Incorporation of Functionalized Halloysite Nanotubes (HNTs) into Thin-Film Nanocomposite (TFN) Nanofiltration Membranes for Water Softening.

Incorporating nanoparticles (NPs) into the selective layer of thin-film composite (TFC) membranes is a common approach to improve the performance of the resulting thin-film nanocomposite (TFN) membranes. The main challenge in this approach is the leaching out of NPs during membrane operation. Halloysite nanotubes (HNTs) modified with the first generation of poly(amidoamine) (PAMAM) dendrimers (G1) have shown excellent stability in the PA layer of TFN reverse-osmosis (RO) membranes. This study explores, for the first time, using these NPs to improve the properties of TFN nanofiltration (NF) membranes. Membrane performance was evaluated in a cross-flow nanofiltration (NF) system using 3000 ppm aqueous solutions of MgCl2, Na2SO4 and NaCl, respectively, as feed at 10 bar and ambient temperature. All membranes showed high rejection of Na2SO4 (around 97-98%) and low NaCl rejection, with the corresponding water fluxes greater than 100 L m-2 h-1. The rejection of MgCl2 (ranging from 82 to 90%) was less than that for Na2SO4. However, our values are much greater than those reported in the literature for other TFN membranes. The remarkable rejection of MgCl2 is attributed to positively charged HNT-G1 nanoparticles incorporated in the selective polyamide (PA) layer of the TFN membranes.

Capsaicin-loaded alginate nanoparticles embedded polycaprolactone-chitosan nanofibers as a controlled drug delivery nanoplatform for anticancer activity.

Nanocarrier-based drug delivery systems have been designed into various structures that can effectively prevent cancer progression and improve the therapeutic cancer index. However, most of these delivery systems are designed to be simple nanostructures with several limitations, including low stability and burst drug release features. A nano-in-nano delivery technique is explored to address the aforementioned concerns. Accordingly, this study investigated the release behavior of a novel nanoparticles-in-nanofibers delivery system composed of capsaicin-loaded alginate nanoparticles embedded in polycaprolactone-chitosan nanofiber mats. First, alginate nanoparticles were prepared with different concentrations of cationic gemini surfactant and using nanoemulsion templates. The optimized formulation of alginate nanoparticles was utilized for loading capsaicin and exhibited a diameter of 19.42 ± 1.8 nm and encapsulation efficiency of 98.7 % ± 0.6 %. Likewise, blend polycaprolactone-chitosan nanofibers were prepared with different blend ratios of their solutions (i.e., 100:0, 80:20, 60:40) by electrospinning method. After the characterization of electrospun mats, the optimal nanofibers were employed for embedding capsaicin-loaded alginate nanoparticles. Our findings revealed that embedding capsaicin-loaded alginate nanoparticles in polycaprolactone-chitosan nanofibers, prolonged capsaicin release from 120 h to more than 500 h. Furthermore, the results of in vitro analysis demonstrated that the designed nanoplatform could effectively inhibit the proliferation of MCF-7 human breast cells while being nontoxic to human dermal fibroblasts (HDF). Collectively, the prepared nanocomposite drug delivery platform might be promising for the long-term and controlled release of capsaicin for the prevention and treatment of cancer.

A hydrogel-fiber-hydrogel composite scaffold based on silk fibroin with the dual-delivery of oxygen and quercetin.

Supplying sufficient oxygen within the scaffolds is one of the essential hindrances in tissue engineering that can be resolved by oxygen-generating biomaterials (OGBs). Two main issues related to OGBs are controlling oxygenation and reactive oxygen species (ROS). To address these concerns, we developed a composite scaffold entailing three layers (hydrogel-electrospun fibers-hydrogel) with antioxidant and antibacterial properties. The fibers, the middle layer, reinforced the composite structure, enhancing the mechanical strength from 4.27 ± 0.15 to 8.27 ± 0.25 kPa; also, this layer is made of calcium peroxide and silk fibroin (SF) through electrospinning, which enables oxygen delivery. The first and third layers are physical SF hydrogels to control oxygen release, containing quercetin (Q), a nonenzymatic antioxidant. This composite scaffold resulted in almost more than 40 mmHg of oxygen release for at least 13 days, and compared with similar studies is in a high range. Here, Q was used for the first time for an OGB to scavenge the possible ROS. Q delivery not only led to antioxidant activity but also stabilized oxygen release and enhanced cell viability. Based on the given results, this composite scaffold can be introduced as a safe and controllable oxygen supplier, which is promising for tissue engineering applications, particularly for bone.

Surface Heparinization of a Magnesium-Based Alloy: A Comparison Study of Aminopropyltriethoxysilane (APTES) and Polyamidoamine (PAMAM) Dendrimers.

Magnesium (Mg)-based alloys are biodegradable metallic biomaterials that show promise in minimizing the risks of permanent metallic implants. However, their clinical applications are restricted due to their rapid in vivo degradation and low surface hemocompatibilities. Surface modifications are critically important for controlling the corrosion rates of Mg-based alloys and improving their hemocompatibilities. In the present study, two heparinization methods were developed to simultaneously increase the corrosion resistance and hemocompatibility of the AZ31 Mg alloy. In the first method, the surface of the AZ31 alloy was modified by alkali-heat treatment and then aminolyzed by 3-amino propyltriethoxy silane (APTES), a self-assembly molecule, and heparin was grafted onto the aminolyzed surface. In the second method, before heparinization, polyamidoamine dendrimers (PAMAM4-4) were grafted onto the aminolyzed surface with APTES to increase the number of surface functional groups, and heparinization was subsequently performed. The presence of a peak with a wavelength of about 1560 cm-1 in the FTIR spectrum for the sample modified with APTES and dendrimers indicated aminolysis of the surface. The results indicated that the corrosion resistance of the Mg alloy was significantly improved as a result of the formation of a passive layer following the alkali-heat treatment. The results obtained from a potentiodynamic polarization (PDP) test showed that the corrosion current in the uncoated sample decreased from 25 µA to 3.7 µA in the alkali-heat-treated sample. The corrosion current density was reduced by 14 and 50 times in samples treated with the self-assembly molecules, APTES and dendrimers, respectively. After heparinization, the clotting time for pristine Mg was greatly improved. Clotting time increased from 480 s for the pristine Mg sample to 630 s for the APTES- and heparin-modified samples and to 715 s for the PAMAM- and heparin-modified samples. Cell culture data showed a slight improvement in the cell-supporting behavior of the modified samples.

Hybrid electrospun scaffolds based on polylactic acid/ PAMAM dendrimer/gemini surfactant for enhancement of synergistic antibacterial ability for biomedical application.

Hybrid electrospun scaffolds based on poly (L-lactic acid) (PLLA)/poly (amidoamine) (PAMAM-G2) dendrimer/gemini surfactant were fabricated for the enhancement of synergistic antibacterial activities. The second generation of poly (amidoamine) (PAMAM-G2) and cationic gemini surfactant were utilized to functionalize the optimum electrospun scaffolds. The gelatination process was utilized to improve the wettability of PLLA scaffolds to extend cell attachment and cell proliferation. PLLA nanofibrous scaffolds were characterized by energy dispersion x-ray, scanning electron microscopy images, mechanical properties, water contact angle, Fourier transform infrared spectroscopy, zeta potential and antibacterial assessment.In vitrocell biocompatibility was evaluated by 3-(4, 5- dimethylthiazoyl-2-yl)-2, 5-diphenyltetrazolium bromide assay and morphology of PC-12 cells cultured on hybrid nanofibrous scaffolds and gelatinized ones. The results indicated that the optimum scaffolds could successfully modify the characteristics of PLLA scaffolds leading to much more appropriate physical and chemical properties. In addition, gelatinized nanofibrous scaffolds reveal more wettability enhancing cell attachment and proliferation. Furthermore, using poly (amidoamine) (PAMAM-G2) and gemini surfactant reveals synergetic antibacterial activity due to the competition between both cationic groups of PAMAM and gemini surfactant. Finally, improved cell adhesion and cell viability on modified scaffolds were confirmed. These favorable properties give a chance for these scaffolds to be used in a wide variety of biomedical applications.

Cationic gemini surfactant properties, its potential as a promising bioapplication candidate, and strategies for improving its biocompatibility: A review.

Gemini surfactants consist of two cationic monomers of a surfactant linked together with a spacer. The specific structure of a cationic gemini surfactant is the reason for both its high surface activity and its ability to decrease the surface tension of water. The high surface activity and unique structure of gemini surfactants result in outstanding properties, including antibacterial and antifungal activity, anticorrosion properties, unique aggregation behaviour, the ability to form various structures reversibly in response to environmental conditions, and interactions with biomacromolecules such as DNA and proteins. These properties can be tailored by selecting the optimal structure of a gemini surfactant in terms of the nature and length of its alkyl substituents, spacer, and head group. Additionally, regarding their properties, comparison with their monomeric counterparts demonstrates that gemini surfactants have higher performance efficacy at lower concentrations. Hence, less material is needed, and the toxicity is lower. However, there are some limitations regarding their biocompatibility that have led researchers to develop amino acid-based and sugar-based gemini surfactants. Owing to their remarkable properties, cationic gemini surfactants are promising candidates for bioapplications such as drug delivery systems, gene carriers, and biomaterial surface modification.

Hemostatic Electrospun Nanocomposite Containing Poly(lactic acid)/Halloysite Nanotube Functionalized by Poly(amidoamine) Dendrimer for Wound Healing Application: In Vitro and In Vivo Assays.

The main challenge in treating injuries is excessive bleeding whereas intervention is required if the body's hemostatic systems fail to control the bleeding. Herein, a novel nanocomposite consisting of poly(lactic acid) (PLA) and poly(amidoamine) (PAMAM) dendrimer functionalized halloysite nanotube (HNT) with a highly porous structure via electrospinning is developed. HNT is functionalized by PAMAM via divergent synthetic routes from zero to third-generation numbers. The effect of different percentages and generation numbers of PAMAM dendrimer (G1, G2, and G3) functionalized HNT on PLA is studied using physicochemical nanocomposite characteristics. These resultant nanocomposites provide a nanofibrous structure with appropriate physicochemical characteristics such as mechanical properties, surface wettability, and water permeability. The hemostatic assays indicate that nanocomposite with PAMAM G3 functionalized HNT have the quickest blood clotting time due to the abundant amino functional group. Furthermore, the nanocomposites with 10 wt% of nanoparticles significantly promote cellular behavior in vitro. The in vivo study demonstrates that PLA/PAMAM G3 functionalized HNT promotes angiogenesis, collagen deposition, and re-epithelialization in the wound sites of the rat model, as well as inhibiting inflammatory response. The findings indicate that nanofibrous structure and the presence of dendrimer functionalized HNT have a synergetic effect on the enhanced nanocomposite wound healing performance.

Synthesis and characterization of tetraethylene pentamine functionalized MIL-101(Cr) for removal of metals from water.

PURPOSE: Metal contamination in water is a worldwide persistent problem. We developed a nano-adsorbent, TEPA-MIL-101(Cr) that exhibits effective removal of heavy metals from real water samples. METHODS: MIL-101(Cr) was synthesized under solvo-thermal condition. Then MIL-101(Cr) was dehydrated and degassed at high temperature under vacuum to generate the coordinately unsaturated sites which are used for tetraethylene pentamine (TEPA) grafting. The structures, morphologies, and compositions of the sorbents have been characterized. Langmuir and Freundlich isotherm models were applied for describing the adsorption process onto TEPA-MIL-101(Cr). RESULTS: The successful grafting of TEPA on MIL-101(Cr) was verified by Fourier transform infrared. The results of X-ray diffraction, scanning electron microscopy, and CHN analysis show that the structure of TEPA-MIL-101(Cr) retains the original structure of MIL-101(Cr). Thermogravimetric analysis indicates thermo-stability of the adsorbent up to 300 °C. Optimal conditions for adsorption were determined as pH = 6.5 and contact time = 1 h. The adsorption capacities of TEPA-MIL-101(Cr) for Pb(II), Cu(II), Cd(II), and Co(II) from aqueous samples were 227.5, 217.7, 221.4, and 215.6 mg/g respectively, which is on average more than 8 times that of MIL-101(Cr). Analysis of Langmuir and Freundlich models for describing the adsorption isotherms of TEPA-MIL-101(Cr) reveals that the metal ions were absorbed onto TEPA-MIL-101(Cr) by a favorable physical absorption process. CONCLUSIONS: TEPA-MIL-101(Cr) was synthesized successfully by a simple, and cost-effective method. The removal efficiency of TEPA-MIL-101(Cr) for the metal ions achieved more than 95 % in real water samples, which in addition to its thermal stability character make it a promising candidate for water treatment purposes.

Ionic conductive nanocomposite based on poly(l-lactic acid)/poly(amidoamine) dendrimerelectrospun nanofibrous for biomedical application.

The modification of poly (l-lactic acid) (PLLA) electrospun nanofibrous scaffolds was carried out by blending with second-generation poly amidoamine (PAMAM) for enhancement of their ionic conductivity. The samples containing PLLA and various amounts of PAMAM (1%, 3%, 5%, and 7% by wt.) were fabricated by electrospinning techniques. The electrospun fibers were characterized using scanning electron microscopy (SEM), porosity, Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry, contact angle measurement, water uptake measurement, mechanical properties, and electrical properties. Furthermore,in vitrodegradation study and cell viability assay were investigated in biomaterial applications. Creating amide groups through aminolysis reaction was confirmed by FTIR analysis successfully. The results reveal that adding PAMAM caused an increase in fiber diameter, crystallinity percentage, hydrophilicity, water absorption, elongation-at-break, and OE-mesenchymal stem cell viability. It is worth mentioning that this is the first report investigating the conductivity of PLLA/PAMAM nanofiber. The results revealed that by increasing the amount of PAMAM, the ionic conductivity of scaffolds was enhanced by about nine times. Moreover, the outcomes indicated that the presence of PAMAM could improve the limitations of PLLA like hydrophobicity, lack of active group, and poor cell adhesion.

Treatment with edaravone improves the structure and functional changes in the hippocampus after chronic cerebral hypoperfusion in rat.

This study aimed to find out cellular and electrophysiological effects of the edaravone (EDR) administration following induction of vascular dementia (VaD) via bilateral-carotid vessel occlusion (2VO). The rats were randomly divided into control, sham, 2VO + V (vehicle), and 2VO + EDR groups. EDR was administered once a day from day 0-28 after surgery. The passive-avoidance, Morris water-maze, and open-field tests were used for evaluation of memory, locomotor, and anxiety. The field-potential recording was used for assessment of electrophysiological properties of the hippocampus; and after sacrificing, the cerebral hemispheres were removed for stereological study and evaluation of MDA levels. The long-term potentiation (LTP), paired-pulse ratio (PPR), and input-output (I/O) curves were evaluated as indexes for long-term and short-term synaptic plasticity, and basal-synaptic transmission (BST), respectively. The 2VO led to increases in MDA level with considerable neuronal loss and decreases in the volume of the hippocampus, along with a reduction in the BST and LTP induction which was associated with a decrement in PPR and ultimate loss in memory with higher anxiety behavior. However, administration of EDR caused a decline in MDA and prevented the neural loss and volume of the hippocampus, rescued BST and LTP depression, improved memory and anxiety without any effects on PPR. Therefore, most likely through the improvement of MDA level, and the hippocampal cell number and volume, EDR leads to recovery of synaptic plasticity and behavioral performance. Because of the LTP rescue, without recovery of PPR, it is likely that the EDR improved LTP through the post-synaptic neurons.

Amine-terminated dendritic polymers as promising nanoplatform for diagnostic and therapeutic agents' modification: A review.

It is often challenging to design diagnostic and therapeutic agents that fulfill all functional requirements. So, bulk and surface modifications as a common approach for biomedical applications have been suggested. There have been considerable research interests in using nanomaterials to the prementioned methods. Among all nanomaterials, dendritic materials with three-dimensional structures, host-guest properties, and nano-polymeric dimensions have received considerable attention. Amine-terminated dendritic structures including, polyamidoamine (PAMAM), polypropyleneimine (PPI), and polyethyleneimine (PEI), have been enormously utilized in bio-modification. This review briefly described the structure of these three common dendritic polymers and their use to modify diagnostic and therapeutic agents in six major applications, including drug delivery, gene delivery, biosensor, bioimaging, tissue engineering, and antimicrobial activity. The current review covers amine-terminated dendritic polymers toxicity challenging and improvement strategies as well.

Fabrication and Characterization of Lignin/Dendrimer Electrospun Blended Fiber Mats.

Blending lignin as the second most abundant polymer in Nature with nanostructured compounds such as dendritic polymers can not only add value to lignin, but also increase its application in various fields. In this study, softwood Kraft lignin/polyamidoamine dendritic polymer (PAMAM) blends were fabricated by the solution electrospinning to produce bead-free nanofiber mats for the first time. The mats were characterized through scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, zeta potential, and thermogravimetry analyses. The chemical intermolecular interactions between the lignin functional groups and abundant amino groups in the PAMAM were verified by FTIR and viscosity measurements. These interactions proved to enhance the mechanical and thermal characteristics of the lignin/PAMAM mats, suggesting their potential applications e.g. in membranes, filtration, controlled release drug delivery, among others.

The odour assessment of thyme essential oils in electrospun fibre mat with a virtual sensor array data and its relation to antibacterial activity.

Aims: The ability of a single-sensor gas diagnosis device (SSGDD) as a virtual sensor array data to appraise thyme essential oils (TEO) based on its quantitatively release rate from nanofibres was aimed.Methods: To form nylon 6 fragrant electrospun nanofibre, TEO was added as a natural antibacterial substance under homogeniser to make a stable emulsion.Results: The optimised nanofibre inactivated against Escherichia Coli and Staphylococcus Aureus bacteria up to >75% at once and to > 41.9% over 2-weeks period. Moreover, large differences in sensor responses to samples with experimental variables (percent TEO and storage time) and different odour intensity exist which correctly classified by discriminant function analysis.Conclusions: Odour intensity as an accessible incubator evinces the nanofibres efficiency which correlated to the antibacterial activity. With applying SSGDD technique as a quantified subjective solution, carefully odour assessment is possible and prepared mats could be demonstrated as a face-masks' promising candidate.

Fabrication of electrospun ibuprofen-loaded poly(vinyl alcohol)/hyper-branched poly(ethylenimine) fibers and their release behaviors.

A novel transdermal drug delivery system for the release of ibuprofen (IBU) was fabricated via poly(vinyl alcohol)/hyper-branched poly(ethylene imine) (PVA/PEI) nanofibrous membranes. Hence, PVA/PEI solutions were electrospun at different PVA/PEI mass ratios of 100/0, 85/15, 75/25, and 65/35. SEM observations illustrated that the diameters of collected fibers to be 125-161 nm. Fourier-transform infrared and differential scanning calorimetric characterizations were used to examine microstructural changes of fibers. In vitro drug release revealed that the amount of drug loaded in PVA/PEI fibers increased by enhancing PEI content due to abundant amine terminated groups as well as hollow interior between branches. The maximum concentration of released drug equal to 130.69 mg/L was achieved for PVA/PEI (75/25) fibers, which is about 2.5 times higher than drug-loaded PVA fibers. An increase of 34% in drug release characteristic of fibrous structure comparing with as-cast film was also obtained at 24 h of immersion time. The decreased release rate of IBU was shown for drug-loaded PVA and PVA/PEI fibers heat-treated at 140 °C and 120 °C, respectively. By assessing drug release mechanism through so-called Peppas kinetic model, it was found that heat treatment changed release mechanism from swelling-controlled to diffusion-controlled for drug-loaded PVA/PEI fibers. Overall, IBU-loaded PVA/PEI fibrous membrane presents a substantial potential for drug delivery systems with anti-inflammation and analgesic-eluting applications.

Amine-terminated dendritic polymers as a multifunctional chelating agent for heavy metal ion removals.

In this study, amine-terminated hyperbranched PAMAM (polyamidoamine) polymer (AT-HBP) was synthesized as a multifunctional chelating agent to remove two heavy metal ions (Cr(III) and Cu(II)) from the simulated wastewater solutions. The AT-HBP was characterized by Fourier transformed infrared (FTIR), dynamic light scattering (DLS), and proton nuclear magnetic resonance (1H NMR) analysis. The removal process was carried out in two different methods, centrifuged process and ultrafiltration. The concentration of heavy metal ions before and after removal was measured by inductively coupled plasma (ICP) instrument. The removal processes were evaluated by changing different parameters such as solution pH, AT-HBP dosage, and metal ion concentration. To evaluate the extend of binding of heavy metal ions in the presence of AT-HBP the presence of salt in the solution was also examined on the performance of the removal system. The overall results indicated that removal percentages higher than 98% for Cr(III) and 86% for Cu(II) were achieved for heavy metal concentrations of 100 mg/L for both removal process methods. Furthermore, the function of second generation of polypropylenimine (PPI) was compared to AT-HBP. The results reveal that the removal of Cr(III) and Cu(II) ions by AT-HBP were approximately 20% and 10% higher compared to PPI, respectively. Finally, hyperbranched dendritic polymer with lower expenses to synthesize compared to dendrimer underlined favorable properties as a multifunctional chelating agent and enhancement of ultrafiltration process for wastewater treatment. Graphical abstract.

Electrospun nanofibers comprising of silk fibroin/gelatin for drug delivery applications: Thyme essential oil and doxycycline monohydrate release study.

In this study, a nanofibrous electrospun substrate based on the silk fibroin (SF) and gelatin (GT) polymers were prepared and evaluated. The SF/GT blended solutions were prepared with various ratios of GT in formic acid and electrospun to obtain bead-free fibers. Results showed that addition of GT to SF increased nanofiber's diameter, bulk hydrophilicity, surface wettability, mass loss percentage, but decreased Young's modulus, tensile strength, and porosity of the SF/GT mats. According to the obtained results, the mat containing 10% of GT was selected as the optimized mat for further studies and loaded with thyme essential oil (TEO) and doxycycline monohydrate (DCMH) as the antibacterial agents. Release studies showed a burst release of TEO from the mat within the first 3 h, while the DCMH had a sustained release during 48 h. In comparison to the TEO-loaded mat, the DCMH-loaded one showed larger inhibition zones against Staphylococcus aureus and Klebsiella pneumoniae bacteria. Meanwhile, cellular studies using mouse fibroblast L929 cells showed excellent cell-compatibility of TEO- and DCMH-loaded mats. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1092-1103, 2018.

QSAR Modeling of COX -2 Inhibitory Activity of Some Dihydropyridine and Hydroquinoline Derivatives Using Multiple Linear Regression (MLR) Method.

COX-2 inhibitory activities of some 1,4-dihydropyridine and 5-oxo-1,4,5,6,7,8-hexahydroquinoline derivatives were modeled by quantitative structure-activity relationship (QSAR) using stepwise-multiple linear regression (SW-MLR) method. The built model was robust and predictive with correlation coefficient (R2) of 0.972 and 0.531 for training and test groups, respectively. The quality of the model was evaluated by leave-one-out (LOO) cross validation (LOO correlation coefficient (Q2) of 0.943) and Y-randomization. We also employed a leverage approach for the defining of applicability domain of model. Based on QSAR models results, COX-2 inhibitory activity of selected data set had correlation with BEHm6 (highest eigenvalue n. 6 of Burden matrix/weighted by atomic masses), Mor03u (signal 03/unweighted) and IVDE (Mean information content on the vertex degree equality) descriptors which derived from their structures.

Preparation and catalytic activity of bone-char ash decorated with MgO - FeNO3 for ozonation of reactive black 5 dye from aqueous solution: Taguchi optimization data.

Reactive dye is one of the most applicable dyes in textile industries which its release to the water bodies creates a concern for environmentalists. Here, in this data article a bone-char (BC) ash decorated with MgO-FeNO3 for removing reactive black 5 (RB5) dye in a catalytic ozonation process (COP) system. Operational parameters data such as initial RB5 concentration, pH, catalyst dosage, and reaction time were optimized using Taguchi method. The optimal conditions for initial RB5 concentration, pH, catalyst dosage, and reaction time were determined 10 mg/L, 10, 0.1 g/L, and 15 min, respectively. Data of Taguchi optimization tests indicated that the initial RB5 concentration had a significant influence on RB5 removal efficiency (54.03%) during the catalytic ozonation process, and reaction time had lower contribution (2.04%).