Publications by authors named "Amir Mellati"

Regenerative medicine is one of the effective approaches for myocardial infarcted (MI) tissue due to the low capacity of heart for regeneration. However, cell therapy with local administration has shown poor cell retention in the targeted area and limited engraftment capacity at the intended location, resulting in inadequate tissue regeneration. The present study involves mesenchymal stem cell-derived exosomes and encapsulated cells in small and injectable calcium alginate microgels by a specialized microfluidic device to decrease inflammation and increase cell retention in the infarcted tissue.

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Background And Objectives: The main cause of mortality in burn patients is infection from burns. Drug-resistant bacteria are the main causes of wound infection, so alternative antibiotic therapies hold significant importance. The objective of this study was to examine the impact of a collagen hydrogel that contains a nanoemulsion of essential oil on the healing process of infected burn wounds.

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Despite its advantages, electrospinning has limited effectiveness in 3D scaffolding due to the high density of fibers it produces. In this research, a novel electrospinning collector was developed to overcome this constraint. An aqueous suspension containing chitosan/polyvinyl alcohol nanofibers was prepared employing a unique falling film collector.

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In clinical practice, wound care has always been challenging. Hydrogels play a key role in facilitating active wound recovery by absorbing exudates, maintaining moisture, and alleviating pain through cooling. In this study, type I collagen was isolated from the skin of crucian carp (Carassius carassius) and verified by amino acid analysis, FTIR, and SDS-PAGE.

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In situ-forming hydrogels that possess the ability to be injected in a less invasive manner and mimic the biochemical composition and microarchitecture of the native cartilage extracellular matrix are desired for cartilage tissue engineering. Besides, gelation time and stiffness of the hydrogel are two interdependent factors that affect cells' distribution and fate and hence need to be optimized. This study presented a bioinspired in situ-forming hydrogel composite of hyaluronic acid (HA), chondroitin sulfate (CS), and collagen short nanofiber (CSNF).

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Background: Due to loss of peripheral nerve structure and/or function resulting from trauma, accidents, and other causes, peripheral nerve injuries continue to be a major clinical problem. These injuries can cause partial or total loss of sensory, motor, and autonomic capabilities as well as neuropathic pain. PNI affects between 13 and 23 out of every 100,000 people annually in developed countries.

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An ideal antibacterial wound dressing with strong antibacterial behavior versus highly drug-resistant bacteria and great wound-healing capacity is still being developed. There is a clinical requirement to progress the current clinical cares that fail to fully restore the skin structure due to post-wound infections. Here, we aim to introduce a novel two-layer wound dressing using decellularized bovine skin (DBS) tissue and antibacterial nanofibers to design a bioactive scaffold with bio-mimicking the native extracellular matrix of both dermis and epidermis.

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The treatment of full-thickness skin wounds is a problem in the clinical setting, as they do not heal spontaneously. Extensive pain at the donor site and a lack of skin grafts limit autogenic and allogeneic skin graft availability. We evaluated fetal bovine acellular dermal matrix (FADM) in combination with human Wharton's jelly mesenchymal stem cells (hWJ-MSCs) to heal full-thickness skin wounds.

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Regarding their reversible damage of insulin-producing cells (IPCs) and the inefficiency of treatment methods for type 1 diabetes mellitus (T1DM), scientists decided to produce IPCs from an unlimited source of cells. But the production of these cells is constantly faced with problems such as low differentiation efficiency in cell therapy and regenerative medicine. This study provided an ideal differentiation medium enriched with plasma-rich platelet (PRP) delivery to produce IPCs from menstrual blood-derived stem cells (MenSCs).

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Repairing central nervous system (CNS) is difficult due to the inability of neurons to recover after damage. A clinically acceptable treatment to promote CNS functional recovery and regeneration is currently unavailable. According to recent studies, injectable hydrogels as biodegradable scaffolds for CNS tissue engineering and regeneration have exceptionally desirable attributes.

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Background: Healing the full-thickness skin wounds has remained a challenge. One of the most frequently used grafts for skin regeneration is xenogeneic acellular dermal matrices (ADMs), including bovine ADMs. This study investigated the effect of the source animal age, enzymatic versus non-enzymatic decellularization protocols, and gamma irradiation versus ethylene oxide (EO) sterilization on the scaffold.

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In December 2019, a betacoronavirus was isolated from pneumonia cases in China and rapidly turned into a pandemic of COVID-19. The virus is an enveloped positive-sense ssRNA and causes a severe respiratory syndrome along with a cytokine storm, which is the main cause of most complications. Therefore, treatments that can effectively control the inflammatory reactions are necessary.

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Background: Using a different source of stem cells to compensate for the lost beta cells is a promising way to cure diabetic patients. Besides, the best efficiency of insulin-producing cells (IPCs) will appear when we culture them in an environment similar to inside the body. Hence, three-dimensional (3D) culture ameliorates the differentiation of diverse kinds of stem cells into IPCs compared to those differentiated in two-dimensional (2D) culture.

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Among the many polymers introduced for bone tissue engineering, natural polymers have more advantages due to their high biocompatibility and biodegradability, despite their low mechanical properties. Herein, gelatin nanofibers with and without magnesium oxide (MgO) and graphene oxide (GO) nanoparticles were fabricated by electrospinning. The fabricated gelatin and gelatin/GO/MgO nanofibers were examined using scanning electron microscopy, protein adsorption, cell attachment and viability assays.

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Hydrogels have attracted much attention for biomedical and pharmaceutical applications due to the similarity of their biomimetic structure to the extracellular matrix of natural living tissues, tunable soft porous microarchitecture, superb biomechanical properties, proper biocompatibility, etc. Injectable hydrogels are an exciting type of hydrogels that can be easily injected into the target sites using needles or catheters in a minimally invasive manner. The more comfortable use, less pain, faster recovery period, lower costs, and fewer side effects make injectable hydrogels more attractive to both patients and clinicians in comparison to non-injectable hydrogels.

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Human endometrial stem cells (hEnSCs) that can be differentiated into various neural cell types have been regarded as a suitable cell population for neural tissue engineering and regenerative medicine. Considering different interactions between hormones, growth factors, and other factors in the neural system, several differentiation protocols have been proposed to direct hEnSCs towards specific neural cells. The 17β-estradiol plays important roles in the processes of development, maturation, and function of nervous system.

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An efficient drug delivery system was introduced. The carrier was synthesized by combination of an ordered mesoporous carbon (CMK3) and a thermosensitive polymer, poly(N-isopropylacrylamide), known as PNIPAAm. The polymers with 2 different chain lengths (PNIPAAm-100n and PNIPAAm-400n) were synthesized and each of the polymers was embedded in CMK3 to form composite materials.

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Mimicking the zonal organization of native articular cartilage, which is essential for proper tissue functions, has remained a challenge. In this study, a thermoresponsive copolymer of chitosan-g-poly(N-isopropylacrylamide) (CS-g-PNIPAAm) was synthesized as a carrier of mesenchymal stem cells (MSCs) to provide a support for their proliferation and differentiation. Microengineered three-dimensional (3D) cell-laden CS-g-PNIPAAm hydrogels with different microstripe widths were fabricated to control cellular alignment and elongation in order to mimic the superficial zone of natural cartilage.

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Providing a controllable and definable three-dimensional (3D) microenvironment for chondrogenic differentiation of mesenchymal stem cells (MSCs) remains a great challenge for cartilage tissue engineering. In this work, poly(N-isopropylacrylamide) (PNIPAAm) polymers with the degrees of polymerization of 100 and 400 (NI100 and NI400) were prepared and the polymer solutions were introduced into the preprepared chitosan porous scaffolds (CS) to form hybrids (CSNI100 and CSNI400, respectively). SEM images indicated that the PNIPAAm gel partially occupied chitosan pores while the interconnected porous structure of chitosan was preserved.

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Poly (N-isopropylacrylamide) (PNIPAAm) is a thermosensitive polymer with various biomedical applications. We examined molecular weight (MW)-dependent cytotoxicity of PNIPAAm. Our results indicated that low-MW PNIPAAm (degree of polymerization (DP)=35) is inherently toxic to cells.

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