Search

Administration of temperature-responsive drug carriers that release anticancer drugs at high temperatures can benefit hyperthermia therapies because of the synergistic effect of anticancer drug molecules and high temperature on killing the cancer cells. In this study, we design and characterize a new temperature-responsive nanocarrier based on a naturally occurring and biocompatible clay mineral, halloysite nanotubes. Poly(N-isopropylacrylamide) brushes were grown on the surface of halloysite nanotubes using a combination of mussel-inspired dopamine polymerization and surface-initiated atom transfer radical polymerization. The chemical structure of the hybrid materials was investigated using X-ray photoelectron spectroscopy, thermogravimetric analysis and energy-dispersive X-ray spectroscopy. The hybrid material was shown to have a phase transition temperature of about 32 °C, corresponding to a 40 nm thick polymer layer surrounding the nanotubes. Cell studies suggested that grafting of poly(N-isopropylacrylamide) brushes on the polydopamine-modified halloysite nanotubes suppresses the cytotoxicity caused by the polydopamine interlayer and drug release studies on nanotubes loaded with doxorubicin showed that thanks to the poly(N-isopropylacrylamide) brushes a temperature-dependent drug release is observed. Finally, a fluorescent dye molecule was covalently attached to the polymer-grafted nanotubes and stimulated emission depletion nanoscopy was used to confirm the internalization of the nanotubes in HeLa cells.

Polyurethanes (PUs) microstructure and characteristics is strongly affected by microphase separation that arises from the thermodynamic immiscibility between the hard and soft segments. The extent of phase separation as well as the morphology and size of the separated phase governs their mechanical, electrical, thermal, and functional properties. This review: (1) provides an insight into how phase separation affects PU properties, (2) explains methods used to study PU phase separation. We review approaches from the simplest one, that is, the transparency measurement, to the more advanced methods including the spectroscopic techniques (infrared, nuclear magnetic resonance spectroscopies and X-ray scattering), rheological instruments ( rheometrics mechanical spectrometer), and thermal analyses (differential scanning calorimetry). We also discuss the theoretical calculations and the molecular modeling used to study PU phase separation.

Different types of chain extenders in the synthesis of polyurethanes affect its structural, mechanical, and rheological properties. Effects of chain extender length, functionality, and molar ratio of the reactants on different properties of polyurethane elastomers based on poly (oxytetramethylene)glycol as the soft segment and toluene diisocyanate as the hard segment were investigated. Polyurethane samples were synthesized using different chain extenders including glycerol as the trifunctional and 1,2-propanediol, 1,4-butanediol, and 1,6-hexanediol as the bi-functional hydroxyl-containing chemicals. Fourier-transform infrared spectroscopy, X-ray diffraction, rheomechanical analysis, dynamic mechanical thermal analysis, differential scanning calorimetry, and stress–strain analysis were used for characterization of the products. By phase separation of the hard and soft segments, two different glass transition temperatures were observed. Increasing phase separation and degree of hydrogen bonding between the chain extender and diisocynates in the hard segments were resulted in higher mechanical properties. With increasing the amount of hard segment, a higher polymer toughness is determined due to higher degree of hydrogen bonding.

The development of stimuli-responsive drug nanocarriers is an increasingly important area in nanomedicine because efficient delivery of toxic drugs to targeted tissues minimizes side effects. The specific objective of this study was to synthesize and characterize a novel pH-responsive drug carrier based on halloysite nanotubes for the controlled release of the anticancer drug doxorubicin. Poly(N,N-dimethylaminoethyl methacrylate) brushes were grafted from the surface of halloysite nanotubes using the combination of mussel-inspired polydopamine surface modification and activators regenerated by electron transfer in atom transfer radical polymerization. The chemical structure and morphology of the modified halloysite nanotubes were investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermal gravimetric analysis as well as scanning and transmission electron microscopies. Dynamic light scattering and zeta potential analysis were carried out to evaluate the pH-responsivity of the functionalized halloysite nanotubes. The results of the drug loading and release study of pristine and functionalized halloysite nanotubes showed that grafting of poly(N,N-dimethylaminoethyl methacrylate) brushes on the polydopamine-modified halloysite nanotubes surface leads to a drastic increase in doxorubicin loading capacity and a highly pH-sensitive release behaviour. Less than 10 % of the loaded doxorubicin was released from poly (N,N-dimethylaminoethyl methacrylate)-grafted halloysite nanotubes at pH 7.4 after 24 h; in contrast, at pH 5.5 there was a continuous release of doxorubicin totalling 13 % in the first 30 min, i.e. lower than for the pristine halloysite nanotubes (32 %), but reaching 48 % after 24 h. Poly (N,N-dimethylaminoethyl methacrylate)-grafted halloysite nanotubes can hence be considered as a potential candidate for delivering highly toxic drug molecules to the acidic target sites.

To understand the role of mixed soft segments (PCL/PTHF) on the microphase separation of TPUs, thermodynamic calculations, molecular dynamics (MD) simulation and experimental approaches were used. With the use of three-component Flory–Huggins model, interaction parameter and solubility parameters, the free energy of mixing of soft segments and hard segment was investigated. MD simulation was also used to evaluate different types of hydrogen bonding and segmental interactions at atomic levels. To this end, the extent of microphase separation (αsep), state of hydrogen bonding, segment melting enthalpies, crystallization process time and temperature, morphology of soft and hard phases and mechanical properties were fully characterized by ATR-FTIR, DSC, TEM, RMS and tensile techniques. Isothermal and non-isothermal examinations have shown that using mixed soft segments accelerates the microphase separation process comparing samples containing one type of polyols. Mechanical properties data showed that using mixed soft segments disallowed early failure and TPU with extreme enhanced elongation at break and toughness could be obtained.

Developing high conductive porous electrode materials is a critical challenge to increase the electrochemical performance of supercapacitors. In this work carbon-based graphene oxide was functionalized by 2,4-diaminopyrimidine ligand (rGO-2,6-DP) and then in the presence of triethyl amine, CoI2 was linked to the functionalized graphene oxide structure (Co-rGO) and characterized by XPS, XRD, TEM, SEM, FT-IR, and EDX techniques. To improve the electrochemical efficiency in terms of specific capacity and energy density, porous Co-rGO was electro-synthetically blended with conducting polymer of POAP (Co-rGO-POAP) as high conductive electrode material. Cyclic voltammetry tests were carried out in three-electrode system and showed high electrochemical potential with long cycle life and specific capacitance of 944 at 1 A g−1 in aqueous environment. The charge–discharge results represented superior efficiency of synthesized Co-rGO-POAP nanocomposite as an outstanding electrode in supercapacitor. Also, Ragone plot described improved energy densities at power densities while energy density obtained as 131.2 Wh kg−1 at power density of 500 W kg−1. Electrochemical impedance spectroscopy showed that the synergistic effect of Co-rGO and conducting polymer enhanced electrochemical features through the facilitating electron delivery and reducing electron resistance. This investigation open a new strategy to use beneficial of both metal and carbon-based materials to use in energy storage devices.

Carbon-based fillers were used as reinforcement for thermoplastic polyurethane (TPU) matrix. For the first time the rheological behavior of hybrid polyurethane nanocomposite has been surveyed and the formation of continuous network of two carbon-based fillers has been reported. Nanocomposites containing multi-walled carbon nanotubes (MWCNTs), carbon fibers (CFs) and MWCNTs/CFs were prepared through melt compounding method and evaluated with various techniques including microscopy, spectroscopy and comprehensive rheological analyses. Linear rheological methods such as strain, frequency, temperature and time sweeps, and non-linear flow curve method were adopted to study the viscoelastic properties of the nanocomposites. Attenuated total reflectance Fourier transform infrared spectroscopy showed that MWCNTs had higher interactions with TPU hard segments due to their high aspect ratio, whereas CFs had low interactions. In hybrid nanocomposite, a continuous network of carbon-based fillers was created which acted as a surface for nucleation of hard segment and induced the highest influence on viscoelastic behavior of resulting nanocomposites. Based on the microscopy analyses, existence of co-continuous morphology was observed for hybrid nanocomposite. Moreover, relationship between the structure of nanofillers and formation of microphase separated domains at various nanofiller contents was discussed. At first, the rheological behavior of each nanocomposite was separately studied. To conclude, the results corroborated that CFs and MWCNTs formed a network of carbon-based structure and changed the viscoelastic properties of hybrid nanocomposites.

Cross-linked poly(acrylic acid) nanoparticles were synthesized via distillation precipitation polymerization of acrylic acid and ethylene glycol dimethacrylate withdifferent molar ratios. Spherical nanoparticles with diameters between 75 and 122 nm were synthesized and exhibited temperature and pH-responsive behaviors. However, this behavior was less pronounced for samples with higher cross-linking degrees. The potential of all nanoparticles as carriers for controlled release of doxorubicin (DOX) anti-cancer drug was examined at pH values of 1.2, 5.3 and 7.4. An obvious alleviation in burst release behavior and the amount of cumulative drug release was seen for all nanoparticles as the pH of the medium and the cross-linking degree of nanoparticle increased. Also kinetics of drug release was studied using mathematical models of zero-order, first-order, Higuchi, Korsmeyer-Peppas and Hixson-Crowell, where Higuchi and Korsmeyer-Peppas models best defined the kinetics of drug release.

We are reporting on well-designed single-layered and gradient concentration triple-layered microwave-absorbing composites based on functionalized reduced graphene oxide (FRGO). The RGO-[Co2L2Cl3]Cl, called FRGO, was fabricated through systematic experimental efforts by the covalent attachment of the 2,6-diamino-3-[(2-carboxylicacid) phenylazo]-pyridine (L)/Cobalt (Co) complex with graphene oxide (GO) functionalities. The formation of FRGO was proven by a series of characterization techniques, such as XPS, FTIR, XRD, Raman spectroscopy, FESEM, and TEM. The consideration of RGO-[Co2L2Cl3]Cl as a highly efficient microwave-absorbing material is a result of its magnetoelectric synergistic effect, impedance match, and multiple scattering. The maximum reflection loss (RL) of single-layered an RGO-[Co2L2Cl3]Cl/epoxy resin composite can reach −16.32 dB at 8.69 GHz, which corresponds to a composite with 30 wt % absorber loading and a thickness of 4.5 mm. For the triple-layered composite with increasing mass percentage (10–20–30 wt %) of RGO-[Co2L2Cl3]Cl in the direction of microwave propagation, the maximum reflection loss value of −34.9 dB can be achieved at 10.69 GHz, with a coating layer thickness of 4.5 mm. The result demonstrates that the RGO-[Co2L2Cl3]Cl/epoxy resin composites of both models can be ideal microwave-absorbing candidates for application in the X-band.

Thermoplastic polyurethanes (TPUs) based on soft segments with varying molecular weight and molecular architecture show interesting micro-phase separation, thermal, morphological, molecular dynamics, and rheological properties. In the present study, TPUs based on two types of polyols, i.e., poly(tetramethylene ether) (1000 and 2000 g/mol) and polycaprolactone (500 and 2000 g/mol), were synthesized. This work has aimed to combine synthetic procedures, physical–chemistry calculations, and molecular dynamics simulation to study the effect of structure and molecular weight of the soft segments on TPU properties. Extent and kinetics of micro-phase separation were quantified with several methods such as spectroscopy, time-sweep rheological analysis, product of interaction parameter and degree of polymerization (χN), thermal analysis, compressible regular solution model, molecular dynamics, and microscopy. The results showed that high molecular weight polyether- and low molecular weight polyester-based synthesized TPUs have the highest and the lowest micro-phase separations, respectively. Moreover, in each class of polyol, the degree of micro-phase separation was concurrently increased with soft-segment block length. However, competition between enthalpic and entropic factors in the study of the polyols led to different results by various methods. Moreover, from the mechanical properties viewpoint, ester-based TPUs showed higher Young’s modulus and lower elongation-at-break compared to ether-based counterparts.

Background In this study, the ability of antimicrobial photodynamic therapy (aPDT) as a treatment approach and adjuvant therapy using curcumin-poly (lactic-co-glycolic acid) nanoparticles (Cur@PLGA-NPs) to inactivate Coronavirus disease 2019 (COVID-19) in plasma was investigated. Furthermore, to verify whether the quality requirement of aPDT-treated plasma is acceptable, the differences of the levels of clotting factors, total plasma proteins, and anti-A and/or anti-B antibodies titrations in plasma of patient before and after aPDT treatment were investigated. Materials and Methods Cur@PLGA-NPs was synthesized using Electrospinning process and characterized by different analysis including Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and Fourier Transform Infrared (FTIR) spectroscopy assays. The presence of the SARS-CoV-2 in the plasma samples of patients suspected of having COVID-19 was confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR) assay. Then, the treated plasma samples with Cur@PLGA-NPs plus blue laser were exposed to Vero cells. Eventually, cell cytotoxicity and apoptotic effects of treated Vero cells were evaluated. Levels of clotting factors including prothrombin time (PT) and activated partial thromboplastin time (APTT), total plasma proteins, and anti-A and/or anti-B antibodies measurements were performed using the coagulometer, method of Bradford, and titration procedure, respectively. Results The presence of SARS-CoV-2 was positive in 84.3 % of samples. Different concentrations of Cur@PLGA-NPs (3, 5, 7, and 10 % wt.), the irradiation times of blue laser (1, 3, and 5 min), and aPDT with the maximum dosed of blue laser light (522.8 J/cm2) plus 10 % wt. Cur@PLGA-NPs had no cytotoxicity. Although there were significant cell degradation and apoptotic effects in treated Vero cells with treated plasma using 10 % wt. Cur@PLGA-NPs, and a blue laser at an energy density of 522.8 J/cm2, no visible changes in cells and apoptosis were observed following aPDT. Total plasma protein content, PT, APTT, and anti-A and/or anti-B antibodies titers showed no significant changes (P > 0.05 for all comparisons) in treated plasma as compared to untreated plasma. Conclusion aPDT exhibited in vitro anti-COVID-19 activities in the treated plasma containing SARS-COV-2 without Vero cell apoptosis and any adverse effects on plasma quality in aPDT-exposed plasma.

Composition of polymers and choosing the type of solvents in electrospinning systems is of great importance to achieve a mat with optimal properties. In this work, with emphasizing the influence of a novel solvent system, an electrospun wound dressing was designed in four steps. Firstly, to study the effect of polymer-solvent interactions and electrospinning distance, a constant amount of polycaprolactone (PCL) was dissolved at different compositions of formic acid (FA)/dichloromethane (DCM) and was electrospun at different distances. The composition of 80FA/20DCM and distance of 15 cm were selected as optimal conditions by lowest average diameter of fibers and simultaneously good surface uniformity. In the second step, the concentration of PCL was considered variable to achieve the lowest diameter of fibers. Finally, in the third and fourth steps, different concentrations of chitosan (CN) and constant dosage of Melilotus officinalis (MO) extract were added to the solution. The extract contained fibers had a mean diameter of 275 ± 41 nm which is in the required condition for wound caring. Eventually, the optimized PCL/CN and PCL/CN/MO specimens were evaluated by FTIR, DSC, Tensile, water contact angle, antibacterial assays, cell viability, and drug release analysis for determining their function and properties.

Magnetite nanoparticles (MNPs) were synthesized on the surface of halloysite nanotubes (HNTs) through co-precipitation approach and the achieved nanocomposites were employed as the support of surface polymerization of [2-(acryloyloxy)ethyl]trimethylammonium chloride (AETAC) to obtain a hybrid adsorbent for removal of Sunset Yellow from wastewater. The resulting magnetic nanocomposite was assessed by several characterizations. The X-ray diffraction (XRD) pattern confirmed the synthesis of Fe3O4 MNPs on HNTs. The field emission scanning electron microscope (FESEM) images showed that spherical Fe3O4 MNPs were successfully synthesized and the energy-dispersive X-ray spectroscopy (EDS) confirmed the presence of Fe element in nanocomposite structure. The solid adsorbent was prepared by the aid of the magnetic HNTs as the support. The vibrating sample magnetometer (VSM) was employed for assessment of the magnetic properties of the magnetic HNTs and the solid polymeric adsorbent. The Freundlich isotherm model was fitted the experimented data better than Langmuir isotherm model, indicating the multi-layer adsorption of the dye to the polymeric adsorbent. The polymeric adsorbent had facile elution procedure by the aid of NaCl solution of 1 M. The prepared adsorbent showed fast separation kinetic, reaching equilibrium in about 15 min. and high absorption capacity of 33.8 µmol/g at room temperature, which made this adsorbent a good candidate for industrial wastewater treatment procedures.

This study aimed to investigate the effect of modification of halloysite nanotubes (HNTs) with iron oxide on the morphology and thermomechanical properties of polyurethane with shape memory behavior. Iron oxide-functionalized halloysite nanotubes (I-HNTs) were synthesized via co-precipitation method. Polyurethane nanocomposites containing 1 and 2 wt. % HNTs and I-HNTs were prepared in situ by prepolymer method. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) confirmed the successful synthesis of I-HNT. Dynamic mechanical thermal analysis (DMTA), FTIR equipped with reduced overall reflectance, atomic force microscope (AFM), and differential scanning calorimetry (DSC) showed that phase separation increased by the addition of HNTs or I-HNTs and their propensity to rigid sections. The maximum degree of micro-phase separation was 66.8% in the sample containing 2 wt. % I-HNT. In DMTA, an improvement in the shape's return speed in the shape memory behavior was observed by adding HNTs to neat polyurethane. This increase was significant in samples based on I-HNT and the highest recovery rate was 179.1 GPa.°C−1 in the sample containing 2 wt. % I-HNT. Examination of shape memory behavior showed that by adding 1 wt. % HNT, shape fixity parameter increased due to the increase in soft phase purity and shape recovery parameter decreased due to reduced mobility in the presence of HNTs. This effect was more significant in I-HNT-based samples, and the highest shape stability (96.7%) was observed in nanocomposites containing 2 wt. % I-HNT.

Surface hydrophilicity and scaffold integrity determine the drug release behavior of drug loaded electrospun fibrous mats. When mixture miscibility is acceptable, blend electrospinning of hydrophobic with hydrophilic polymers can improve scaffold hydrophilicity while the hydrophobic polymer maintains the mechanical strength of scaffold. Polycaprolactone (PCL) and Pluronic P123 (P123) blend electrospinning has been investigated. In routine blend electrospinning, surface enrichment of Pluronic sets a limit for P123 weight ratio in which exceeding from that limit causes the excess P123 to be accumulated within the electrospun fiber core. To overcome this setback, a method named surfactant assisted water exposed (SAWE) electrospinning was introduced which was proven to be effective for increasing the surface enrichment of Pluronic. In order to test the validity of this method, the electrospinning of solution containing PCL which is exposed to aqueous solution of P123 was investigated. This new method was named surfactant aqueous solution exposed (SASE) electrospinning. Myelin formation at the contact interface of aqueous solution and chloroform solution was studied and it was found that this layer can effectively barricade the migration of Pluronic chains between immiscible phases. For SASE, fiber surface coverage by P123 was uneven and loose. Electrospun scaffolds from SAWE and SASE were loaded with drug to investigate the effect of the exposure time during electrospinning on in vitro drug release. By increasing the exposure time, the abnormal two-stage phased release profile of SAWE became normal with moderate initial burst. Longer exposure time increased the initial burst of the drug loaded SASE fibers. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 597-609, 2019.

Dual stimuli-responsive yolk-shell nanoparticles with cross-linked poly(acrylic acid) (PAA) pH-responsive core and cross-linked poly(2-hydroxyethyl methacrylate) (PHEMA) temperature-responsive shell were synthesized via two different methods In the first method, silica encapsulated PAA (PAA@SiO2) was used as seed in distillation precipitation polymerization (DPP) of HEMA to yield PAA@SiO2@PHEMA from which silica layer was etched by HF solution to produce yolk-shell PAA@air@PHEMA nanoparticles. In the second method, swollen PAA nanoparticles at pH = 10 were used as seeds in emulsion polymerization of HEMA to yield core-shell PAA@PHEMA nanoparticles. After dispersion of PAA@PHEMA nanoparticles in acidic medium at pH = 2, yolk-shell nanoparticles were formed through deswelling of pH-responsive cores due to protonation of carboxyl groups. Synthesized nanoparticles were characterized using FT-IR, FE-SEM and TEM methods to observe yolk-shell nanostructure for both synthesis routes. Stimuli-responsive behavior of the nanoparticles was investigated by UV-vis spectrometer where similar behaviors were obtained for template-assisted and template-free synthesized yolk-shell nanoparticles. Finally, both yolk-shell nanoparticles were examined as potential carriers for controlled release of doxorubicin hydrochloride (DOX) anti-cancer drug.

Modified halloysite nanotubes (HNT-NH2 and HNT-COOH) were synthesized by a coupling reaction with 3-aminopropyltriethoxysilane and maleic anhydride from hydroxyl groups of neat halloysite nanotubes (HNTs). Successful attachment of functional groups onto HNTs was evaluated by Fourier transform infrared and thermogravimetric analysis. X ray diffraction was used to study the crystalline structure of scaffolds and the formation of intercalated structure as a result of improved dispersion and decreased agglomeration of modified nanoparticles. Neat HNT, HNT-NH2 , and HNT-COOH were subsequently introduced into polycaprolactone/Pluronic P123 (PCL/P123) electrospun substrate. Morphology, thermodynamics, mechanics, and biocompatibility of resulted electrospun nanocomposites were evaluated. Nanofibers containing modified HNTs showed excellent mechanical performance and thermal stability in comparison with those containing neat HNTs. homogeneous dispersion of the modified HNTs and strong interfacial adhesion between nanotubes and polymer matrix can be considered for mentioned improvements. Ultraviolet-visible spectrophotometer was used to study diphenhydramine hydrochloride and diclofenac sodium release from nanocomposites containing drug loaded modified and neat HNTs. Nanocomposites containing drug loaded HNT-COOH exhibited prolonged release of drug molecules in comparison with that of neat HNTs. MTT assay reveled that PCL/P123/modified HNTs nanocomposites provide a suitable platform for cell growth where PCL/P123/HNT-NH2 can facilitate cell attachment through electrostatic interactions between negatively charged phospholipids bilayer membrane of cells and positively charged HNT-NH2 embedded in PCL/P123 substrate. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1276-1287, 2018.

Adenosine triphosphates (ATP) are excellent energy-carrying molecules due to their phosphate functional groups that link through phosphodiester bonds, while halloysite nanotubes (HNTs) are layered mineral materials which exist naturally and have a large number of active sites for energy storage reinforcement. The use of HNTs and ATP in combination will provide a new approach to producing advance electrode materials for energy storage devices. Herein, a simple and cost-effective chemical method is introduced to fabricate a composite electrode of functionalized halloysite nanotubes (FHA) loaded with a pyridinium-based ionic liquid (PyPS) and conductive polymer, poly ortho amino phenol (FHA-PyPS-POAP) for use in supercapacitor. The prepared FHA-PyPS-POAP electrode exhibited outstanding electrochemical behavior with a capacitance being up to 626 F g−1 at 1 A g−1 in a 1 M Na2SO4 electrolyte while preserving remarkable rate capability and indicating superior cycle stability. Besides, the FHA-PyPS-POAP electrodes employed in the two-electrode system with a capacitance of 306 F g−1 at 0.5 A g−1 and possessed an energy density of 20.8 W h kg−1 at 350 W kg−1. Also, the symmetrical supercapacitor shows capacitance retention remaining 93.9% for FHA-PyPS-POAP//FHA-PyPS-POAP at 8 A g−1 over 5000 cycles. Thus, these promising findings demonstrated a high potential as a significant application in developing energy storage devices with enhanced energy and power concentrations.

Curcumin has been proven to be an effective herbal derived anti-inflammatory and antioxidant biocompatible agent. In this research, poly(lactic-co-glycolic acid) (PLGA) (as a biocompatible and generally recognized as safe (GRAS) polymer) nanoparticles containing Curcumin were electrosprayed from different polymeric solutions with different concentrations for the first time. Morphology of these nanoparticles in the absence/presence of Curcumin was evaluated by scanning electron microscope, transmission electron microscope, and X-ray photoelectron spectroscopy analyses. Perfectly shaped nanoparticles with an average size of 300 and 320 nm were observed for neat and Curcumin-loaded PLGA, respectively. Curcumin-loaded electrosprayed nanoparticles showed a normal moderate initial burst and then a prolonged release period. Weibull, Peppas, and modified Korsmeyer-Peppas models were applied to study the kinetic and mechanism of Curcumin release from PLGA nanoparticles. Results showed high specific surface area and spherical geometry of the nanoparticles. Effectiveness of the electrospray method as a promising technique for preparing Curcumin-loaded nanoparticles was confirmed in this study. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 285-292, 2018.

In order to improve surface hydrophilicity, blood compatibility and cell-antiadhesion of polypropylene (PP) film, polypropylene oxide (PPO)-polyethylene oxide-PPO used as macromolecular surface modifier through physical blending. Surface properties of blended PP/Pluronic F127 (PF127) samples were investigated by attenuated total reflection infrared spectroscopy and water contact angle measurements. Results demonstrated that PF127 migrated to the surface. Thus, mechanical properties of blended PP/PF127 samples with the aim of the revealing the effects of the presence of modifier in the bulk were investigated through differential scanning calorimetry, X-ray diffraction, and tensile tests. The biocompatibility and hemocompatibility of modified PP films were evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, platelet-rich plasma, and hemolysis tests. These results showed excellent anticell and antiplatelet adhesion which deems the prepared blended films proper biomaterials. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 652-662, 2018.

Free and cellulose nanocrystals (CNCs)-grafted block copolymers of acrylic acid and N-isopropylacrylamide with various poly(N-isopropylacrylamide) (PNIPAAm) block lengths as dual temperature- and pH-sensitive materials were synthesized by reversible addition-fragmentation chain transfer polymerization via an R-approach method. Controlling lower critical solution temperature (LCST) of the products by changing the PNIPAAm block length, addition of CNC, and variation of pH was studied. The free and CNC-grafted block copolymers were analyzed by Fourier transform infrared and proton nuclear magnetic resonance. LCST of copolymers was measured by dynamic light scattering using their hydrodynamic diameters. The block copolymers reversibly form core-corona structure with PNIPAAm as core and poly(acrylic acid) (PAA) as shell above LCST at higher pH values. LCST point shifts to higher temperatures by increasing pH and CNC content and also lowering PNIPAAm block length. By decreasing pH below 4 at certainly low temperatures, PAA becomes core and PNIPAAm forms corona. Thermal behavior of the CNC-grafted polymers was studied by thermal gravimetric analysis and differential scanning calorimetry. Morphology of the polymer-grafted CNC was examined by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 231-243, 2018.

N,N'-methylenebis(acrylamide) (MBA)-crosslinked poly(acrylic acid) (PAA) particles with low degree of cross-linking were synthesized using distillation precipitation polymerization. Size and size distribution of particles were obtained using dynamic light scattering and field emission scanning electron microscopy( and results showed that microspheres had a narrow size dispersity. Proton nuclear magnetic resonance results indicated that amount of cross-linker in structure of particles is a little more than the molar percentage of feeded MBA because of greater activity ratio of MBA than AA. pH-responsive behavior of samples was investigated using UV-vis. absorption at 480 nm where each sample showed a sudden deplete in UV absorbance at a peculiar pH. Synthesized particles were used as carriers of anti-cancer drug doxorubicin using two different approaches including physically loading of drug and drug conjugation via an acid-labile hydrazone linkage. Release results showed that in the first case, amount of released drug has an inverse relationship with the amount of cross-linker in the structure and also, by adding an acid-labile linkage, the amount of burst release decreased drastically. Also, the amount of released drug for conjugated systems was much lesser than particles with physically loaded drug. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 342-348, 2018.

Fluorination of graphene nanomaterials has multitude merits owing to the peculiar temperament of the carbon-fluorine (C-F) bond. However, the current synthesis modalities of fluorinated graphene (FG) are based on the usage of toxic materials at high temperatures, which are problematic to be used. The methods to overcome these problems are challenging for chemists. Ionic liquids (ILs) have been used in several chemical processes as auxiliaries and eco-friendly alternatives instead of volatile organic solvents because of their properties. Consequently, herein we exploited a highly effective and green process for the synthesis of FG at mild temperature (80 °C) by using ammonium fluoride salt as fluorine agent and a synthesized acidic IL ([TEA]+[TFA]–) as a solvent. Our goal was to synthesize enriched FG with a high degree of fluorination (66.4 wt.% of F) and F/C ratio (2.2), which measured and confirmed by XPS analysis. Subsequently, the obtained FG was used as a nanocarrier for delivery of curcumin to cancerous cells. The in-vitro results showed that these nanosheets possessed a higher Cur-loading efficiency (78.43%) than commercial FG (52.12%) due to the sheet-like structure with folded edges. This, in turn, translated into an excellent in-vitro anti-cancer effect when tested against cancerous cells.

Potential complications during fixed orthodontic procedures are white spot lesions (WSLs) and tooth decay. This study evaluated the anti-biofilm activity of an orthodontic adhesive (OA) incorporating curcumin (Cur) doped Poly lactic-co-glycolic acid nanoparticles (Cur-PLGA-NPs), which can have the highest concentration of Cur-PLGA-NPs and shear bond strength (SBS) value simultaneously, against cariogenic bacteria i.e., Streptococcus mutans.Following synthesis and confirmation of Cur-PLGA-NPs, SBS and adhesive remnant index (ARI) of the modified orthodontic adhesives (MOA) containing Cur-PLGA-NPs (3, 5, 7, and 10 % wt.) were measured using universal testing machine and stereomicroscope, respectively. After artificial aging (continuously rinsed up to 180 days), the residual anti-biofilm ability of MOA which can have the highest concentration of Cur-PLGA-NPs and SBS value simultaneously were determined by anti-biofilm assay following photoexcited enamel slab bonded brackets by MOA containing Cur-PLGA-NPs against S. mutans biofilms using crystal violet assay.Adhesive with 7 % wt. Cur-PLGA-NPs revealed the highest concentration of Cur-PLGA-NPs and SBS value (16.19 ± 2.69 MPa, P0.05) simultaneously. No statistically significant difference in ARI scores was observed between the MOA and control (Transbond XT without the Cur-PLGA-NPs). On days 15, 30, 60, 90 and 120 there was a considerable decrease in optical density (OD) of preformed S. mutans biofilms on photoexcited enamel slab bonded brackets using MOA containing 7 % wt. Cur-PLGA-NPs, to 94.1 %, 79.6 %, 69.6 %, 69.4 %, and, 55.1 % respectively in comparison to the control group (all, P0.05). From days 150 onwards, microbial biofilm formation was progressively increased on enamel slab bonded brackets using MOA containing 7 % wt. Cur-PLGA-NPs compared to the control group (OA). Although chlorhexidine (2 %; as positive control) showed significant activity against pre-formed S. mutans biofilms on enamel slab bonded brackets using OA (99.1 % biofilm reduction; P = 0.001), its activity was slightly higher but not significant than photoexcited enamel slab bonded brackets using MOA containing 7 % wt. Cur-PLGA-NPs on the days 15 and 30 (both, P0.05).The 7 % wt. Cur-PLGA-NPs can serve as an orthodontic adhesive antimicrobial additive as exposure to blue laser provides an acceptable antimicrobial effect against cariogenic bacteria for a considerable time.

A novel water-compatible magnetic molecularly imprinted polymer (MMIP) was fabricated for sunset yellow dye removal by surface imprinting approach. The magnetic halloysite nanotubes were prepared by co-precipitation method and used as support for surface polymerization. The synthesis of Fe3O4 nanoparticles on the halloysite nanotubes were confirmed by X-Ray Diffraction (XRD) and energy dispersive spectroscopy (EDS). Water and ethanol were used as polymerization solvents and the effect of porogenic solvent was investigated on final adsorption behavior of the polymers. The Brunauer-Emmett-Taller (BET) and Barrett-Joyner-Halenda (BJH) techniques were employed for surface area and pore diameter assessments. The MMIP synthesized in water (W-MMIP) showed higher adsorption capacity (46.4 μmol/g) and selectivity (Ksel = 3.60) toward sunset yellow dye. The adsorption kinetic data were well-fitted by pseudo-second-order kinetic model representing the chemisorption of dye molecules onto the specific recognition sites of MMIPs. The intraparticle diffusion was assessed by Morris-Weber kinetic plots. The experimental data were assessed by the Langmuir and Freundlich adsorption Isotherm models.

Copolymer brushes composed of N,N-dimethylaminoethyl methacrylate (DMAEMA) and 2-hydroxyethyl methacrylate (HEMA) were tethered on the surface of HNTs (HNTs) through surface-initiated atom transfer radical polymerization (SI-ATRP). ATRP initiator was anchored to surface and copolymers were synthesized from surface with different compositions of monomers. Successful grafting of copolymer brushes was approved by FTIR, TGA, XPS, FE-SEM, TEM, and N2 adsorption-desorption.1H NMR was used to determine the composition of copolymers. pH-sensitive properties of copolymer-grafted nanotubes were investigated by UV-visible absorbance in different pH values. Finally, loading and in vitro drug release from neat and copolymer-grafted HNTs were investigated using diphenhydramine hydrochloride as a model drug. Incorporation of DMAEMA to structure of polymers led to pH sensitivity of grafted-copolymers and controlled release of drug upon varying the pH of release medium. pH-dependent drug release showed that drug r...

To overcome the problems related to the low surface enrichment of blended fibers from hydrophilic polymer, routine blend electrospinning setup was modified by exposing the polycaprolactone (PCL)–Pluronic P123 solution to water in order to attract the hydrophilic chains toward the fiber surface. Analysis of the modified fibers revealed a drastic surge of hydrophilic polymer surface enrichment value in comparison with that of the routine method which suggested homogenously positioned Pluronic on the surface and the subsequent reduction of its accumulations within fibers. The thermogram of the proposed method showed induced crystallization in the Pluronic section. Furthermore, the intensity of PCL characteristic peaks decreased for this method.

Global energy demand and the seriousness in sustainable energy obligations along with a large amount of CO2 emission and rapid depletion of fossil fuels have diligently persuaded the researchers to promote eco-benign energy storage systems with high performance. High energy and power density, long cycling life, ultra-flexibility, environment friendly, light-weight with challenges of the benefits of industrial applications, safety, and reliability are currently considered in inventing efficient energy storage systems. Therefore, promoting and employing effective technologies to storing energy has widely become a development trend. Achieving that object is paved by developing batteries and supercapacitors (SCs) which are remarkably attracted enormous research interest and scientific reports. Supercapacitors are on a rapid and significant development path, with possessing desirable electrochemical benefits, including high power density, long cycle-life, rapid charge–discharge rate, and absolutely demanded commercial features. To understand the real performance of investigated supercapacitors, we considered the electrochemical output of applied SC systems. Actually, various types of electrode materials, electrolytes, have been significantly used to improve the electrochemical features in terms of specific capacitance, energy density, power density, and cycle life. Here, we focused on reviewing filed patents on application of MOFs in SCs and the recent improvements in employed components consisting of electrode and electrolyte in supercapacitive behavior. From the technical results, ZIF-series, UiO-66/67, MIL-based, MOF-74, MOF-5, Ni3(HITP)2, Cu3(HITP)2 are widely used in MOF-based SCs. Patents are costly to register and they are also extremely reliable documents that are remarkably reliable in comparison to articles. Because patents are seriously challenged scientifically and legally, they contain critical information that inventors must disclose in full detail. Compared to articles, patents are a truly reliable reference for all researchers, especially youthful researchers, start-ups, and technology developers, due to their complete disclosure, reproducibility and 100% reliability. While innovation is a key component in both papers and patents, patents certainly contain an Inventive Step (IS), which is the main criterion that distinguishes these two references. Furthermore, mixed-metal MOF and compositing materials such as PANI (conductive polymers), graphene, CNTs, and nanomaterials or using as precursor material, provide higher surface area, simultaneous EDLC and pseudocapacitance effect which is desirable for electrochemical devices. Among considered files, only 135 patents were closely related to this subject showing its stepping-stone age. In addition, the aqueous electrolyte such as KOH and H2SO4 are well-demanded to ease charge transfer in SCs. The statistical analysis showed that China is leading developer towards developing MOF-based SCs; while, the USA and South Korea are two next following countries. China seems to have a very large market share for this type of SC. The USA, EU, and South Korea, despite their close economic share and market share, need to sacrifice more diligent efforts in competition with China. We believe that this review opens a new prospective of MOF-based SCs for future electrochemical considering to provide higher performed devices.

The structure of electrode materials is still a critical challenge to improve the electrochemical features toward widespread application of supercapacitors. Functionalized graphene oxide and their derivatives or composites can synergically increase the electrochemical performance. In this work we synthesized graphene oxide (GO) through Hummer's method and then GO was functionalized by L-histidine-methyl ester dihydrochloride (L-HMEC) in the presence of an ionic liquid (1-buthyl-3-methyl-imidazolium bromide). The obtained product was further reacted with triethyl amine (Et3N) and CrCl3 to host a Cr-containing molecule grafted covalently on the GO surface (Cr-GO). The fractal concept showed a porous structure based on log-log scale plotting of potential at current density. Additionally, the Cr-GO composited electro-synthetically with poly ortho amino phenol (POAP) as a conductive polymer, and then employed as an efficient porous electrode material in a two-electrode setting (Cr-GO-POAP). The employed Cr-GO-POAP improved the supercapacitive behavior with enhancing conductivity and facilitating electron movements in electrolyte with specific capacitance of 354 F g−1 at 0.5 A g−1 and obvious wider CV curves. Cyclic voltammetry and EIS techniques showed high-efficient performance in electron conducting with excellent durability and cycle life (~94%) after 5000 cycles. Both energy and power densities were improved by 12.29 W h kg−1 and 250 W kg−1, respectively.