Application of electrospun nanofibers in bone, cartilage and osteochondral tissue engineering

Development of bilayer tissue-engineered scaffolds: combination of 3D printing and electrospinning methodologies

Although different fabrication methods and biomaterials are used in scaffold development, hydrogels and electrospun materials that provide the closest environment to the extracellular matrix have recently attracted considerable interest in tissue engineering applications. However, some of the limitations encountered in the application of these methods alone in scaffold fabrication have increased the tendency to use these methods together. In this study, a bilayer scaffold was developed using 3D-printed gelatin methacryloyl (GelMA) hydrogel containing ciprofloxacin (CIP) and electrospun polycaprolactone (PCL)-collagen (COL) patches. The bilayer scaffolds were characterized in terms of chemical, morphological, mechanical, swelling, and degradation properties; drug release, antibacterial properties, and cytocompatibility of the scaffolds were also studied. In conclusion, bilayer GelMA-CIP/PCL-COL scaffolds, which exhibit sufficient porosity, mechanical strength, and antibacterial properties and also support cell growth, are promising potential substitutes in tissue engineering applications.

Improving rodents and humans cardiac cell maturityin vitrothrough polycaprolactone and polyurethane nanofibers

Currently, numerous studies are conducted using nanofibers as a scaffold for culture cardiac cells; however, there still needs to be more research evaluating the impact of the physicochemical properties of polymer nanofibers on the structure and function of cardiac cells. We have studied how poly(ϵ-caprolactone) and polyurethane nanofibrous mats with different physicochemical properties influence the viability, morphology, orientation, and maturation of cardiac cells. For this purpose, the cells taken from different species were used. They were rat ventricular cardiomyoblasts (H9c2), mouse atrial cardiomyocytes (CMs) (HL-1), and human ventricular CMs. Based on the results, it can be concluded that cardiac cells cultured on nanofibers exhibit greater maturity in terms of orientation, morphology, and gene expression levels compared to cells cultured on polystyrene plates. Additionally, the physicochemical properties of nanofibers affecting the functionality of cardiac cells from different species and different parts of the heart were evaluated. These studies can support research on understanding and explaining mechanisms leading to cellular maturity present in the heart and the selection of nanofibers that will effectively help the maturation of CMs.

Co- and Triaxial Electrospinning for Stem Cell-based Bone Regeneration

Bone tissue is composed of organic minerals and cells. It has the capacity to heal for certain minor damages, but when the bone defects surpass the critical threshold, they need fixing. Bone regeneration through natural and synthetic biodegradable materials requires various steps, such as manufacturing methods and materials selection. A successful biodegradable bone graft should have a high surface area/ volume ratio, strength, and a biocompatible, porous structure capable of promoting cell adhesion, proliferation, and differentiation. Considering these requirements, the electrospinning technique is promising for creating functional nano-sized scaffolds. The multi-axial methods, such as coaxial and triaxial electrospinning, are the most popular techniques to produce double or tri-layered scaffolds, respectively. Recently, stem cell culture on scaffolds and the application of osteogenic differentiation protocols on these scaffolds have opened new possibilities in the field of biomaterials research. This review discusses an overview of the progress in coaxial and triaxial technology through biodegradable composite bone materials. The review also carefully elaborates the osteogenic differentiation using stem cells and their performance with nano-sized scaffolds.

Effect of different HA/β-TCP coated 3D printed bioceramic scaffolds on repairing large bone defects in rabbits

BACKGROUND

Treatment of large segmental bone defects is still a major clinical challenge, and bone grafting is the main method. The development of novel bone graft substitutes will help solve this problem.

METHODS

Porous bioceramics hydroxyapatite (HA) scaffolds coated with different ratios of HA/β-tricalcium phosphate (β-TCP) were prepared by 3D printing. The scaffolds were sampled and tested in large segmental bone defect rabbit models. X-ray, micro-computed tomography (CT), hematoxylin and eosin (HE) staining, Van-Gieson staining, and type I collagen staining were performed to find the best scaffolds for large segmental bone defect treatment.

RESULTS

The average length, diameter, compressive strength, and porosity of the bioceramics scaffolds were 15.05 ± 0.10 mm, 4.98 ± 0.06 mm, 11.11 ± 0.77 MPa, and 54.26 ± 5.38%, respectively. Postoperative lateral radiographs suggested the scaffold group got better bone healing and stability than the blank group. Micro-CT showed new bones grew into the scaffold from the two ends of the fracture along the scaffold and finally achieved bony union. The new bone volume around the scaffolds suggested the 3:7 HA/β-TCP-coated bioceramic scaffolds were more favorable for the healing of large segmental bone defects. The results of HE, Van-Gieson, and type I collagen staining also suggested more new bone formation in 3:7 HA/β-TCP-coated bioceramic scaffolds.

CONCLUSION

3:7 HA/β-TCP-coated porous bioceramics scaffolds are more conducive to the repair of large bone defects in rabbits. The results of this study can provide some reference and theoretical support in this area.

Nanofibers: A current era in drug delivery system

Nanofibers have a large area of surface variable 3D topography, porosity, and adaptable surface functions. Several researchers are researching nanofiber technology as a potential solution to the current problems in several fields. It manages cardiovascular disorders, infectious diseases, gastrointestinal tract-associated diseases, neurodegenerative diseases, pain treatment, contraception, and wound healing. The nanofibers are fabricated using various fabrication techniques, such as electrospinning, phase separation, physical Fabrication, and chemical fabrication. Depending on their intended use, nanofibers are manufactured using a variety of polymers. It comprises natural polymers, semi-synthetic polymers, synthetic polymers, metals, metal oxides, ceramics, carbon, nonporous materials, mesoporous materials, hollow structures, core-shell structures, biocomponents, and multi-component materials. Nanofiber composites are a good alternative for targeted gene delivery, protein and peptide delivery, and growth factor delivery. Thus, nanofibers have huge potential in drug delivery, which enables them to be used for various applications and can revolutionize these therapeutic areas. This review systematically studied nanofibers' history, advantages, disadvantages, types, and polymers used in nanofiber technology. Further, polymers and their types used in the preparation of nanofibers were summarised. Mainly review article focuses on the fabrication method, i.e., electrospinning and its types. Finally, the article discussed the applications and recent advancements of nanofabrication technology.

Recent development in multizonal scaffolds for osteochondral regeneration

Osteochondral (OC) repair is an extremely challenging topic due to the complex biphasic structure and poor intrinsic regenerative capability of natural osteochondral tissue. In contrast to the current surgical approaches which yield only short-term relief of symptoms, tissue engineering strategy has been shown more promising outcomes in treating OC defects since its emergence in the 1990s. In particular, the use of multizonal scaffolds (MZSs) that mimic the gradient transitions, from cartilage surface to the subchondral bone with either continuous or discontinuous compositions, structures, and properties of natural OC tissue, has been gaining momentum in recent years. Scrutinizing the latest developments in the field, this review offers a comprehensive summary of recent advances, current hurdles, and future perspectives of OC repair, particularly the use of MZSs including bilayered, trilayered, multilayered, and gradient scaffolds, by bringing together onerous demands of architecture designs, material selections, manufacturing techniques as well as the choices of growth factors and cells, each of which possesses its unique challenges and opportunities.

Recent advances in modified poly (lactic acid) as tissue engineering materials

As an emerging science, tissue engineering and regenerative medicine focus on developing materials to replace, restore or improve organs or tissues and enhancing the cellular capacity to proliferate, migrate and differentiate into different cell types and specific tissues. Renewable resources have been used to develop new materials, resulting in attempts to produce various environmentally friendly biomaterials. Poly (lactic acid) (PLA) is a biopolymer known to be biodegradable and it is produced from the fermentation of carbohydrates. PLA can be combined with other polymers to produce new biomaterials with suitable physicochemical properties for tissue engineering applications. Here, the advances in modified PLA as tissue engineering materials are discussed in light of its drawbacks, such as biological inertness, low cell adhesion, and low degradation rate, and the efforts conducted to address these challenges toward the design of new enhanced alternative biomaterials.

Cellular therapy and tissue engineering for cartilage repair

Articular cartilage (AC) has limited capacity for repair. The first attempt to repair cartilage using tissue engineering was reported in 1977. Since then, cell-based interventions have entered clinical practice in orthopaedics, and several tissue engineering approaches to repair cartilage are in the translational pipeline towards clinical application. Classically, these involve a scaffold, substrate or matrix to provide structure, and cells such as chondrocytes or mesenchymal stromal cells to generate the tissue. We discuss the advantages and drawbacks of the use of various cell types, natural and synthetic scaffolds, multiphasic or gradient-based scaffolds, and self-organizing or self-assembling scaffold-free systems, for the engineering of cartilage constructs. Several challenges persist including achieving zonal tissue organization and integration with the surrounding tissue upon implantation. Approaches to improve cartilage thickness, organization and mechanical properties include mechanical stimulation, culture under hypoxic conditions, and stimulation with growth factors or other macromolecules. In addition, advanced technologies such as bioreactors, biosensors and 3D bioprinting are actively being explored. Understanding the underlying mechanisms of action of cell therapy and tissue engineering approaches will help improve and refine therapy development. Finally, we discuss recent studies of the intrinsic cellular and molecular mechanisms of cartilage repair that have identified novel signals and targets and are inspiring the development of molecular therapies to enhance the recruitment and cartilage reparative activity of joint-resident stem and progenitor cells. A one-fits-all solution is unrealistic, and identifying patients who will respond to a specific targeted treatment will be critical.

New Forms of Electrospun Nanofibers Applied in Cardiovascular Field

Cardiovascular disease (CVD) is one of the leading causes of death worldwide. In recent years, regenerative medicine, tissue engineering and the development of new materials have become the focus of attention this field, and electrospinning technology to prepare nanofibrous materials for the treatment of cardiovascular diseases has attracted people's attention. Unlike previous reviews, this research enumerates the experimental methods and applications of electrospinning technology combined with nanofibrous materials in the directions of myocardial infarction repair, artificial heart valves, artificial blood vessels and cardiovascular patches from the perspective of cardiovascular surgery. In the end, this review also summarizes the limitations, unresolved technical challenges, and possible future directions of this technology for cardiovascular disease applications.