tissue engineering

Ovarian tissue freezing is the most effective method to maintain fertility for immature girls and women diagnosed with cancer. Nonetheless, because of the chance that malignant cells might reappearing following tissue transplantation, it is crucial to isolate the follicles from the frozen-thawed ovarian tissue of these individuals and employ them in the process of in vitro maturation process or artificial ovarian framework. This study aimed to assess the application of neutral red (NR) vital dye alongside collagenase IA for effectively isolating viable follicles from the vitrified human ovarian tissue samples.

Two categories existed: the category with NR and the group without NR. Chopped (0.5×0.5 mm) strips of vitrified-warmed ovarian tissue from 10 transsexual individuals were placed into two falcon tubes with HTCM and Collagenase IA (1mg/ml). Neutral red (NR) was introduced to one of the falcons. Follicles were then isolated mechanically. The morphology, size, and viability of the follicles were assessed. The condition of the follicles was evaluated using fluorescent staining methods involving Calcein-AM and Ethidium homodimer-I. The t-test method was used to evaluate the data.

The number of isolated follicles with Neutral Red (46.50±25/02) exceeded those without NR (6.6±5.58; P < 0/0001). Additionally, according to the morphological studies, a majority of the isolated follicles from the transsexual ovarian cortex were primordial (77.4%), and primary (21.12%) follicles, with only a small number of secondary follicles (1.4%) identified in these tissues. Live/dead staining verified the viability of isolated follicles by displaying a green hue.

The finding indicates that combining collagenase I with the vital dye Neutral red significantly facilitates the of follicles from dense human ovarian tissue.

Tissue engineering is an important treatment strategy for the present and future medicine in the world.

Recently, biomaterial research has led to the development beneficial and useful scaffolds for regenerative medicine.

 In this study, the search for articles using the keywords chitin, chitosan, tissue engineering was carried out through a scientific search independently in Web of Science, Pubmed, Scopus, Science Direct and Google Scholar databases, and finally 94 articles were selected and reviewed.

Chitosan is a generic name for a group of chitin-acetyl compounds. This natural polymer is obtained from renewable sources such as oysters, crustaceans, and seafood waste. Chitosan scaffolds that have a porous structure are easily made by freezing and drying the chitosan solution. The polymer is used in the engineering of bone, cartilage, arteries, skin, and other tissues and can also be used to treat diseases such as cancer and the drug delivery system. In addition, the antioxidant and antimicrobial effects of this compound have led to its broader use in regenerative medicine.

This review article reviews the general properties of chitosan and its various applications in tissue engineering.

Tissue engineering, by designing biological scaffolds and imitating the extracellular environment, helps the growth and proliferation of cells and plays a key role in replacing and repairing damaged tissues. In recent years, the addition of nanoparticles, such as carbon quantum dots, to biological scaffolds has received attention. In this research, the synthesis of polycaprolactone scaffolds containing carbon quantum dots and the investigation of biocompatibility effects and their protection have been discussed.

Carbon quantum dots were synthesized using the pyrolysis method, and polymer scaffolds containing carbon quantum dots were prepared by the electrospinning method. The physical and chemical properties of the scaffold were evaluated by scanning electron microscopy and FTIR spectroscopy. The scaffolds' biocompatibility and antioxidant properties were measured by the MTT method.

Examination of the morphology and chemical showed the appropriate porosity of the scaffold containing carbon quantum dots. The MTT assay significantly enhanced stem cell viability on scaffolds incorporating carbon quantum dots. Furthermore, these scaffolds exhibited a significant protective effect against oxidative stress.

This study showed that the polycaprolactone scaffold containing carbon quantum dots, with high biocompatibility and suitable antioxidant properties, provides an effective substrate for tissue engineering and cell protection under oxidative stress conditions.

Despite significant advances in the prevention, diagnosis, and treatment of cardiac diseases, this condition is still considered one of the major challenges facing the global healthcare system. According to the World Health Organization (WHO) statistics, cardiovascular diseases (CVD) are among the leading causes of mortality worldwide. It is predicted that in the future, due to population aging, urbanization, and lifestyle changes, the mortality rate from cardiac diseases will increase. Current pharmacological approaches only extend the lifespan of patients without providing cardiac tissue repair. In the advanced stages of these diseases, apart from heart transplantation, there is no curative treatment available. However, due to limited suitable donors and post-operative risks and complications such as graft rejection, primary graft failure, and common infections after heart transplant, transplantation is not always feasible. Stem cells have created a wide range of hope in the world since their discovery. With increased research on stem cells and cell therapy in recent decades, researchers have found that utilizing this innovative therapeutic approach can increase lifespan and improve patient outcomes. Various countries have invested millions of dollars in the application of stem cells for treating various diseases in recent years. Embryonic stem cells (ESCs) have great differentiation potential, but their medical application faces severe ethical and religious constraints. The identification of potent induced pluripotent stem cells has revolutionized regenerative medicine. These cells possess all the capabilities of embryonic stem cells and can easily differentiate into cardiac myocytes. Furthermore, the paracrine effects of induced pluripotent stem cells (iPSCs) and extracellular vesicles (EVs) secreted from these cells in regenerative medicine have garnered significant attention. Among extracellular secretory vesicles, researchers have focused more on exosomes. Exosomes are vesicles ranging from 30 to 100 nanometers that have a plasma membrane-like topology and can enter target cells and deliver their cargo. Cardiac patches are a novel achievement resulting from the integration of tissue engineering and cell sciences and are used to improve cardiac injuries. Cardiac patches consist of a natural or synthetic scaffold designed to support and restore myocardial tissue following injury, and they are implanted into the heart tissue. The primary approach to using cardiac patches is to provide physical support to damaged heart tissue. Nowadays, the combination of cardiomyocytes derived from potent induced pluripotent stem cells along with biocompatible materials and growth factors has created specialized cardiac patches capable of precise delivery of many cells and minimizing cellular damages in vivo conditions. This review article aims to explore the latest advances in cardiac regenerative medicine through the use of cardiac patches, induced pluripotent stem cells, and exosomes derived from them; as well as to assess the challenges ahead in cardiac regenerative medicine using the mentioned items to alleviate and improve tissue damage to the heart, and ultimately provide an overview of new perspectives for future research in cardiac regenerative medicine.

Bone tissue engineering is one of the emerging strategies that has been developed to restore the bone of the damaged area without provoking an adverse immune reaction. In this context, the tissue engineering scaffold must be as similar as possible to the natural bone tissue. Bone is a nanocomposite material composed of hydroxyapatite and collagen; hence, the development of nanocomposite scaffolds has been viewed as an appropriate choice for bone tissue restoration. In many situations, these composite materials combine a bioactive mineral phase with a biodegradable polymer phase. The current study aimed to create and analyze a new composite scaffold for bone tissue engineering applications employing bioactive glass nanoparticles (nBG) and fibrin.

The nBG used in this study was based on the 70:30: SiO-2CaO system, which was synthesized using the sol-gel method. Scanning electron microscopy (SEM), X-ray crystallography (XRD), and Fourier transform infrared (FTIR) spectroscopy were used to characterize the fabricated nanoparticles. On the other hand, the whole blood was centrifuged twice at 3000×g to separate the plasma from the blood, and during the next steps, fibrinogen and thrombin were separated from the platelet-free plasma. These components were then mixed with nBG to create an injectable composite scaffold. The composites were subjected to physicochemical characterization, such as degradability and clot formation rate, while human osteoblast-like cells (G292- cell line) were used to assess the scaffold's biocompatibility as well as cell proliferation and differentiation using the MTT and alkaline phosphatase activity tests, respectively.

In the case of bioactive glass nanoparticles, SEM analysis verified the formation of spherical nanoparticles with a diameter of 50 to 110 nm. XRD analysis showed its non-crystalline nature, and the FTIR spectrum demonstrated the presence of Si-O-Si and O-H functional groups. Investigations on the composite of fibrin and bioactive glass nanoparticles (nBG) revealed that incorporating nBG into the fibrin hydrogel enhances its stability and reduces the degradation rate of the scaffold by approximately %40. In vitro investigations on G292- cells revealed that including nBG in the fibrin hydrogel improves cell viability, cell proliferation by approximately %150, and alkaline phosphatase activity by around %45.

Fibrin gel is widely used in bone tissue engineering applications. However, our studies show that when combined with bioactive glass nanoparticles, it is more effective at repairing damaged bones.

A key step in the success of tissue regeneration is the selection of suitable biomaterials for the preparation of extracellular matrix-mimicking scaffolds. Polycaprolactone (PCL) is used as a scaffold in regenerative therapy and drug delivery applications. The purpose of this study is to develop a PCL nano-scaffold enriched with piracetam and octreotide and to investigate its neuroprotective effects on neural progenitor cells.

First, drug-enriched nano scaffolds were prepared and their properties were evaluated with different tests. After preparing the electrospun nano-scaffold enriched with piracetam and octreotide drugs, PC12 cells with a density of 1 x 104 cells were planted in the wells of the 96-well plate. After 2 hours, H2O2 was added to the wells to achieve a final concentration of 57 mM. Cell viability was then determined 24 hours later using the MTT method.

The morphology of the scaffold and its chemical structure showed appropriate porosity. The biocompatibility of the scaffold, which was checked 24 hours after the cultivation of PC12 cells, showed an increase in the viability of the cells as well as the proper connection of the cells on the scaffold.

Our results demonstrated the biocompatibility and non-toxicity of the PCL scaffold, along with increased cell survival on PCL/piracetam and PCL/octreotide scaffolds.

Organoids are small and three-dimensional structures that are similar to natural body organs in terms of components and functions. The technology of using organoids is a new and exciting issue that has created the prospect that individual and complex sets of tissues can be created in the laboratory environment for each patient. This review aims to summarise the current knowledge in the field of designing organoids. For this purpose, we examine the production technology of different tissue organoids and discuss the prospects and disadvantages of using organoids.

The present study is a descriptive review study. In this research, published articles related to this research were searched in PubMed and Scopus databases. Articles in the field of matrix design and cells used in organoid tissue engineering as well as new findings in organoid design were used in this study.

Organoid tissue culture provides scientists a detailed view of how organs form and grow, as well as new insights into human development and disease, Also the opportunity to study how drugs interact with these “small organs" potentially revolutionizes the field of drug development and opens new approaches for personalized medicine. It is hoped that this article will pave the way for the use of this technology in Iran.

Frequent nose defects due to inborn causes or accidents have increased the demand for rhinoplasty. In addition to a functional defect, nose defects are also known as aesthetic defects because the shape of the nose is one of the most prominent features that define the human face. Hence, common reconstruction methods could not meet the requirements caused by limitations. 

This study investigates the ability of different three-dimensional bioprinting methods to repair defects in the nose area.

In this review study, articles available in ScienceDirect, Springer, Wiley, Cambridge, De Gruyter, and Google Scholar databases were used. The search was done using the following keywords: Tissue engineering, nasal cartilage, 3D bioprinting, and bioink materials. The search was done with a time limit of the last 4 years. Out of 300 eligible articles, 159 articles were finally reviewed.

Bioprinting has special potential for repairing nasal cartilaginous tissue. Hydrogels have become an excellent option for mimicking the microenvironment of the host tissue due to their porosity and ability to load different materials, as well as their ability to absorb water and encapsulate cells. On the other hand, the two main cell sources for tissue engineering of nasal cartilage are autologous chondrocytes and mesenchymal stem cells.

Bioprinting technology can bio-mimic the cartilage host tissue to an acceptable degree morphologically, biochemically, and mechanically to be implanted surgically. Although the use of bioprinting at the clinical level still faces limitations, the prospect of this technology is promising since it can fix nasal defects with low cost, unique accuracy, and personalization.

 Identifying protein interactions is one of the main challenges in the fields of biostructure and molecular biology. Despite extensive progress, the exact patterns of protein-protein interactions are still unknown. The main goal of this study is to computationally evaluate the interactions of fibronectin-1 in the extracellular matrix of decellularized trachea and integrins in adipose tissue stem cells in order to provide the most accurate possible visualization of these interactions and their role in biological processes.

 After decellularization of the sheep trachea through the detergent-enzyme method, histological evaluations and ultrastructure photography of the samples were done by scanning electron microscopy. Also, the simulations of fibronectin1 binding of extracellular matrix protein with integrin αvβ1 and α5β3 of stem cells derived from adipose tissue were investigated, and interaction energy analysis was applied to predict the structure of protein-protein complexes using the algorithms available in HDOCK and ClusPro servers.

 The findings indicated the preservation of extracellular matrix components and scaffold ultrastructure. Also, in order to find the most favorable connection states in terms of energy, some of them were reported as stable interactions among the top types of connections. This insight provides a valuable understanding of cell-matrix adhesion, migration, and signaling, with potential implications for therapeutic development.

 The prepared scaffolds are ideal for engineering applications for which computational analysis and experimental data have been used for visualization of stable connection states with energy efficiency between fibronectin and integrin. Also, more studies on cell adhesion modeling in connection with tissue engineering science can provide a suitable field for the development of regenerative medicine in further studies.