mojgan zandi

The fabrication of electrospun nanofibers for drug delivery applications has attracted a great attention in recent years. Polycaprolactone (PCL) is a polymer which has been used frequently in medical and tissue engineering applications. However, the hydrophobic nature of PCL is a drawback which could be resolved by biological materials. The synergistic effect of piperine and ellagic acid on different properties and performance of curcumin containing nanofiber mats has been investigated.

Nanofibers based on PCL with certain amounts of plant extracts were prepared and produced through electrospinning. In order to investigate the effect of each plant extract, single systems containing curcumin or piperine, dual systems containing curcumin/piperine and triple systems containing curcumin/piperine/ellagic acid were produced by electrospinning and various analyses were performed to find out whether they were effective in improving the properties of fiber prepared for medical applications.

The study on microstructure of electrospun mats showed that the diameter distribution of nanofibers was between 50-100 nm and the average fiber diameter in single, double and triple samples changed in the range of 73-87 nm. The antibacterial test revealed that piperine is also an active antibacterial agent like curcumin. In addition, the triple system had a good degree of antibacterial activity (79%). The water uptake and water vapor permeability (WVP) of triple samples were about 337% and 11.56 mg(cm2.h)-1, respectively. The prepared mats showed desirable tensile strength, elasticity and flexibility. Cell viability analysis on electrospun mats indicated that they are not toxic to human dermal fibroblasts (HDF). Therefore, taking into account all the results, it can be concluded that the use of two compounds, ellagic acid and piperine, is effective in increasing the bioavailability of curcumin, and the mats can be used in medical applications as wound dressings..

Poly(ε-caprolactone) (PCL) has considerable mechanical and biological properties that make it a good candidate for tissue engineering applications. PCL alongside proteins and polysaccharides, like gelatin (GEL) and chondroitin sulphate (CS), can be used to fabricate composite scaffolds that provide mechanical and biological requirements for skin tissue engineering scaffolds. The aim of this study was fabricating novel composite nanofibrous scaffold containing various ratios of GEL/CS and PCL using co-electrospinning process.

In this experimental study, PCL mixed with a GEL/CS blend has limitations in miscibility and the lack of a common solvent. Here, we electrospun PCL and GEL/CS coincide separately on the same drum by using different nozzles to create composite nanofibrous scaffolds with different ratios (2:1, 1:1 and 1:2) of GEL to CSPCL, and we mixed them at the micro/nanoscale. Morphology, porosity, phosphate-buffered saline (PBS) absorption, chemical structure, mechanical property and in vitro bioactivity of the prepared composite scaffolds were analysed.

Scanning electron microscopy (SEM) images showed beadless nanofibres at all ratios of GEL to CS-PCL. The composite scaffolds (2:1, 1:1 and 1:2) had increased porosity compared to the PCL nanofibrous scaffolds, in addition to a significant increase in PBS absorption. The mechanical properties of the composite scaffolds were investigated under different conditions. The results demonstrated that all of the composite specimens had better strength when compared with the GEL/CS nanofibres. The increase in PCL ratio led to an increase in tensile strength of the nanofibres. Human dermal fibroblasts (HDF) were cultured on the fabricated composite scaffolds and evaluated by 3-(4,5-dimethylthiazol- 2-yl)-5-(3 carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) analysis and SEM. The results showed the bioactivity of these nanofibres and the potential for these scaffolds to be used for skin tissue engineering applications.

The fabricated co-electrospun composite scaffolds had higher porosity and PBS absorption in comparison with the PCL nanofibrous scaffolds, in addition to significant improvements in mechanical properties under wet and dry conditions compared to the GEL/CS scaffold.

Today, one of the most common hospital and clinical visits of nervous system problems is related to the injuries after accidents that disrupt the lives of injured.According to statistics, half a million surgeries are registered annually in the United States due to the peripheral nerve tissue damage, and the cost of these surgeries is estimated at about 1.5 billiondollars.Also,more than300,000 peripheral nerve injuriesare reported annuallyin Europe and over 5 million worldwide.Trauma is the most common cause of peripheral nervous damage, and neurological injuries often cause muscle-traumatic neuronal damage.In this article, new methods of treatment of peripheral nerve tissue are reviewed.In this paper, new methods and biopolymers used in the treatment of peripheral nerve tissue injuries are reviewed.Generally,peripheral nerve tissue treatment classified into grafts (autograft, allograft, and xenograft) and nerve conduits (decellularized nerve conduits and manufactured nerve conduits). Synthetic neurotransmitters are also divided into three general categories of biodegradation (polyesters, proteins and polysaccharides), synthetic (polyesters, polyurethanes and polyols) and hybrid neurotransmitters, whicheach of these methods is discussed in detail.

Controlled delivery technology of protein/peptide drugs from biodegradable particles has emerged as one of the eminent areas to overcome problems related to macromolecules formulation. The goal of the present study was to develop protein-loaded micro-particles using biodegradable polymer, polycaprolactone (PCL) and hydrogel from beluga cartilage. Bovine serum albumin (BSA) was used as a model for protein/ peptide molecules such as GnRH. The double emulsion (W/O/W) technique was selected as one of the most appropriate methods for preparing a drug delivery system for soluble proteins in water. The first emulsion was prepared using ultrasonic and the mechanical agitator was used for achieving the second emulsion. The hydrogel prepared by enzymatic digestion was used in the first aquatic solution. At the present investigation, three groups were considered as the drug delivery system: G1; (PCL/hydrogel/BSA), G2; (PCL/BSA) and G3; (PCL/Alginate/BSA). Findings showed that the morphology of particles was spherical and non-conglomerated in all groups. The comparison of average particle size among groups was also indicated that the particles.

Tissue engineering is a triad involves three components of different types of cells, growth factor, small biomolecules and scaffold for the purpose of tissue restore, repair and regeneration. In tissue engineering, attachment, growth, proliferation and differentiation of cells require careful control of external factors such as the physical properties of the scaffold as extra cellular matrix (ECM), type and amount of biologically active molecules like small biomolecules, peptides and proteins. Therefore, the interaction of the synthetic and natural scaffolds with the cells must reflect the cellular microenvironment in the body. In this study, we describe a variety of in situ forming injectable hydrogels synthesis with the medical application and tissue regeneration that are crosslinked by chemical bonding or physical interactions. These types of hydrogels have attracted a lot of attention in tissue engineering applications because they can easily transfer the cells or delivered the biomolecules to the damaged tissue. Lack of severe toxicity, minimal injury and pain during surgery could be the other advantages of the injectable hydrogels. A wide variety of chemical methods have been used to crosslink the injectable hydrogels such as click chemistry, Michael addition, Schiff-base, enzymatic reaction and, etc. Some hydrogels can also be cross-linked using physical interactions such as ionic interactions, hydrogen bonding, supramolecular interaction, etc., without external factors in the physiological conditions of the body. In this study, in addition to various methods of synthesis, the practical aspects of hydrogels in regenerative medicine and their achievements in tissue engineering are discussed.

In recent years, nanocomposite scaffolds made of bioactive polymers have found multiple applications in bone tissue engineering. In this study composite nanofibrous structure of gelatin (Gel)/chitosan (Cs)-polycaprolactone (PCL) containing hydroxyapatite (HA) were fabricated using co-electrospinning process. To assay the biocompatibility and bioactivity of electrospun nanocomposite scaffolds, the behavior of human osteosarcoma cells (MG63) on fabricated nanofibers was evaluated using scanning electron microscopy (SEM), fluorescence microscopy analysis, measuring calcium deposits and MTT assay. The SEM micrographs at days 3 and 7 showed high cell attachment and spreading on the nanofibrous scaffolds. The MTT results demonstrated the proliferation of MG-63 cells during 10 days and the positive effect of nanofibers in comparison of cell culture plate. Considering the proliferation rate and calcification extent, the Gel-Cs-HA nanofibers reveal highest biocompatibility for osteoblast cells which could be attributed to the smaller diameter fibers and more mechanical strength in the Gel-Cs-HA scaffold.

In the present study, fish protein hydrolysates (FPH) prepared by hydrolysis of common Kilka (Clupeonella cultriventris­) using the Alcalase enzyme. The antioxidant activity of FPH was evaluated by DPPH and ABTS radical scavenging abilities, reducing power assay, ferrous ion-chelating and total antioxidant activity tests in five different concentrations (1, 2, 3, 4 and 5 mg/mL). The results indicated that with increasing concentration (5 mg/mL), the antioxidant properties of FPH were significantly increased. The highest DPPH radical scavenging activity, ferrous ion-chelating, ferric reducing antioxidant power and total antioxidant activity was related to the concentration of 5 mg/mL. In conclusion, Kilka fish enzymatic hydrolysis leads to the hydrolysate production with antioxidant properties and can be used as food additives after confirming by clinical studies.

Marine organisms represent a valuable source of nutraceuticals and functional compounds. On the other hand, large amount of underutilized by-products are generated from the seafood processing plants annually. Consequently, researchers have identified a number of bioactive compounds including bioactive peptides, collagen and gelatin, oligosaccharides, fatty acids, enzymes, calcium, water-soluble minerals, and biopolymers. Bioactive peptides derived from fish waste can be used as antihypertensive, antioxidative, anticoagulant, and antimicrobial components in functional foods or nutraceuticals and pharmaceuticals due to their therapeutic potential in the treatment or prevention of disease. In this regard, collagen and gelatin are currently used in diverse fields including food, cosmetic, and biomedical industries. Also, chitin, chitosan, and their derivatives possess biologically active polysaccharides and hence they are potential agents for many applications. Hence, seafood by-products are valuable natural resources that show range of functionalities and hence potential materials for biomedical and nutraceutical industries.

Cell transplantation is one of the main strategies for spinal cord injury repair. As OECs of the olfactory mucosa can be obtained by simple biopsy in all individuals without affecting their smell sensation, OECs considered as a promising candidate for autologous transplantation in the nervous system injury, especially for spinal cord repair. Thereby in the current study OECs were cultured from olfactory mucosa of 7 days old rats' pups and their purity was examined by flow-cytometry after simultaneous double staining for p75 and GFAP markers.

7 days old Wistar rats' pups were deeply anesthetized by ketamine / xylazine (60/6mg/Kg). Then the nasal cavity was opened sagittally and the olfactory mucosa was separated from posterior part of nasal septum and at last OECs were obtained from lamina properia of olfactory mucosa and were cultured. The cultured cells were simultaneously immunolabeled for p75 and GFAP markers and finally purity of cultured cells assessed by flow-cytometry.

cultured OECs demonstrated two different morphologies, a spindle shape Schwann-like and an astrocyte-like OECs with flat sheet-like morphology. In addition, simultaneous immunolabeling for p75 and GFAP markers of OECs exhibited   OECs were positive for both markers at the same time. The flow-cytometry results  displayed that 87.9±2.4% of cells were p75/ GFAP double positive cells,1.05±0.4 only p75 positive and 5.8±1.5% were single positive for GFAP.

Purity of cultured OECs in our study is probably more than 87.9% by flow- owing to p75+/S100+ and GFAP+/S100+ olfactory ensheathing cells were not counted. Thus the culture procedure of this study seems to be a good protocol for OECs purifying and cell therapy in CNS damages.

Polymeric membranes are important separation techniques, these membranes are porous or dense and are categorized as symmetric or asymmetric membranes. These devices do separation base on size or structure of the substrates. Nowadayd, different methods are used to fabricate of nanofibrous membranes which attract the researchers’ attention. Nanofibers are prepared via various methods, such that electrospinnig is one of the appropriate, easy and economical methods to fabricate the nanofibers which have found many applications in different scientific fields, including fabrication of nanofibrous membrane for using in filtration process. The characteristics of these membranes are high porosity; of about 80%, highly interconnected pores and large ratio of surface area to volume. On the other hand, polyethersulfone is a polymer with special properties such as heat and chemical resistance as well as biocompatibility. In these membranes select of solvent, process and environmental conditions are many important that affected on nanifibrous substrate properties. Nanofibrous membranes could be improved whit the chemical and physical modification. In this paper, an overview of the process for electrospinning of polyethersulfone membrane has been investigated.

Tissue engineering has the potential to create organ and tissue in the form of de novo. Scaffolds are based on structures existing in the extracellular matrix. The trend of successful use of scaffolds is growing rapidly in organ transplantation and in order to expedite such successful use, structures similar to the target tissue are to be used.The coverage of PCL with Gelatin is devised to enable the surface properties of polymer to have hydrophilicity and permeability.This study is to investigate the cell behavior towards Gelatin-coated poly-caprolactone supramolecular nanofibers polymer. Poly-caprolactone supramolecular nanofibers were prepared by electrospinning method, and were coated with gelatin. Poly-caprolactone supramolecular covered with gelatin has been investigated by FTIR, and scaffolds morphology has been investigated by scanning electron microscope (SEM). L929 fibroblast cells have been cultured on scaffolds, and their cellular activity has been assessed first by MTT test and then has been stained with DAPI to confirm the presence of cells on the nanofibers. The results showed that L929 fibroblast cells, when cultured on nanofibers, such nanofibers can create three-dimensional topography to support the cell growth and cell proliferation, Gelatin-coated poly-caprolactone supramolecular nanofibers has had impact on their biocompatibility. Meantime, MTT assay has confirmed the biocompatibility of the resulting graph. Gelatin- coated poly-caprolactone supramolecular nanofibers, leads to improved surface properties of polymer and to suitable cell behavior.

Fiber orientation is one of the important morphological characteristics of electrospun mats. Electric field between the nozzle and collector which is extremely influenced by electrical conductivity of the collector can be controlled to tailor the orientation of electrospun fibers. We have presented the conductive-insulating collectors as novel means to localize conductive area on the collector surface and subsequently reorganize the electric field. It is demonstrated that the electrospun nanofibers deposit with specific geometries on the hybrid collectors compared to the conventional conductive collectors. In addition، insulting area with different geometries results in different fiber orientations. The square geometry leads to wavy nanofibers with preferentially unidirectional alignment whereas straight nanofibers with completely random orientation are obtained by a collector of circular geometry. These observed morphological changes may be attributed to probable changes in the electrical field. It is also shown that the gap size between the insulating area and the conducting surface influences the fiber orientation in determining bigger gap، lower fiber density and more aligned orientation. Furthermore، the nanofibers deposited on the non-contacting insulating area show no wavy morphology. Our simple strategy can be used for precise tailoring of fiber orientation of the electrospun scaffolds in a desired tissue.

To compare human urothelial and smooth muscle cells attachment and proliferation using three different matrices; poly lactic-co-glycolic acid (PLGA), PLGA/collagen and human amniotic membrane (hAM). Human urothelial and smooth muscle cells were cultured and examined for expression of urothelium (pancytokeratin and uroplakin III) and smooth muscle cells [desmin and alpha smooth muscle actin (α-SMA)] markers. Cells were cultured on three scaffolds; PLGA, PLGA/collagen and hAM. Thereafter, they were analyzed for cell growth on days 1, 3, 7, 14 and 21 after seeding by 3-(4, 5-dimethylthiazole-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Scaffolds were fixed and processed for hematoxylin and eosin (H&E) staining and immunohistochemistry against their cell specific markers after 7 and 14 days of culture. MTT assay results revealed that collagen has improved cell attachment features of PLGA and led to significant increase of MTT signal in PLGA/collagen compared to PLGA (P <. 001) and hAM (P <. 001). hAM was a weaker matrix for both cell types as demonstrated in MTT assay and scanning electron microscope (SEM) images. SEM micrographs showed normal phenotype and distribution on PLGA and PLGA/collagen. In the same line, cells formed a well-developed layer either on PLGA or PLGA/collagen, which maintained expression of their corresponding markers. Our findings demonstrated significant improvement of cell attachment and growth achieved by collagen coating (PLGA/collagen) compared to PLGA and hAM. hAM despite of its natural entity was a weaker matrix for bladder engineering purposes.

The tissue engineering with possible opportunity for repairing، replacing، maintaining، or improving the function of damaged tissue or organ had made a promising approach for treating human life quality. Nano-fibrous electrospun substrates which provide three dimensional substrate can mimic the extra cellular matrix to support the growth of cells. Combination of natural and synthetic polymers improves the strong signaling pathways and also proper cell behavior on the scaffold. In this study nano fibers were prepared with gelatin، PLGA and Gelatin/PLGA via electrospinning; and the cell growth and proliferation of fibroblast L929 on these scaffolds were evaluated. Gelatin was used to improve the biological property of the PLGA nanofibers. After making the Nano-fibers the SEM was used to take some to take some photos، then growth of fibroblast cells was analyzed using the SEM and reverse microscopics. Microscopic images showed that the first 24 hours of cell culture، cells behaved similarly in the three scaffolds but After 72 hours; the Gt/PLGA nanofibers provided a better substrate for adhesion and proliferation. While gelatin Nano-fibers had less growth rate after 72 hours. Also these results were confirmed by SEM. PLGA/Gt nanofiber due to activation of signaling pathways relevant in adhesion protein expression and replication are suitable for tissue engineering. This behavior may be very similar to the natural structure of the extracellular matrix.

The surface modulus and hardness of photo-crosslinkable cyanoacrylate bioadhesives containing TMPTMA and POSS as crosslinking agents were studied using nanoindentation technique. Adhesives containing 2-octyl cyanoacrylate (2-OCA) and different percentages of POSS nanostructures and TMPTMA as crosslinking agents were prepared. 1-Phenyl-1,2-propanedione (PPD) was incorporated as photo-initiator into the adhesive in 4 wt%. Mechanical properties of the surface of the adhesives were measured using nanoindentation technique applying a Berkovich tip. The results (three replicates) were analyzed and compared using one-way ANOVA and Tukey test at a significance level of 0.05. The results showed that by incorporation of crosslinking agents, surface modulus and hardness increased and force loss during holding decreased. The incorporation of crosslinking agents into the adhesives enhanced their elastic properties. The surface modulus and hardness increased by increasing crosslinking concentration. The results also indicated that the elastic work increased, and plastic work dropped due to increasing crosslinking density. The samples which had been stored in water for 24 h before the tests, showed reduced elastic properties due to the plasticization effect of water.

Based on specific applications of electrospinning technology in tissue engineering there is a need for more crucial advances to be made in electrospinning of biocompatible polymer systems. In this study we investigated the effect of surface tension of different solvent systems on the morphology of electrospun nanofibers of gelatin and PLGA. At first the best solvent system was established to optimize nanofiber formation of the polymers. The overall approach of this research was to prepare several solutions of identical concentrations with different solvent systems for electospinning into nanofibes. Finally, the changes in electrospun fiber morphology were studied by scanning electron microscopy (SEM) and the best solvent system was established in order to pave the way for further research on tissue engineering. It is observed that electrospinning of PLGA with lower surface energy solvent system leads to more homogeneous and smooth fibers. This result is similarly obtained for a system of natural gelatin. For ultimate confirmation of these results, it was observed that by changing the solvent system from high surface energy of DMF to lower surface energy of HFIP, the micro-structure of the prepared mat was changed from microspheres to smooth fibers.

A novel gelatin/chitosan scaffold with higher porosity and interconnectivity was designed through salt-leaching/lyophilization (SLL) method. The properties of the fabricated scaffolds were compared with conventional scaffolds، which are obtained by thermally induced phase-separation (TIPS) method. The scaffolds made by phase-separation method have high tensile strength، but suffer from less channel interconnectivity، pore uniformity and also low surface porosity. The microstructure، porosity، phosphate-buffered saline (PBS) solution absorption and tensile strength of the prepared scaffolds by SLL method were studied. In this work، SLL as a two-step technique is introduced for creating porosity to improve both channel interconnectivity and pore uniformity for water-soluble polymers in comparison with the TIPS method. The SLL technique includes two mechanisms: the first، leaching of mixed sodium chloride crystals and particles created during recrystallization of the dissolved NaCl and the second، phase separation during lyophilization at the pore walls. These two steps in porosity formation lead to special pore morphology، which is more suitable for cell culturing because of higher interconnectivity and rich surface porosity in comparison with the phase-separated scaffolds. The prepared scaffolds، using this technique with different salt/polymer ratios and salt crystal size، have 91–97% porosity and 94–190 μm mean pore size with tensile strength of 72–215 kPa and PBS solution absorption between 12. 4 and 19 times dry weight. The pore size of scaffolds prepared using the SLL method could be adjusted independently of polymer solution concentration. These scaffolds have a great potential in skin tissue engineering application.

Nowadays, bone constructs elaborated according to tissue engineering principles are being regarded as an ideal choice for the reconstruction of segmental bone defects. In this study, proliferation and bone differentiation of marrow-derived mesenchymal stem cells (MSCs) were compared in different composite scaffolds containing varying morphologies of nano hydroxyapatite (nHAP). Needle nHAP/PLLA (poly (L-lactide acid)), spherical nHAP/PLLA and rod nHAP/PLLA scaffolds were prepared and 3D cultures of passaged-3 rat MSCs were established using the scaffolds. The loading of the cells onto the scaffold internal spaces was confirmed with microscopy and their proliferation was determined by MTT assay. To compare the osteogenic differentiation of the cells on the scaffold surfaces, osteogenic 3D cultures were established and kept for 21 days. At the end of this period culture mineralization and relative bone-related gene expression were quantified using the alizarin red quantification assay and semi quantitative RT-PCR analysis respectively. ANOVA was used to compare the data. According to the MTT assays, cells adhered to all the studied scaffold surfaces tended to proliferate. In this respect the microenvironment provided by the needle nHAP/PLLA appeared much better than that of either the spherical or rod nHAP/PLLA scaffolds (P<0.05). Similarly, mineralization was observed to be heavier for the needle nHAP/PLLA scaffold compared to the two other composite scaffolds. In addition, the relative expression of coll I, osteocalcin, runx2 and ALP genes all appeared to be significantly higher in the cells cultivated on needle nHAP/PLLA scaffolds versus their spherical and rod counterparts. Overall, needle nHAP/PLLA scaffolds appear to provide the most appropriate matrix for producing bone construct using MSCs.

Bones constructed by tissue engineering are being considered as valuable materials to be used for regeneration of large defects in natural bone. In an attempt to prepare a new bone construct, in this study, proliferation and bone differentiation of marrow-derived mesenchymal stem cells (MSCs) on our recently developed composite scaffolds of nano-, micro-hydroxyapatite/ poly(l-lactic acid) were compared with pure poly(l-lactic acid) scaffolds. For this purpose, some passaged-3 rat MSCs were three-dimensionally cultivated on the scaffold surfaces and their morphology was observed with scanning electron microscopy. Cell proliferations on different scaffolds were examined by MTT assays. Osteogenic cultures were established with the scaffolds loaded with MSCs for 21 days at the end of which culture mineralization; the cell alkaline phosphatase (ALP) Level and the relative expression of selected bone specific genes were quantified and compared to each other. Our results indicated that the cells having been adhered and assumed spherical morphology were able to proliferate in all studied scaffolds. The microenvironment provided by nano-scaffolds appeared much better medium than those of micro-scaffolds and pure PLLA (P < 0.05). The osteogenesis assays indicated to the superiority of nano-scaffolds in supporting MSCs undergoing bone differentiation, which was reflected in high cellular ALP levels, increased bone-related gene expression and enhanced culture mineralization. Collectively, the bone construct prepared with nano-hydroxyapatite/ poly (l-lactic acid) scaffold and proliferated MSCs would be suitable candidate for use in bone regenerative medicine.

This research work focuses on the changes in molecular dynamics of gelatin in the early stages of gelation under temperature variations (273-330 K), pHs (3, 6.5, and 11) and concentrations (1, 3, and 5 %w/w). The early stage of gelation occurs at temperature well above the sol-gel transition point and is accompanied by increasing the viscosity of the solution. The induced variations of the local mobility of the macromolecules are detected by measurements of the spin-spin relaxation time of 1H nuclei of different amino acids. Changes in the rheological characteristics of the gelatin solutions are measured and the effects of acidity, temperature, and concentration on the early stages of the gelatin gelation process are evaluated. The experimental results were analyzed for the mobility of the individual amino acids and of the complete gel network at different temperatures and acidities. Spin-spin relaxation data indicate that the mobility of amino acids in this siane of gelation is not affected by the gelatin concentration, indicating that it is predominantly governed by intra-molecular interactions. As expected, the influence of this interaction on individual amino acids strongly depends on the polarity and their ability to form hydrogen bonds. The variation of the relaxation times reflects the specific role of each individual amino acid during the gelation process. Any deviation from the neutral pH conditions causes a strong increase in the local molecular dynamic, presumably caused by electrostatic repulsion under acidic or basic conditions. At the same time, it leads to decrease in the solution iscosity originally observed under neutral conditions.