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This study seeks to simulate both the chemistry and piezoelectricity of bone by synthesizing electroconductive silane-modified gelatin-poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) scaffolds using the freeze drying technique.

Recently biomaterials utilized for designing scaffolds in tissue engineering are not cost-effective and eco-friendly. As a result, we design and develop biocompatible and bioactive hydrogels for osteo-tissue regeneration based on the natural polysaccharide chitosan. Three distinct hydrogel components were used for this.Hydrogels networks were created using chitosan 2% (CTS 2%), carboxymethyl chitosan 2% (CMC 2%), and 50:50 mixtures of CTS and CMC (CTS/CMC 50:50). Furthermore, scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), degradation, and swelling behavior of design hydrogels were studied. Also, the cytocompatibility and osteo-differentiation potency were examined by encapsulating mesenchymal stem cells derived from adipose tissue (AMSCs) on the designed hydrogels.According to the findings, our results showed an acceptable pore structure, functional groups, and degradation rate of the designed hydrogels for in vitro evaluation. In addition, employing CMC instead of CTS or adding 50% CMC to the hydrogel component could improve the hydrogel's osteo-bioactivity without the use of external osteogenic differentiation agents.The CMC-containing hydrogel not only caused early osteogenesis but also accelerated differentiation to the maturity phase of osteoblasts.

This paper discussed a patient with dens invaginatus (DI) in all maxillary incisors that was accompanied by supernumerary tooth and also bifid cingulum, lingual pit, and talon cusp on the other teeth. DI is a rare developmental malformation usually seen in the maxillary lateral incisors of permanent dentition. A healthy 22-year-old Iranian woman was referred for the treatment of carious teeth. Following comprehensive clinical and radiographic examination, that was diagnosed DI affecting all maxillary central and lateral incisors. Left maxillary central incisor was Type I and the other incisors were Type II, according to Oehlers classification. Furthermore, she had supernumerary tooth and Class III malocclusion. All teeth responded to sensibility tests, except right maxillary central incisor that was diagnosed pulp necrosis and asymptomatic apical periodontitis. Conventional root canal therapy was done for the right maxillary central incisor using mineral trioxide aggregate and gutta percha and AH26 sealer by thermoplastic method. After 18 months of follow-up, clinical and radiographical examination revealed periapical healing of the right maxillary central incisor and absence of pulp and periapical pathosis in other incisors. The early recognition of DI, correct diagnosis, and appropriate management of this tooth is essential to ensure favorable treatment outcome.

Electrospinning is a promising approach for the development of fibrous tissue engineering (TE) scaffolds suitable for hard and soft tissues. Apart from physicomechanical properties, electrospun fibers are required to incorporate bioactive cues to control cellular functions, including facilitating biomineralization and osteogenic differentiation in case of bone TE, as well as vascularization, to support successful tissue regeneration. In recent years, bioactive glass (BG) addition to electrospun biopolymer fibers has shown promising results in enhancing the properties of fibers, including the improvement of biological performance. In this article, a comprehensive overview of BG‐containing electrospun polymer composite fibers is presented, identifying the parameters that affect the mechanical properties as well as the biological response in vivo and in vitro. Subsequently, the effects of BG addition on the properties of the scaffolds are discussed. Recent developments in the fields of bone regeneration, wound healing, and drug delivery using BG‐containing electrospun fibrous scaffolds are described in detail. Essential aspects related to BG‐polymer composite fibers for translational research in TE are highlighted for future research in this field.

Protein coating is a strategy for modifying and improving the surface functional properties of nanomaterials. However, the underlying mechanism behind protein coating formation, which is essential for its practical applications, remains largely unknown. Herein, we investigate the fundamental molecular mechanism of protein coating formation. Polydopamine nanospheres (PDANS) coated with bovine serum albumin (BSA) are examined in this study due to their wide biomedical potential. Our results demonstrate that BSAs can flexibly bind to PDANS and maintain their structural dynamicity. Our findings unveil that regular structure formation arises from BSAs lateral interactions via electrostatic forces. Notably, the protein coating modified PDANS surface enhances cell adhesion and proliferation as well as osteogenic differentiation. Such an enhancement is attributed to complementary surface properties provided by the dynamic PDANS-BSA complex and regular structure caused by BSA-BSA interactions in protein coating formation. This study provides a fundamental understanding of the molecular mechanism of protein coating formation, which facilitates the further development of functional protein-coated nanomaterials and guides the bioengineering decision making for biomedical applications, especially in bone tissue engineering.

Cartilage injuries are common problems that increase with the population aging. Cartilage is an avascular tissue with a relatively low level of cellular mitotic activity, which makes it impossible to heal spontaneously. To compensate for this problem, three-dimensional bio-printing has attracted a great deal of attention in cartilage tissue engineering. This emerging technology aims to create three-dimensional functional scaffolds by accurately depositing layer-by-layer bio-inks composed of biomaterial and cells. As a novel bio-ink, a decellularized extracellular matrix can serve as an appropriate substrate that contains all the necessary biological cues for cellular interactions. Here, this review is intended to provide an overview of decellularized extracellular matrix-based bio-inks and their properties, sources, and preparation process. Following this, decellularized extracellular matrix-based bio-inks for cartilage tissue engineering are discussed, emphasizing cell behavior and in-vivo applications. Afterward, the current challenges and future outlook will be discussed to determine the conclusing remarks.

In this study, retinoic acid loaded-PLGA-gelatin matrixes were prepared with both freeze-casting and freeze-drying techniques. Herein, the effect of unidirectional microstructure with tunable pores on release profile, cellular adhesion, migration, and differentiation was compared. Morphological observation determined that highly interconnected porous structure can be formed, but lamellar pore channels were observed in freeze-casting prepared constructs. The absorption ratio was increased, and the biodegradation rate was decreased as a function of the orientation of microstructure. The in-vitro release study illustrated non-Fickian release mechanism in both methods, so that erosion has predominated over diffusion. Accordingly, PLGA-gelatin scaffolds prepared with freeze-drying technique showed no adequate erosion due to the rigid structure, while freeze-casting one presented more favorable erosion. Microscopic observations of adhered P19 embryonic cells on the scaffolds showed that the freeze-casting matrixes with unidirectional pores provide a more compatible microenvironment for cell attachments and spreading. Besides, it facilitated cell migration and penetration inside the structure and may act as guidance for neuron growth. Improvement in the expression of neural genes in unidirectionally oriented pores proved the decisive role of contact guidance for nerve healing. It seems that the freeze-cast PLGA-gelatin-retinoic acid scaffolds have initial features for nerve tissue regeneration studies.

In this study, dexamethasone-loaded gelatin–starch scaffolds were fabricated by the freeze-drying technique under different cooling temperatures and polymeric compositions. The constructs were modified via [3-(2,3-epoxypropoxy)-propyl]-trimethoxysilane coupling agent in order to produce a bioactive network structure for bone tissue engineering applications. Herein, the synergistic effect of [3-(2,3-epoxypropoxy)-propyl]-trimethoxysilane and dexamethasone was examined on the bioactivity and osteogenic behavior of scaffolds. Based on scanning electron microscopy micrographs, more fine pores were formed at higher freezing temperatures. The prepared microstructure at a rapid freezing rate resulted in diminished mechanical properties and a greater level of swelling and durability compared with a slow freezing rate. According to the acquired results, the mechanical strength decreased, while both absorption capacity and mass loss rate increased as a function of starch addition. Furthermore, the enhancement of hydrophilicity and reduction of mechanical stability enhanced the dexamethasone release levels. In addition, the synthesized constructs confirmed the positive effect of [3-(2,3-epoxypropoxy)-propyl]-trimethoxysilane and dexamethasone on biomimetic mineralization of the scaffolds. Supporting the cellular adhesion and proliferation alongside the expression of alkaline phosphatase, especially in the presence of dexamethasone, was the other advantage of synthetic scaffolds as a bone reconstructive substitute. Accordingly, drug-loaded hybrid constructs seem to be promising for further preclinical and clinical investigations in bone tissue engineering.

In this study, polyurethane (PU) scaffolds were fabricated by electrospinning technology and modified through the deposition of polydopamine (PDA) on the activated surface under oxygen plasma treatment. Herein, the effect of the modification process on the homogeneous surface coating and the changes in the physicochemical and biological properties were evaluated. Morphological observations demonstrated decoration of the nanofibrous microstructure with PDA, while the uniformity and homogeneity of the deposited layer increased after plasma oxygen treatment. Hydrophilicity measurements and swelling ratio indicated a remarkable improvement in the interaction of scaffolds with water molecules when the PDA coating is applied on the surface of the treated nanofibers. The biomineralization of the samples was characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) images. It was found that PDA has the capability for mineralization, and the amount of deposited hydroxyapatite increased as a function of PDA content. Thein vitroevaluation of constructs indicated great improvement in cell-scaffold interactions, biocompatibility, and alkaline phosphatase activity after coating the PDA on the plasma-modified matrix. These results suggest that PDA coating, especially after oxygen plasma treatment, improves the physicochemical andin vitroproperties of PU scaffolds for bone tissue engineering application.

Background and Aim: Common causes of dental discoloration include trauma, drugs, genetic defects, decay, and age. In order to correct discoloration of pulpless teeth, internal bleaching is recommended. The aim of this study was to compare microleakage of resin modified glass ionomer and OrthoMTA used as an intraorifice barrier in non-vital bleaching. Materials and Methods: In this experimental study, 36 extracted mandibular premolars were selected and randomly divided into two experimental (n = 16) and two control groups (n = 2). 2mm of OrthoMTA and RMGI cements were placed as intraorifice barriers in the experimental groups. Subsequently, we placed a mixture of sodium perborate and 30% hydrogen peroxide as internal bleaching material into the canal and replaced it every three days. Leakage was measured using pH diffusion method by a digital PH meter. Data were statistically analyzed by using T- independent test and repeated measures and variance analysis (P

Introduction Dental trauma mainly affects the anterior teeth, which can have significant effects on tooth function, aesthetics, and speech. Extrusion refers to the relative tooth displacement out of the socket. The emergency treatment in this injury is repositioning the tooth and flexible splint for 2 weeks. Case Report: The patient is 8-year-old boy with a chief complaint of trauma to the teeth. After confirming the diagnosis of traumatic extrusion injury, the tooth # 9 was repositioned and splinted. During one-year follow-up, root canal calcification and normal response to pulp sensibility tests were observed.

The successful design of a hydrogel for tissue engineering requires a profound understanding of its constituents’ structural and molecular properties, as well as the proper selection of components. If the engineered processes are in line with the procedures that natural materials undergo to achieve the best network structure necessary for the formation of the hydrogel with desired properties, the failure rate of tissue engineering projects will be significantly reduced. In this review, we examine the behavior of proteins as an essential and effective component of hydrogels, and describe the factors that can enhance the protein-based hydrogels’ structure. Furthermore, we outline the fabrication route of protein-based hydrogels from protein microstructure and the selection of appropriate materials according to recent research to growth factors, crucial members of the protein family, and their delivery approaches. Finally, the unmet needs and current challenges in developing the ideal biomaterials for protein-based hydrogels are discussed, and emerging strategies in this area are highlighted.

The development of peptide-based materials has emerged as one of the most challenging aspects of biomaterials in recent years. It has been widely acknowledged that peptide-based materials can be used in a broad range of biomedical applications, particularly in tissue engineering. Among them, hydrogels have been attracting considerable interest in tissue engineering because they mimic tissue formation conditions by providing a three-dimensional environment and a high water content. It has been found that peptide-based hydrogels have received more attention due to mimicking proteins, particularly extracellular matrix proteins, as well as the wide variety of applications they are capable of serving. It is without a doubt that peptide-based hydrogels have become the leading biomaterials of today owing to their tunable mechanical stability, high water content, and high biocompatibility. Here, we discuss in detail various types of peptide-based materials, emphasizing peptide-based hydrogels, and then we examine in detail how hydrogels are formed, paying particular attention to the peptide structures that are incorporated into the final structure. Following that, we discuss the self-assembly and formation of hydrogels under various conditions, as well as the parameters to be considered as critical factors, which include pH, amino acid composi- tion within the sequence, and cross-linking techniques. Further, recent studies on the development of peptide-based hydrogels and their applications in tissue engineering are reviewed.

To investigate the potential of biomaterials for bone repair, Ginkgo biloba (GB)-loaded polylactic- co-glycolic acid microspheres were synthesized via solvent evaporation technique, and scanning electron microscopic (SEM) micrographs indicated a spherical and smooth surface in which the particles were distributed in the range of 1–7 µm. Chitosan–hydroxyapatite (HA) matrixes incorporated with polymeric spheres were fabricated using the freeze-drying method. SEM micrographs demonstrated an interconnected porous structure in which porosity and pore size reduced as a function of HA and microsphere addition. Fourier transform infrared spectrum illustrated the ability of sodium tripolyphosphate in cross-linking of composite scaffolds. Swelling ratio presented that higher amount of microspheres and the addition of HA reduce the ability of interaction with water molecules. The GB release behavior of hybrid scaffolds confirmed that the addition of HA significantly reduces release ratio because of a slight reduction in pore size and PBS absorption capacity, but higher amount of microspheres resulted in an increase in release level. According to the results, the synthesized hybrid scaffolds have the initial physicochemical features for further studies in terms of in vitro and in vivo assays.

In this study, mussel-inspired polydopamine nanospheres (∼400 nm) were synthesized via spontaneous oxidative polymerization of dopamine hydrochloride. The creation of bioactive template provided an opportunity for the biomimetic formation of hydroxyapatite layers through soaking of polymeric samples in 10 × -simulated body fluid (10 × -SBF) solution and heating microwave radiation. According to the results, microwave irradiation supported the rapid and homogeneous formation of HA on the surface of bioinspired spheres, and synthesized HA showed nearest Ca/P ratio to biological HA. In addition, Fourier transform infrared spectrum, X-ray diffraction, and atomic force microscopy tests confirmed the effectiveness of microwave rays on biomimetic mineralization. Biocompatibility of the constructs and improving cellular spreading on the HA-coated species indicated their potential for biomedical applications.

In this study, electrospinning was selected to fabricate randomly oriented polyurethane (PU) nanofibers for tissue engineering application, and the surface of scaffolds was exposed to oxygen plasma flow. The morphology structure of the PU scaffolds before and after oxygen plasma treatment was observed using scanning electron microscopy (SEM) micrographs, and the fiber diameter distribution was measured using Image J software. The results demonstrated that oxygen plasma modification reduces the fiber diameter without any other special effects on fiber microstructure. Water drop contact angle and swelling ratio of PU constructs were performed to estimate the water-scaffolds interactions. The results revealed improvement of hydrophilicity by oxygen plasma treatment. Atomic force microscopy test was done to analyze a topological characteristic of the scaffolds, and it was found out that oxygen plasma treatment decreases the roughness of the scaffolds. The biological behavior of the scaffolds was investigated by SEM observation and MTT assay after L-929 fibroblast cells culture. In vitro assays demonstrated biocompatibility, cellular attachments, and filopodia formation on plasma modified samples. These results suggest that oxygen plasma treatment improves the physicochemical and biological properties of PU scaffolds to create a more hydrophilic surface which facilitates cell attachments and proliferation.

Thin-film composite (TFC) membranes with high water flux and low reverse salt flux are the most conventional materials for forward osmosis (FO) process. However, these membranes are not suitable for natural or wastewaters treatment due to the intrinsic physicochemical and surface properties of the rejection layer. The present work shows the fabrication of new thin film nanocomposite (TFN) forward osmosis membranes incorporate superhydrophilic modified silica nanoparticles. Surface of silica nanoparticles were functionalized by quaternary ammonium groups and subsequently were coated using superhydrophilic wheel polyoxometalates (POM). TFN membranes containing different weight ratio of nanoparticles in PA rejection layer were synthesized by interfacial polymerization (IP) of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) as monomers in aqueous and organic solution, respectively. POM coated silica nanoparticles were dispersed in aqueous solution of MPD monomer prior to IP process. The changing in the performance and physicochemical properties of TFN membranes incorporating with superhydrophilic nanoparticles were investigated by different instrumental analysis and were compared with a pristine TFC membrane. Compared to pristine TFC membrane, the TFN membrane with 0.2 wt% nanoparticle incorporation (TFNw0.2) showed superior water flux (18 vs. 31 LMH in FO mode) and negligible increases in reverse salt flux (6.25 vs. 8.45 gMH). In addition, better anti-fouling propensity toward protein (bovine serum albumin, BSA) and organic (sodium alginate, SA) foulant was observed. Therefore, Using newly developed thin film nanocomposite membranes may provide a novel class of high-performance membrane for FO processes.

In this study, polycaprolactone (PCL) scaffolds were fabricated via the freeze-casting method. Moreover, the surface of prepared constructs was modified using an oxygen plasma treatment technique for grafting the gelatin in order to improve physicochemical and biological properties. Field emission scanning electron microscopy (FE-SEM) micrographs demonstrated interconnect and unidirectional pore channels. At the same time, the modification procedure showed slight effects on the lamellar microstructure of pores. Fourier transforms infrared (FTIR) spectroscopy determined chemical characterization, which evaluates the effect of the surface treatment on the chemical structure of scaffolds. The wettability of the constructs was investigated by a water drop contact angle and swelling ratio tests. The results illustrated an increment in hydrophilicity after oxygen plasma modification, while the immobilization of gelatin enhanced more the potential of interaction with water molecules. Moreover, the increase in the biodegradation ratio was observed after modification. The in-vitro performance of constructs before and after gelatin immobilization was investigated bt the cell culture assay. Accordingly, modified scaffolds with gelatin support cell attachment and filopodia formation compared with the PCL ones. Besides, the biocompatibility of polymeric matrixes was proved by MTT assay. The results suggest that gelatin grafting on oxygen plasma modified PCL scaffold can be useful in wound healing.

Electrospinning is a versatile technology for the fabrication of nanofibrous matrixes to regenerate defects. This study aims to develop a functionalized and electroconductive polymeric matrix to improve rat bone marrow mesenchymal stem cell adhesion, proliferation, and differentiation. Herein, the influence of the chemical composition of the substrate on homogeneous modification of the surface with mussel-inspired polydopamine (PDA) is focused. Accordingly, the deposition of PDA on the surface was proved by Fourier transform infrared spectroscopy. Morphologies of the scaffolds demonstrated homogeneous decoration of the polyvinyl alcohol (PVA)/polyurethane (PU)-polyaniline (PANI) matrixes with PDA, while a lower density of mussel-inspired polymer was observed in bare PU-PANI constructs. Although uniform and dense precipitation of PDA reduced conductivity of scaffolds 1.2 times compared with the samples with a low density of the PDA, 1.1 and 1.2 times enhancement in tensile strength and Young's modulus, respectively, were the strength of the applied process, especially in bone tissue engineering area. Contact angle measurements demonstrated about two times reduction in measured values, which shows improvement in hydrophilicity of PDA-modified PVA/PU-PANI fibers compared with PDA-coated PU-PANI ones. Swelling ratio and mass loss ratio calculations revealed enhancement in measured values as a function of homogeneous and dense coating, which arise from hydrophilicity of the polymeric substrate. The bioactivity test indicated that a dense layer of PDA strongly supports formations of hydroxyapatite-like crystals. Moreover, homogeneous decoration of conductive matrixes with PDA showed suitable cell viability, adhesion, and spreading while cell-scaffolds interactions improved under electrical stimulation. Higher expression of alkaline phosphatase and secretion of Collagen I under the electrical field proved the applicability of modified electroconductive scaffolds for further preclinical and clinical studies to introduce as a reconstructive bone substitute.

Objectives Intracellular reactive oxygen species (ROS) induced by receptor activator of NF‐kB ligand (RANKL) has been proven to be a critical factor in the development of osteoclasts. This study aimed to prove that schisandrin A (Sch), a novel anti‐oxidant compound, is able to suppress osteoclastogenesis and prevent bone loss in ovariectomized (OVX) mice by suppressing ROS via nuclear factor erythroid 2‐related factor (Nrf2). Material and Methods Micro‐CT was used to detect bone formation. The effects of Sch on receptor activator of nuclear factor‐κB (NF‐κB) ligand (RANKL)‐induced reactive oxygen species (ROS) were measured by dihydroethidium (DHE) staining in vivo and 2',7'‐dichlorodihydrofluorescein diacetate (DCFH‐DA) staining in vitro. Immunofluorescence staining was used to detect the expression of Nrf2 in vivo. siRNA was used to evaluate the effect of Nrf2 in osteoclastogenesis. Results Sch suppresses RANKL‐induced ROS production by regulating nuclear factor erythroid 2‐related factor (Nrf2) in vitro and vivo. Mechanistically, Sch enhances the expression of Nrf2 by regulating the degradation of Nrf2. Further, Sch suppresses phosphorylation of P65 and its nuclear translocation, as well as the degradation of IκBα. Collectively, our findings reveal that Sch protects against OVX‐induced bone loss by suppressing ROS via Nrf2. Conclusions Our results showed the potential of anti‐oxidant compound schisandrin A in the treatment of osteoporosis, highlighting Nrf2 as a novel promising target in osteoclast‐related disease., Proposed scheme of Sch restrains osteoclastogenesis by inhibiting reactive oxygen species and activating Nrf2 signalling. Sch suppresses RANKL‐induced ROS production by regulating nuclear factor erythroid 2‐related factor (Nrf2) in vitro and vivo. Mechanistically, Sch enhances the expression of Nrf2 by regulating the degradation of Nrf2. Further, Sch suppresses phosphorylation of P65 and its nuclear translocation, as well as the degradation of IκBα. Collectively, our findings reveal that Sch protects against OVX‐induced bone loss by suppressing ROS via Nrf2.

Biocompatibility and biodegradability characteristics of some polymers make them an excellent candidate to fabricate porous scaffolds for tissue engineering applications. However, the scaffold mechanical properties and biodegradation rate are vital for bone tissue replacement applications, which can be improved using proper fabrication techniques and cross-linker. In this investigation, Chitosan-polyvinyl alcohol scaffolds were prepared by freeze-drying technique utilizing various weight ratios of 3-Glycidoxypropyl trimethoxysilane (GPTMS) as a bioactive inorganic crosslinker. SEM micrographs indicated interconnected porous structures of cross-linked scaffolds while the average diameter of pores increased as a function of cross-linker enhancement. FTIR analysis was performed to confirm interactions among organic and inorganic components. The mechanical strength test represented that increasing GPTMS content improves the compressive strength of samples. The absorption capacity of the scaffolds in the PBS solution exhibited a decrease in water uptake and biodegradation by increasing silane coupling agent concentration. The formation of needle-like apatite particles proved suitable bioactivity of cross-linked samples. Moreover, MTT assay and ALP expression showed an acceptable adhesion, spreading, proliferation, and differentiation of MG-63 cells on the silane-contained scaffolds. Obtained results warrant further preclinical and clinical evaluations.

Photothermal therapy is one of the promising approaches toward cancer treatment. To date, several compounds have been developed for this application, among which nanoparticles are attracting ever-increasing attention. One of the obstacles in developing efficient photothermal nanoparticle agents is their off-target effect which is mainly mediated via non-specific interactions with proteins. Such interaction not only reduces the bioavailability of the agent but also will cause protein aggregation that can be lethal. So, gaining knowledge on the mechanisms mediating such interactions will facilitate development of more effective agents. Our last studies showed the mechanism of action of two modified gold nanoparticles, folic acid functionalized gold nanoparticles (FA-AuNPs) and gold shelled Fe

Forward osmosis (FO) as a membrane-based water treatment process, utilizes the natural osmotic pressure gradient as driving force, originates from two solutions with different concentrations separated by a semipermeable membrane. Eligible FO draw agents of low cost, high water flux, easy recovery, and low reverse draw solute flux play a key role in the FO process. Some recently developed polymer hydrogels showed attractive features as draw agents in the FO process. In this study, a biocompatible and biodegradable polymer hydrogel was synthesized via free radical polymerization of the carboxymethylcellulose and acrylic acid as biocompatible monomers and subsequently used as an FO draw agent. In addition, to enhance the FO performance of polymer hydrogel, quaternary graphene oxide (QGO) as nanomodifier was synthesized and incorporated within the hydrogel matrix. The successful incorporation of QGO and its effect on FO performance of the hydrogel was systematically investigated. The obtained results showed that the QGO modified hydrogels have higher swelling ratio than the pure polymer hydrogel due to their more polar functional groups and more porous structures. The QGO hydrogel also has significantly higher water flux than the pure polymer hydrogel.

So far, many studies have focused on biodegradable scaffolds for tissue engineering purposes. Herein, a starch-based biodegradable scaffold was fabricated by the freeze-drying method and cross-linked using a different concentration of 3-glycidoxypropyl-trimethoxysilane (GPTMS). Field emission scanning electron microscopy (FE-SEM) micrographs indicated an interconnected porous microstructure in which the porosity decreased as a function of starch and GPTMS content. Increasing the mechanical stability and decreasing absorption capacity and biodegradation ratio affected by the higher concentration of cross-linker and the changes in structure as a function of cross-linker enhancement. Moreover, the mineralization of hybrid structures in simulated body fluid was proved by FE-SEM image and X-ray diffraction analysis. Results indicated the more GPTMS in scaffolds led to more hydroxyapatite formation. The ability of the growth and proliferation of bone marrow mesenchyme stem cells on the constructs confirmed the ability of scaffolds for bone tissue engineering applications.

In this study, we functionalized multiwall carbon nanotube with polar groups including COOH and OH groups (F.MWCNT) and synthesized composite polymer hydrogel via dispersion in monomer solution and by using a simple poly (acrylic acid-co-maleic anhydride) (PAA-co-PMA) crosslinking reaction. Incorporation of the F.MWCNT phase into the PAA-co-PMA hydrogel network was verified using Fourier transformation infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis. The physico-chemical properties of the composite polymer hydrogels were investigated and compered to pure hydrogel. In addition, the effect of F.MWCNT incorporation on polymer hydrogels performance as forward osmosis draw agent was studied. The results indicated that the addition of F.MWCNT (1.2 wt%) within the polymer hydrogel enhanced the water adsorbing capacity of the composite hydrogel as expected. Furthermore, the composite hydrogel (1.2 wt% of incorporated F.MWCNT) displayed a much higher water flux compared with the pure PAA-co-PMA polymer hydrogel during the FO test. The facile and efficient preparation of the F.MWCNT incorporated PAA-co-PMA composite hydrogel means it will have potential applications as a novel draw agent.

Polyurethane (PU) has been extensively used in vascular tissue engineering due to its outstanding mechanical performance and blood compatibility behavior. Here, biomimetic PU-based scaffolds were prepared using an electrospinning technique and gelatin-heparin was introduced as a surface modifier after oxygen plasma treatment to improve cell attachment and release an anticoagulation agent. Morphology, Fourier transform infrared (FTIR) spectroscopy, compression strength, swelling and biodegradation ratio, drug release level and cellular interactions were evaluated. According to the scanning electron microscopy (SEM) micrographs, gelatin-heparin immobilized PU nanofibers exhibited a smooth surface and a bead free structure that nanofibers distributed in the range of 300–1000 nm. The mechanical strength of constructs, swelling and biodegradation ratio, and drug release level illustrated higher values for oxygen plasma-treated samples compared with bilayered scaffolds. Cellular adhesion and biocompatibility ameliorated after plasma treatment. All the mentioned findings indicated the initial physicomechanical and biological potential of biomimetic PU-based fibers in the improvements of vascular scaffolds.

Bone defects arising from injury and/or disease are a common and debilitating clinical lesion. While the development of tissue microenvironments utilizing biomimetic constructs is an emerging approach for bone tissue engineering. In this context, bioactive glass nanoparticles (BGNPs) were embedded within polycaprolactone (PCL) scaffolds. The scaffolds exhibit an engineered unidirectional pore structure which are surface activated via oxygen plasma to allow immobilization of simvastatin (SIM) on the pore surface. Microscopic observation indicated the surface modification did not disturb the lamellar orientation of the pores improving the biomimetic formation of hydroxyapatite. Mathematically modelled release profiles reveal that the oxygen plasma pre-treatment can be utilized to modulate the release profile of SIM from the scaffolds. With the release mechanism controlled by the balance between the diffusion and erosion mechanisms. Computational modelling shows that Human Serum Albumin and Human α2-macroglobulin can be utilized to increase SIM bioavailability for cells via a molecular docking mechanism. Cellular studies show positive MG-63 cell attachment and viability on optimized scaffolds with alkaline phosphatase activity enhanced along with enhanced expression of osteocalcoin biomarker.

Forward osmosis (FO) process due to its potential in water desalination has attracted considerable attention. Although the FO process possesses numerous privileges like no requirement of external hydraulic pressure, it confronts some challenges. A major challenge is the development of high-performance FO membranes. In this study wa fabricated FO membranes with high water permeability and salt rejection utilizing a pressure-assisted self-assembly method. The supramolecular star polymers consisting of quaternary poly (2-(dimethylamino)ethyl methacrylate) and negatively charged blue lemon polyoxometalate (POM) (PDMAEMA@BL) was embedded into the graphene oxide (GO) active layer to construct physical crosslinking among GO nanosheets. The performance of membranes was analyzed by FO experiment to determination the water flux, reverse salt flux, and selectivity. Modified membranes showed significant augment in water flux in FO mode from 14.93 LMH in control polyamide TFC membrane to 37.26 in P@BL0.8 (0.8 ml of the 25%W/W PDMAEMA@BL). Likewise, the fouling properties of membranes were analyzed using sodium alginate (SA) organic foulant. As results showed, modified membranes performed better against fouling than conventional polyamide TFC membranes.

Tissue engineering scaffolds simulate extracellular matrixes (ECMs) to promote healing processes of damaged tissues. In this investigation, ECM were simulated by retinoic acid-loaded polyurethane-graphene oxide nanofibers to regenerate bone defects. Scanning electron microscopy (SEM) micrographs, Fourier transform infrared (FTIR) spectrum and X-ray diffraction (XRD) patterns proved the synthesis of graphene oxide (GO) nanosheets. SEM micrographs of nanofibers demonstrated through the formation of homogeneous and bead free fibrous scaffolds that the diameter of fibers were reduced by decreasing the applied voltage in an electrospinning process and the addition of GO. According to the results, the addition of GO to the polyurethane (PU) solution led to an increase in mechanical strength which is the most important parameter in the hard tissue repair. The GO-containing scaffolds showed an increased wettability, swelling, biodegradation and drug release level. Release behavior in nanocomposite scaffolds followed the swelling and biodegradation mechanisms, so osteogenic expression was possible by incorporating retinoic acid (RA) in PU-GO nanofibrous scaffolds. Biological evaluations demonstrated that composite scaffolds are biocompatible and support cellular attachment in which RA-loaded samples represented better cellular spreading. In brief, nanocomposite fibers showed desired that the physicochemical, mechanical and biological properties and synergic effects of GO and RA in osteogenic activity of MG-63 cells produced favorable constructs for hard tissue engineering applications.

Tissue engineering is a biotechnology that is used to develop biological substitutes to restore, maintain, or improve functions. Thus, the porous scaffolds are used to accommodate cells in tissue engineering. In this research, three dimensional (3D) bi-layered polyurethane (PU)-gelatin nanofibrous scaffolds were prepared by the electrospinning method, after which the capability of the released heparin as an anti-coagulation factor was evaluated. Electrospinning has been extensively investigated for the preparation of fibers that exhibit a high surface area to volume ratio. Results showed that scanning electron microscopy (SEM) micrographs exhibited a smooth surface as well as a highly porous and bead-free structure, in which fibers were distributed in the range of 100–600 nm. The modulus and ultimate tensile strength (UTS) decreased and increased, respectively, after crosslinking the reaction of polymers. This process also reduced swelling ratio, the hydrolytic biodegradation rate, and the release rate as a function of time. Moreover, an in vitro assay demonstrated that 3D nanofibrous scaffolds supported L929 fibroblast cell viability and that cells adhered and spread on the fibers. Based on the obtained results, the heparin-loaded electrospinning nanofibrous scaffolds have initial physicochemical and mechanical properties to protect neo-tissue formation.

There are many methods used to fabricate the scaffolds for tissue regeneration, among which freeze casting has attracted a great deal of attention due to the capability to create a unidirectional structure. In this study, polycaprolactone (PCL) scaffolds were fabricated by freeze-casting technology in order to create porous microstructure with oriented open-pore channels. To induce biomineralization, and to improve hydrophilicity and cell interactions, mussel-inspired polydopamine (PDA) was coated on the surface of the freeze-cast PCL constructs. Then, the synergistic effects of oriented microstructure and deposited layer on efficient reconstruction of injured bone were studied. Microscopic observations demonstrated that, the coated layer did not show any special change in lamellar microstructure of the scaffolds. Water-scaffold interactions were evaluated by contact angle measurements, and they demonstrated strong enhancement in the hydrophilicity of the polymeric scaffolds after PDA coating. Biodegradation ratio and water uptake evaluation confirmed an increase in the measured values after PDA precipitation. The biomineralization of the PDA-coated scaffolds was characterized by field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD). Obtained results confirmed biomineralization of the constructs after a 28-day immersion in a simulated body fluid (SBF) solution. Mechanical analysis demonstrated higher compressive strength after PDA coating. L929 fibroblast cell viability and attachment illustrated that PDA-coated PCL scaffolds are able to support cell adhesion and proliferation. The increased secretion of alkaline phosphatase (ALP) after culturing osteosarcoma cell lines (MG-63) revealed the initial capability of scaffolds to induce bone regeneration. Therefore, the PDA-coated scaffolds introduce a promising approach for bone tissue engineering application.

There have been several attempts to synthesis biodegradable polymeric constructs with adequate porous structures for soft connective tissues. In this study, randomly-oriented PLGA-gelatin nanofibrous scaffolds were synthesized by electrospinning method. We offered an appropriate solvent (2, 2, 2-trifluoroethanol) to dissolve both polymers for achieving a homogenous solution without inducing any toxic effects. The results confirmed the formation of high porous and bead free scaffolds, in which an increase in the injection rate slightly decreased the mechanical, swelling ratio and biodegradation behaviors. The modulus and tensile strength for the scaffolds with the injection rate of 0.2 ml/hr were 0.72 ±0.02 and 2.70 ±0.33, respectively. In addition, the evaluation of cell proliferation demonstrated that L929 fibroblast cells spread well on the scaffolds, indicating that they are able to support cell attachment. A possible chemical bond formation has been also suggested for the blending mixture of PLGA and gelatin molecules. Copyright © 2016 VBRI Press.