S. aureus. Seeding (AD-MSC) cells into the composite films exhibited an increase in cell adhesion and proliferation when compared to the Alginate and Polyvinylalcohol film in vitro experiments, indicating that the GO has a good influence on the films characteristics, which can utilization in tissue engineering applications.

Abstract: New strategies have been developed to design advanced functional biomimetic structures. This paper reviewed the benefits and drawbacks of biomaterials that are used to manufacture 3D scaffolds in tissue engineering. In this paper, latest technological methods, scaffold requirements in development of single form, composite form and cell-laden based scaffolds, classification on the basis of geometry and main material is explained elaborately. These scaffolds promote different molecules can be delivered to tissue and stimulate cell growth. These cells have a therapeutic effect. The paper discusses the various 3D bio printed structures and the difficulties they encounter. The impacts of biologically functionalized biomaterials on soft and hard tissue engineering in vitro and in vivo are discussed. The paper summarized the future prospects for bioactive scaffolds, that can be used in clinical therapy.

Abstract: The meniscus is a part of the knee joint consisting of a medial and lateral component between the femoral condyles and the tibial plateau. Meniscal tears usually happen in younger and active people due to sports or daily activities. Some approaches are chosen for meniscus replacement and regeneration from the problems above, such as meniscal repair, meniscal allograft transplantation, gene therapy techniques, and tissue engineering techniques. Biomaterials and tissue engineering have a primary role in meniscus regeneration and replacement. The cell-material interactions are influenced by the biomaterials' design, structure, and composition to promote the growth o meniscus tissue. This study aims to give a brief review of the cell-material interaction in the replacement and regeneration process of the meniscus. Based on several studies, the use of growth factors in the meniscal regeneration and replacement could modulate and promote angiogenesis, differentiation, and cell migration beneficial in the repair process of the meniscus. Furthermore, combining the Mesenchymal Stem Cells and growth factors in healing the meniscal tears could be one of the best approaches to obtaining the new tissue resembling the meniscal tissue. The follow-up and long-term studies in meniscus regeneration and replacement are needed and recommended, especially implanting with good chondroprotective and long-term evaluation to obtain the best properties similar to the natural meniscus.

Abstract: New tissue-engineered vascular prostheses of small diameter (4mm) based on biodegradable polymer backbone – poly (ε-caprolactone) (PCL) and its composition with poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV/ PCL) were created. The full cycle of surface modification of the backbone with polyvinylpyrrolidone and drugs permitted to increase significantly the atrombogenic and antimicrobial properties of prostheses and provide its effective matrix properties. Both types of the developed constructs are suitable for testing in vivo. The energy characteristics of the prosthesis surfaces at the different interfaces were determined. It was established that the value of the energy of the "polymer, saturated with octane/water" interface can be used as a parameter for predicting cell adhesion and proliferation in the case when it is difficult to determine or to distinguish the energy characteristics of the surfaces of tissue-engineered materials at the interface with air.