Search

An exceptionally productive and sustainable procedure is described in this paper to fabricate 1-(benzothiazolylamino) methyl-2-naphthols using a novel green nanocomposite of chitosan and diethylenetriamine-modified graphene oxide, supported methanesulfonic acid (Ch@GO-DETA.MSA.). For the synthesis of the nanocomposite, maleic anhydride was first attached to chitosan, and then, graphene oxide was modified by diethylenetriamine (GO@DETA). Subsequently, nanocomposite was prepared from the reaction of chitosan-g-maleic anhydride and GO@DETA. Finally, methane sulfonic acid was added to the nanocomposite to afford Ch@GO-DETA.MSA. Structural properties of the nanocomposite were explored through various techniques including X-ray diffraction (XRD), thermal gravimetric analysis (TGA), FTIR spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). 1-(Benzothiazolylamino) methyl-2-naphthols were efficiently prepared in high to excellent yields through a multicomponent reaction of 2-aminobenzothiazole, aryl aldehydes, and 2-naphthol using Ch@GO-DETA.MSA. nanocomposite under solvent-free conditions. The proposed protocol exhibited superiority over several published protocols due to its nontoxicity and eco-friendly, catalytic ability, short reaction times, generality, efficiency, solvent-free condition, and simple workup.

To promote the low photocatalytic efficiency caused by the recombination of electron/hole pairs and widen the photo-response wavelength window, ZnFe2O4@ZnO-N/B/RGO and ZnFe2O4@ZnO-C3N4 ternary heterojunction nanophotocatalysts were designed and successfully prepared through a sol–gel technique. In comparison to bare ZnFe2O4 and ZnO, the ZnFe2O4-ZnO@N/B/RGO and ZnFe2O4@ZnO-C3N4 ternary products showed highly improved photocatalytic properties in the degradation of methyl orange (MO) under ultra-violet (UV) and visible light irradiation. Various physicochemical properties of the photocatalysts were evaluated through field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), UV–visible diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM) techniques. The observations indicated that the ternary heterojuncted ZnFe2O4@ZnO-N/B/RGO absorbs lower energy visible light wavelengths, which is an enhancement in the photocatalytic properties of ZnFe2O4@ZnO loaded on reduced graphene oxide (RGO) nanosheets and graphite-like carbon nitride (g-C3N4). This gives the catalyst photo-Fenton degradation properties.

In this study, a nanogel-hydrogel hybrid was synthesized to improve drug delivery system performance. First, poly (acrylic acid-N-isopropylacrylamide) nanoparticles were synthesized using acrylic acid, N-isopropylacrylamide, sodium dodecyl sulfate, and MBA in the presence of APS as a radical initiator. Then the synthesized (A-N) nanogel was added to a solution of chitosan in acetic acid and (A-N) nanogel/ CTS-A hydrogel was synthesized in the presence of AA, MBA and ASP. (A-N) nanogel/ CTS-A hydrogel was characterized by IR, SEM, EDX, TEM, DLS, TGA, DTG and BET techniques. Doxorubicin (DOX) solution was used to evaluate drug loading capacity and the amount of drug-loaded was calculated using UV analysis. Drug release behavior was investigated by placing DOX-loaded (A-N) nanogel/ CTS-A at different temperature and pH ranges. Our research indicated the drug release for both carriers was controlled by diffusion mechanism but, increasing of temperature had not influenced the drug release mechanism. However, this study suggests that by trapping nanoparticles in a hydrogel system, drug carriers with higher absorption capacity and slower kinetic release can be created.

In this paper, a novel iron oxide nanocomposite hydrogel was prepared by simultaneous formation of superparamagnetic iron oxide nanoparticles and cross-linking of poly(acrylic acid) grafted onto sodium alginate polysaccharide. The prepared optimized hydrogel was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy with energy-dispersive X-ray analysis, atomic force microscopy, and transmission electron microscopy. Moreover, swelling capacity of the obtained hydrogel was measured at different temperatures, different pHs, absorption under load, and magnetic field to assess the sensitivity of ION–PAA-g-NaAlg hydrogel. This hydrogel was also examined as a controlled drug delivery system. Doxorubicin and tetracycline (as model drugs) release was investigated at different pHs, different temperatures, and magnetic field. The release curves were nicely fitted by the Korsmeyer–Peppas equation, and the release is controlled by polymer relaxation process.

The addition of magnetic nanoparticles gives unique properties to hydrogels. Magnetic-sensitive gels have various applications in targeted drug delivery, separation, and sensing. One of the most advantageous aspects of using magnetic nanoparticles is their ability to respond to remote control by an external magnetic field. Microgels loaded with magnetic nanoparticles enhance control in magnetic resonance imaging. In addition, these materials change the rate of hydrogel swelling in the magnetic field. In this study, we report a novel type of magnetite nanocomposite based on poly (acrylamide-co-acrylic acid) hydrogel by simple, cost effective, and eco-friendly process in a viscous medium containing glycerol at room temperature. For this purpose, first, Fe3O4 nanoparticles were synthesized through sedimentation process. The final nanocomposite was efficiently obtained in a short reaction time under ultrasonic irradiation at room temperature and the absence of chemical initiator. The SEM images show a uniform distribution of Fe3O4 nanoparticles in the hydrogel matrix with a morphology similar to cubic crystalline lattices. The swelling behavior of the prepared magnetite nanocomposites were investigated in three different mediums and showed a fast initial swelling followed by a mild increase until attaining equilibrium. The highest and the lowest swelling was obtained in pure water and under pressure, respectively. Also, the absorption and release of two drugs, fluvoxamine and ciprofloxacin, were studied in a phosphate buffer solution at 37 °C to investigate the efficiency of entitled sonochemical prepared hydrogel nanocomposite in drug delivery field.

In this study, at first, gold nanorods (GNRs) were synthesized and then they were coated with a layer of hydrogel composed of poly(N-isopropylacrylamide) (PNIPAM) grafted onto carboxymethyl cellulose (CMC) as a backbone. The chemical structure of GNRs/PNIPAM-g-CMC hydrogel was characterized by Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), atomic-force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The swelling properties of the obtained GNRs/PNIPAM-g-CMC hydrogel were studied at different times and temperatures. In addition, drug release from doxorubicin-loaded GNRs/PNIPAM-g-CMC hydrogel was examined at different temperatures during time. The drug release mechanism was studied by first-order, second-order, and Ritger–Peppas models. Finally, the GNRs/PNIPAM-g-CMC hydrogel biocompatibility was tested against L929 mouse fibroblast cells by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) method. Our study suggests that GNRs coated with low-cost hydrogels can be excellent candidate for drug delivery systems.

Hydrogels, nanogels, and nanocomposites show increasing potential for application in drug delivery systems due to their good chemical and physical properties. Therefore, we were encouraged to combine them to produce a new compound with unique properties for drug release systems. To this aim, we first prepared poly [(N-isopropylacrylamide)-co-(2-dimethylamino ethyl methacrylate) nanogel by copolymerization processes and then added it into the solution of poly (2-dimethylamino ethyl methacrylate)] grafted onto salep. Through dropwise addition of mixed aqueous solution of iron salts into the prepared polymeric solution, a novel hydrogel nanocomposite with excellent pH, thermo, and magnetic responsive was fabricated. The obtained hydrogel nanocomposite were characterized by Fourier transform infrared spectroscopy, thermo gravimetric analysis, X-ray diffraction, scanning electron microscopy, vibrating sample magnetometer, and atomic force micrographs. The dependence of swelling properties of hydrogel nanocomposite on the temperature, pH, and magnetic field were investigated. The release behavior of doxorubicin hydrochloride (DOX) drug from DOX loaded into synthesized hydrogel nanocomposite was investigated at different pHs, temperatures, and magnetic field. In addition, the drug release behavior from obtained hydrogel nanocomposite was monitored via different kinetic models. Lastly, the toxicity of the DOX and DOX-loaded hydrogel nanocomposite were studied on MCF-7 cells at different times. These results suggested that the obtained hydrogel nanocomposite might have high potential applications in drug delivery systems.

In this study, a facile method was introduced for preparation of a ligand-coated CdTe QDs (CdTe-L QDs) for applying as a new optical nano-sensor in determination of Cr3+ ions in aqueous solutions. The prepared CdTe-L QDs were characterized using different analytical techniques including transmission electron microscopy (TEM), UV-Vis, thermogravimetric (TG) analysis, Fourier-transform infrared (FTIR), and fluorescence spectroscopies. It was found that the fluorescence intensity of the CdTe-L QDs at 540 nm (excitation at 380 nm) was selectively quenched in the presence of trace amounts of Cr3+ ions in comparison to different metal ions. In other word, a simple, highly sensitive, selective, and rapid analytical approach was used for the determination of Cr3+ ions in the concentration range of 6.78 ± 0.05 × 10−8–3.70 ± 0.02 × 10−6 mol L−1 with a detection limit of 20.30 ± 0.03 × 10−9 mol L−1. Furthermore, the designed nano-sensor was well used for the quantification of Cr3+ ions in real samples with satisfactory analytical results, and the results were compared with the standard methods (inductively coupled plasma emission spectroscopy (ICP-OES)).

A novel thermo/pH/magnetic-triple-responsive nanogel was synthesized by grafting N-isopropylacrylamide and acrylic acid onto sodium alginate to modify magnetic graphene oxide as a drug delivery system. The synthesized nanogel was characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), vibrating sample magnetometer (VSM), atomic force micrographs (AFM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The obtained nanogel displayed excellent reversible transmittance changes in response to pH, temperature, and magnetic field. The performance of the nanogels to load doxorubicin (DOX) drug and to sustain doxorubicin release was tested upon exposure to pH, temperature, and magnetic field variations. The mechanism of drug release was proposed in this paper by different kinetic models. In addition, the effects of nanogels and DOX-loaded nanogels on MCF-7 cells were examined and results were compared with free DOX drug. The in vitro results demonstrated that this triple-responsive nanogel can be an appropriate candidate for applications in cancer therapy.

Nanogels have been demonstrated to be desirable for hydrophilic anticancer drug delivery. This study presents a novel nanogel consisting of sodium alginate-modified graphene oxide (SA-GO) and N-isopropylacrylamide (NIPAM) for sustained delivery of doxorubicin (DOX) drug. The PNIPAM/SA-GO nanogel was studied by various techniques including scanning electron microscopy, atomic force microscopy, dynamic light scattering, Fourier transform infrared spectroscopy, and thermo-gravimetric analysis. Subsequently, the thermo-responsive behavior of the PNIPAM/SA-GO nanogel was investigated by UV–Vis spectroscopy. DOX was successfully loaded into the PNIPAM/SA-GO nanogel in order to study entrapment efficiency and drug release behavior. Moreover, biocompatibility of the DOX-loaded PNIPAM/SA-GO nanogel was examined against Hella cells and was compared with free PNIPAM/SA-GO nanogel and DOX. This work offers that the nanogels could be developed further as an effective bioactive molecule delivery system.

In this study microwave irradiation was used to synthesis the silver nanocomposite hydrogel and the usefulness as an adsorbent for the preconcentration, extraction and determination of methyl red (MR) from water by dispersive solid phase extraction method was evaluated. For this purpose, silver nanocomposite hydrogel (SNH) was synthesized and characterized by thermo-gravimetric (TG) analysis, FT-IR, TEM and SEM images. The effects of some important variables such as centrifuge time (min), the pH of the methyl red solution, amount of adsorbent (g), acetone volume (mL) and chloroform volume (mL) on methyl red removal were studied using central composite design (CCD) and the optimum experimental conditions were evaluated by the desirability function (DF) combined response surface methodology (RSM). Under the optimal experimental conditions, the detection limit was found to be 1.4 μg mL− 1 for MR adsorption. The limit of quantification and the linear range of calibration curve were 4.6 μg mL− 1 and 0.1–25 μg mL− 1, respectively.

Nanogels (NGs) are three-dimensional water soluble cross-linked hydrogel materials in the nanoscale size range with a high loading capacity for guest molecules and act as drug carrier systems. In the present work, a new type of thermo/pH sensitive NG comprising salep modified graphene oxide (SMGO) with branched N-isopropylacrylamide (NIPAM) and acrylic acid (AA) was prepared. The SMGO/P(NIPAM-co-AA) NGs exhibited nanoporous structure and spherical particles with diameters about 82nm as characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The samples were also characterized by Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TGA) to further confirm about the formation of NGs. Doxorubicin (DOX) loaded SMGO/P(NIPAM-co-AA) NGs showed thermo/pH dependent releasing behavior: slow drug release at neutral pH and lower temperature but increased significantly in acidic pH and higher temperature, without any burst release. In addition, the NGs exhibited no effect on the cell viability in the tested concentration range up to 410μg/mL and drug release systems enhanced toxicity to HeLa cells when compared to the equivalent dose of the free drug. Overall, our results put forth NGs as potential candidates in the development of a new nanocarrier for anti-cancer drug delivery.

Current discovery of different modifications of multi walled carbon nanotubes has motivated research for their potential applications in various field such as adsorbent materials, and drug delivery. Many different modified carbon nanotubes have been achieved, including combinations with iron oxide nanoparticles (NPs) for their unique properties including magnetic properties, nontoxicity, biocompatibility and capability which have considerable impact on the delivery of the drug at the targeted area. However, one of the disadvantages of this nanocomposite in biological fluids is that iron oxide NPs might be quickly cleared by the bloodstream before realization of their targets. In order to overcome this obstacle, polymers could be used as stabilizer to achieve a highly stable NPs@MWCNT composite. As a result, a magnetic multi walled carbon nanotube hydrogel nanocomposite based on poly (acrylic acid) grafted onto salep was synthesized and then fully characterized by using FTIR spectroscopy, thermogravimetric analysis, EDAX spectrum, SEM, TEM, AFM images, and vibrating sample magnetometer (VSM) and synthesis mechanism was suggested. Besides, swelling kinetics and loading and releasing of tetracycline hydrochloride as a model drug in various conditions were also investigated.

Measurement of biologically active compounds in living systems by highly sensitive methods seems to be attractive nowadays. So, design of fluorescence-based quantum dots nanosensors to detect low concentrations of pharmaceutical compounds is a highly attractive area of research. However, reaching the higher fluorescence intensity of quantum dots and reducing the low toxicity of quantum dots by ligand (polymer) exchange method are two more important items. Here, the preparation of novel fluorescence nanosensors κC-CdTe/ZnS quantum dots is reported. After structure confirmation by different analysis methods such as FTIR, TGA, and TEM, fluorescence intensity response of κC-CdTe/ZnS QDs with Epirubicin drug investigated. Based on obtained results, not only this nanosensor developed but also the fluorescence quenching was explained by the typical Stern–Volmer equation. The best linear quenching equation for entitled nanosesor in the presence of Epirubicin is F0/F = 0.0379Q + 1.15 (R2 = 0.99). Moreover, the detection limit of Epirubicin was found around 0.05 × 10−6 mol/L at 25 °C. All of the results showed that this method could be a reliable and suitable approach for the determination of Epirubicin in commercial tablets.

The purpose of this study was to develop a novel dual thermo- and pH-responsive silver nanocomposite hydrogel (SNH) for drug release applications. This smart SNH was prepared in a facile one-pot method by in situ reduction of silver ions in salep solution and then grafting of poly(vinylpyrrolidone-co-acrylic acid) onto it. The SNH was characterized by transmission electron microscopy (TEM), scanning electron microscopy with energy-dispersive X-ray analysis (SEM–EDAX), thermo-gravimetric analysis (TGA), Fourier transform infrared (FT-IR), UV–Vis spectroscopy, and cyclic voltammetry. The dependence of swelling properties of the prepared SNH on the reaction variables (such as monomer, Ag NO3, and cross-linker concentrations), temperature, pH, and salt was investigated. The potential of obtained SNH was examined for the deferasirox release from prepared hydrogel under different temperatures and pHs. The evaluation of release mechanism and determination of diffusion coefficients were also studied. In addition, SNH showed good antibacterial potentials. The results of this study provide valuable information regarding the development of dual stimuli-sensitive SNH for biomedical applications.

Silver nanocomposite hydrogel (SNH) based on poly(acrylic acid) grafted onto salep was prepared without initiator and under just 2 min ultrasonic irradiation for the first time. The SNH was then applied as an adsorbent for Rhodamine removal from aqueous solution. The SNH adsorbent was characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy images and X-ray photoelectron spectroscopy. A 24 full factorial central composite design, a linear mathematical model representing the influence of different variables and their interactions, was successfully employed for experimental design and analysis of the results. Analysis of variance demonstrated that Rhodamine adsorption significantly increased with increases in the amount of adsorbent, extraction time, stirring rate of the solution and Rhodamine volume as donor phase volume, but slightly decreased with an increase in temperature and pH of Rhodamine solution. The adsorption behaviors showed that the adsorption kinetics were in good agreement with a pseudo-second-order model for Rhodamine removal from aqueous solution. Thermodynamic studies revealed the feasibility and exothermic nature of the system. Adsorption mechanism was studied through two important adsorption isotherm models (Langmuir and Freundlich models). Under the optimal experimental conditions, the detection limit was found to be 0.94 µg mL−1 for Rhodamine adsorption. The limit of quantification and the linear range of calibration curve were 3.14 µg mL−1 and 1.00–10.98 µg mL−1, respectively.

In this paper, the proposed method has been introduced for qualitative and quantitative determination of micropore volume in nano ZSM-5 zeolite samples based on diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy along with chemometric methods. For this purpose, a total of 72 samples were provided and DR-FTMIR spectra corresponding to the samples were obtained in the range of 400–4000 cm−1. In order to estimate total surface area from a nitrogen adsorption isotherm, Brauner Emmett Teller (BET) method as a reference method was used. The results are displayed that the significant adsorption peak of the mid-IR spectroscopy in 3660 cm−1 is corresponded to the Si OH groups of the zeolite external surface that is a criterion for the intensity of the mesoporosity. The intensity of the 3745 cm−1 peak is grown up with enhancing the external surface area. These changes were evaluated by non-negative matrix factorization -alternating least squares (NMF –ALS) chemometrics approach for estimating the microporosity in nano ZSM-5 zeolite samples. Back-propagation artificial neural network (BP-ANN) as a nonlinear multivariate regression technique was also used to determine the micropore volume of zeolites based on DRIFT spectroscopy. For BP-ANN model in these samples, R and minimum mean squared error (MSE) values of the testing set data with 5 hidden nodes were 9.95 × 10−1 and 4.11 × 10−7, respectively. The achieved results are presented that DRIFT spectroscopy coupled with chemometrics approaches is a precise, explicit and easy technique to analyze the volume of the micropore in ZSM-5 nano-catalyst samples.

Over the last decade, nanocomposite hydrogels have been provided a new approach for the biomedical field. In this work, a novel pH-responsive nanocomposite hydrogel was fabricated using simultaneous in situ formation of magnetite iron oxide nanoparticles and hydrogel networks of poly(acrylic acid) grafted onto chitosan. The effects of various types of precursor molecules, pH, salt, and loading pressure were examined on the swelling properties of resulting nanocomposite hydrogels. The synthesized nanocomposite hydrogel was well characterized using different instruments. In vitro drug releasing behavior of doxorubicin was studied at pH 5.4 and 7.4. The drug release mechanism was investigated through different kinetic models. These experimental results open a new opportunity to make pH-responsive nanocomposite hydrogel devices for controlled delivery of drug.

In this work, water soluble CdTe quantum dots (QDs) were incorporated into a biopolymeric matrix of polyacrylamide grafted onto cationic starch (CS‐g‐PAAm) to enhance optical properties of QDs. To this aim, the effect of various factors such as AAm concentration, molar ratio of CS‐g‐PAAm/CdTe, reaction temperature and time on optical properties of obtained QDs were investigated via UV‐visible (UV–vis) and fluorescence spectra. Finally, the optimized QDs were characterized by Fourier transform infrared (FT‐IR), transmission electron microscopy (TEM), thermo‐gravimetric (TG) analysis, and energy dispersive X‐ray analysis (EDX).

The inclusion of a polyamidoamine dendrimer in a silica sol-gel yielded a solid nanosorbent that was used for the preconcentration, extraction, and determination of citalopram in hospital waste water, hemodialysis solution, and some drinking water. The method was developed by applying a novel nanosorbent for the solid-phase microextraction of citalopram, containing a silica sol-gel reinforced by polyamidoamine second-generation dendrimer, which was protected by a polypropylene hollow fiber. Plackett-Burman design and central composite design were utilized to evaluate the significance of several factors on the extraction efficiency. The adsorption mechanism and thermodynamic and kinetic aspects were studied. The adsorption process was exothermic and well fitted to the Bangham equation kinetic model. Under optimal conditions, the presented method was liner in the range of 0.05-100 μg/mL. The limits of detection of quantification of citalopram were 0.0095 and 0.031 μg m/L, respectively.

A type of novel nanocomposite was successfully synthesized by embedding glutathione capped CdTe/ZnS QDs into sodium alginate biopolymer. The prepared nanocomposite was characterized using transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FT-IR), fluorescence, and UV–vis spectroscopy. When the obtained nanocomposite interacted with amantadine, its fluorescence intensity was effectively quenched. Under the optimized conditions, the as-prepared nanocomposite provided an efficient platform for detection of amantadine drug within a linear range of 3.1–27.9 × 10−6 mol/L with a detection limit of 0.09 × 10−6 mol/L. Because of the satisfactory results for amantadine determination in real samples, it is confirmed that the synthesized nanocomposite is attractive and reliable for use in biological detection and related fields.

To develop more effective drug delivery systems, a novel thermo sensitive nanogels (TNGs) were prepared by crosslinking of NIPAM graft copolymerization onto salep modified graphene oxide (SMGO). The sizes of as-synthesized TNGs were about 93 nm. It was found that the concentration of GO, surfactant, and polymerization agent were strongly effected on the average size of TNGs. Besides, obtained TNGs display thermo-induced transmittance due to thermo-responsive PNIPAM contained in synthesized TNGs. Moreover, the TNGs presented high drug loading capacity and excellent drug release at higher temperate, without any burst release. It was also demonstrated that the loading drug onto TNGs greatly decreased the cytotoxicity of the drug onto HeLa cells. The results offered evidence that SMGO-based TNGs can serve as novel nanocarriers for anti-cancer drug delivery.

In this manuscript, synthesis, characterization, swelling behavior, and drug delivery performance of a gold nanocomposite hydrogel (GNH) based on poly(acrylic acid) grafted onto salep, as a biocompatible polymer, are described. Gold nanoparticles (AuNPs) as nanometer base, ammonium persulfate as an initiator, N,N-methylenebisacrylamide as a crosslinker, and acrylic acid as pH sensitive monomer were employed for the preparation of entitled GNH in aqueous solution and their amounts were optimized to reach the highest water absorbance. The synthesized GNHs were fully characterized by using FTIR spectroscopy, thermogravimetric analysis, EDAX spectrum, SEM, TEM, and AFM images, and a mechanism for superabsorbent hydrogel nanocomposite formation was suggested. Swelling kinetics in double-distilled water and the absorbency were also investigated. Furthermore, the on–off switching behaviors of the nanocomposite at different pHs were investigated. Doxorubicin hydrochloride is a chemotherapeutic drug and a hydrophilic molecule, with nitrogen and oxygen in its chemical structure. Because nitrogen and oxygen can bind to gold surfaces with high affinity, most frequently nitrogen- and oxygen-modified ligands are used as stabilizing agents, which interact with the surface of the AuNPs by formation of Au–nitrogen and Au–oxygen bonds. This Au nanoparticle–drug conjugate can be incorporated into the bio-based hydrogel matrices to make a hydrogel nanocomposite system. The pH response of this GNH makes it suitable for acting as a controlled drug delivery system. Furthermore, the role of AuNPs in effective release of doxorubicin is discussed by comparing the release in hydrogel and nanocomposite systems.

In this work, we have successfully modified aqueous CdTe quantum dots (QDs) by a biopolymer based on poly (2-hydroxyethyl methacrylate) grafted onto salep via a facile method at room temperature. The obtained QDs were characterized using Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TG), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The size of the prepared QDs was estimated around 1.5 nm by TEM and XRD. Optical properties of modified QDs were monitored by absorption and fluorescence spectrophotometers. It was found that the fluorescence intensity of CdTe QDs was enhanced after coating by biopolymer. Finally, the fluorescence intensity of CdTe QDs was investigated at different temperatures and times.

The principal available methods for the preparation of high quality CdSe quantum dots (QDs) are based on organic ligands such as tri-n-octylphosphine oxide (TOPO) which lead to non-water soluble nanocrystal QDs. As most biological interactions take place in aqueous media, much effort has been made on preparation of water soluble QDs. In this report, the water soluble CdSe QDs were prepared via a ligand exchange process between organic soluble CdSe-TOPO quantum dots and poly(acrylic acid). The poly(acrylic acid) (PAA) can attach onto the surface of CdSe-TOPO quantum dots in a ligand exchange process to make water-soluble CdSe-PAA complexes. In spite of CdSe-TOPO QDs, the resultant CdSe-PAA QDs are soluble in polar solvents such as methanol or water. Optical properties of CdSe-PAA QDs in several solvents showed that the emission intensity of QDs was mainly decreased in protic solvents such as methanol or water. The TEM images of dots in different solvents were examined and some aggregation of dots was found in protic solvents. In comparison with PAA, the addition of PDMAEMA to the solution of CdSe-TOPO QDs in THF increased the emission intensity of QDs. Furthermore, we found that the entitled ligand exchange process was fast and conjugation process completed at short time intervals. The UV-irradiation of the CdSe-PAA conjugate in water showed that the emission was amplified by increasing the irradiation time.

In this study, the synthesis and characterization of a novel nano-porous superabsorbent hydrogel with high water swelling capacity is described. A nano-porous hydrogel was prepared by employing (2-dimethylaminoethyl) methacrylate (PDMAEMA) as a pH sensitive monomer and sodium alginate (SA) as a water soluble polysaccharide under γ-ray irradiation. The polymerization reaction was performed at room temperature in the absence of chemically toxic crosslinking agent and initiators. The interactive parameters including biopolymer backbone concentration, monomer concentration and γ-irradiation dose were selected as major factors in the synthesis of superabsorbent and three levels for each factor were applied to obtain the highest water swelling according to the central composite design (CCD) method. According to the results of nine different tests which were derived by CCD method, the optimum conditions were determined. The results showed that the hydrogel prepared at concentration of 1.5 g SA, 2.1 mol/L PDMAEMA and at a radiation dose of 5 kGy displayed the highest swelling capacity. In continuation, the effect of salt, pH, and particle size on the swelling behavior of the obtained samples was investigated. We found that the swelling of the optimized sample first increased and then dropped with increases in pH from 2 to 12 and the maximum water absorbency was observed at pH 7. Finally, different techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscope (SEM) were applied for the characterization of optimized nano-porous hydrogel.

A novel nano-porous hydrogel (NPH) was synthesized via graft copolymerization of sodium acrylate (Na-AA) and acrylamide (AAm) onto salep backbones and its application as a carrier matrix for oral delivery of tetracycline hydrochloride (TH) was investigated. The Taguchi method as a strong experimental design tool was used for synthesis optimization. The swelling behavior of optimum hydrogel was measured in various media. The hydrogel formation was confirmed by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetrical analysis (TGA). The study of the surface morphology of the hydrogels using SEM and AFM showed a nanoporous (average pore size: 180 nm) structure for the sample obtained under optimized conditions. The drug delivery results demonstrated that this NPH could successfully deliver a drug to the intestine without losing the drug in the stomach, and could be a good candidate as an orally administrated drug delivery system.

A new fluorescent composite based on CdS quantum dots immobilized on the multidentate biopolymer matrix is prepared through the graft copolymerization of the acrylamide onto kappa-Carrageenan. A variety of techniques like thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) was used to confirm the structure of the obtained samples. To investigate the spectrofluorometric properties, fluorescence spectroscopy of the obtained quantum dots was studied.

We report that sodium alginate and its graft-copolymers with (2-dimethylaminoethyl) methacrylate may attach to the surface of colloidal CdS–thioglycerol quantum dots (QDs) via a ligand exchange process and result in water-soluble and highly stable QD supramolecules. Optical properties of modified QDs in water showed that the emission intensity of QDs was still high after surface passivation.

A novel kind of a biopolymer-based superabsorbent composite, salep-g-poly(sodium acrylate)/alumina, was prepared from salep, sodium acrylate, and alumina by aqueous polymerization, using N,N′-methylenebisacrylamide (MBA) as a cross-linker and ammonium persulfate (APS) as an initiator. The reaction parameters [i.e., acrylic acid (AA), MBA, APS amounts, and neutralization percentage of AA as well as alumina/salep weight ratio] affecting the water absorbency of the hydrogel composite were optimized using systematic method to achieve a composite with high swelling capacity as possible. The swelling behavior of optimum superabsorbent composite was measured in various pH solutions. In addition, swelling kinetics, swelling in various NaCl concentrations, swelling in various solvents, and the absorbency underload were investigated. Also, pH-reversibility and the on–off switching behaviors of the composite in various environments were investigated. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 31: 41–51, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20233

In this work, CdSe quantum dots (CdSe QDs) were successfully synthesized and embedded in a biopolymer based on poly((2-dimethylaminoethyl) methacrylate) grafted onto kappa-Carrageenan (κC) via a facile process. The synthesized samples were studied by transmission electron microscopy (TEM) and it showed that the CdSe quantum dots have an average size of around 3.5 nm which were dispersed in the biopolymer matrix. Fourier transform infrared spectrum (FT-IR) was used to characterize the functional groups on the surface of QDs and the structure of biopolymer samples. UV–vis and FL spectra were employed to study the optical properties of QDs before and after ligand exchange with modified κ-Carrageenan biopolymers. The obtained samples showed significant improvement in their thermal behavior as indicated by thermo gravimetric analysis (TGA). Lastly, the effect of some factors on the fluorescent properties of CdSe quantum dots has been investigated to obtain QDs with highest fluorescent intensities.

A novel high capacity swelling nanoporous hydrogel (NPH) was synthesized via graft copolymerization of acrylamide (AAm) onto kappa-carrageenan (kC, as a polysaccharide) and gelatin (as a protein) hybrid backbone, after hydrolysis of this system. The Taguchi method as a strong experimental design tool was used for its optimized synthesis. The Taguchi method was applied for the experimental and standard 9 orthogonal array (OA) with four factors and three levels for each factor. A series of NPHs were synthesized by proposed conditions of Qualitek-4 Software. Considering the results of 9 trials according to analysis of variance (ANOVA), optimum conditions were proposed. The swelling behavior of optimum NPHs was measured in various solutions with pH values ranging from 1 to 13. In addition, swelling kinetics, swelling in various organic solvents and various salt solutions were investigated. The hydrogel formation was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetrical analysis (TGA). The study of the surface morphology of hydrogels using SEM showed a highly nanoporous and cellular structure for the sample obtained under optimized condition.

The synthesis of a novel superabsorbent hydrogel with natural hybrid backbone via graft copolymerization of acrylamide (AAm) onto kappa-carrageenan (kC, as a polysaccharide) and gelatin (as a protein) under classic thermal conditions is described. The Taguchi method as a strong experimental design tool was used for synthesis optimization. A series of hydrogels were synthesized by proposed conditions of Qualitek-4 Software. Considering the results of 9 trials according to analysis of variance (ANOVA), optimum conditions were proposed. The swelling behavior of optimum hydrogel was measured in various solutions with pH values ranging from 1 to 13. In addition, swelling kinetics, swelling in various organic solvents, various salt solutions and On–Off switching behavior were investigated. The hydrogel formation was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetrical analysis (TGA). Surface morphology of the synthesized hydrogels was assessed by scanning electron microscope (SEM).

Synthesis and swelling behavior of a new superabsorbent hydrogel based on natural salep grafted with polyacrylamide is described. The new superabsorbent hydrogel biopolymer was synthesized via radical crosslinking and graft copolymerization of acrylamide monomer onto salep backbones. Regarding to the water absorption of hydrogel, the best synthesis condition is reported. FTIR spectroscopy and thermogravimetric analysis were used to confirm the structure of the final product and a mechanism for superabsorbent hydrogel formation was also suggested. After preparing the desired hydrogels based on optimum condition, several factors affecting the swelling behavior of hydrogel including pH of medium, sensitivity to the salt solution, and mixture of solvents were studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

In this report, the synthesis of a novel superabsorbent hydrogel via γ-irradiation graft copolymerization of acrylamide onto sodium alginate and kappa-carrageenan hybrid backbones in a homogeneous solution is described. The Taguchi method was used as a powerful experimental design tool for synthesis optimization. A series of superabsorbent hydrogels was synthesized by proposed conditions of Qualitek-4 software. Considering the results of nine trials according to analysis of variance, optimum conditions were proposed. The swelling behavior of optimum superabsorbent hydrogels was studied in various solutions, with pH values ranging from 1 to 13. In addition, swelling kinetics, swelling in various organic solvents, the absorbency under load, and on–off switching behavior were investigated. Also, hydrogel formation was confirmed by Fourier transform infrared spectroscopy. Surface morphology of the synthesized hydrogels was assessed by scanning electron microscopy. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 28:131–140, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20154

Poly(butyl methacrylate) (PBMA) latex particles have been copolymerized with new fluorescent naphthalimide dyes by miniemulsion polymerization. A new pair of naphthalimide dye monomers was synthesized and copolymerized with butyl methacrylate (BMA) via miniemulsion polymerization, producing approximately 80 nm diameter particles with a narrow size distribution. We were able to prepare polymers with molecular weights in excess of 100,000 g/mol. We also prepared 30,000 g/mol polymers using 1-dodecanethiol as a chain transfer agent. GPC and UV characterization suggest that nearly all of the dye monomers were incorporated into the PBMA polymer chains. The polymerized naphthalimide dyes can be used as a donor–acceptor pair for fluorescence resonance energy transfer (FRET) experiments. The analysis of FRET experiments is complicated by the slightly non-exponential decay of the donor naphthalimide dye. We propose a simple method to deal with this non-exponential behavior in the data analysis. Using our approach, we find that the Forster radius (Ro) between the donor and the acceptor dyes incorporated in the PBMA latex is 3.8 nm. This value is similar to the 3.6 nm Forster radius of a comparable model dye pair in ethyl acetate obtained by a different method.

We measured the fluorescence decays of seven different amino-coumarin dyes in polymer films of poly(methyl methacrylate) (PMMA), poly(styrene) (PS), and ethylene-butene rubber (EBR); as well as in the small molecule analogs ethyl acetate and toluene. Many of the dye-solvent and dye-polymer combinations exhibited single exponential decays with lifetimes ranging from 2.3 to 3.9 ns. Small deviations from single exponential behavior occurred for most of the dyes in EBR. Significant deviations from single exponential behavior occurred for 7-(diethylamino)-2-oxo-2H-1-benzopyran-3-carboxylic acid (coumarin-3) in ethyl acetate and in all polymer matrices and 2,3,6,7-tetrahydro-11-oxo-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-10-carboxylic acid (coumarin-343) in all of the polymer matrices. Time-resolved fluorescence spectra indicated the presence of two different excited states for coumarin-3 and coumarin-343 in PMMA; these spectra were qualitatively different from the time-resolved spectra of coumarin-3 in ethyl acetate. We rationalize these results in terms of the chemical functionalities of the various dyes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2333–2343, 2007

In this paper, a novel biocompatible magnetic iron oxide nanoparticles/hydrogel was synthesized based on the simultaneous formation of magnetic iron oxide nanoparticles (MION) and hydrogel based on poly (acrylic acid) grafted onto starch (PAA-g-starch). The structural, morphological and magnetic properties of the optimized sample were characterized by scanning electron microscopy with energy dispersive X-ray analysis (SEM–EDAX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM). In addition, the effect of external magnetic field (EMF), pH, and temperature on the swelling of the MION-PAA-g-starch hydrogel was studied. The results showed that the EMF reduced the swelling capacity of MION-PAA-g-starch hydrogel. Moreover, the in vitro release of deferasirox was studied in pH = 2 and 7 under EMF. The release curves were nicely fitted by the Korsemeyer–Peppas equation and the release followed by non-Fickian diffusion.

This work describes synthesis of biocompatible magnetic iron oxide nanoparticles/hydrogel based on salep (MION–salep hydrogel) by a facile one-pot strategy. The prepared sample was characterized by techniques like scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDAX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM). The obtained MION had an 8 nm diameter with a narrow size distribution and was superparamagnetic with large saturation magnetization at room temperature. The most attractive feature of the obtained sample was its swelling properties under external magnetic field (EMF), different temperatures, and pHs. Moreover, MION–salep hydrogel showed ability to deferasirox release at pH = 7 with non-Fickian diffusion mechanism. An in vitro cytotoxicity study implied that the as-synthesized sample is nontoxic.

A novel potentially biocompatible nanoporous hydrogel was synthesized via crosslinking graft copolymerization of (2-dimethylaminoethyl) methacrylate (DMA) monomer onto salep backbones. Methylenebisacrylamide (MBA) and ammonium persulfate (APS) were applied as water-soluble crosslinker and initiator, respectively. To investigate the structure of the obtained hydrogel, fourier transforms infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA) and scanning electron microscopy (SEM) were used. Swelling behavior of the obtained hydrogel at different temperatures and pH media was investigated and it was found that the synthesized hydrogel has a high sensitivity to pH. The swelling first increased and then decreased with increasing pH from 2 to 12 at 37 °C and the maximum water absorbency was observed at pH = 8. Swelling reversibility of the hydrogel at pH 2.0 and 8.0 was examined to show the pH sensitivity and smartness of hydrogel. Lastly, the potential use of this hydrogel for the loading and releasing of tetracycline hydrochloride (TH) as a model drug was examined. The results showed that 95 % of TH was released at pH 8 after 4 h at 37 °C which were best fitted with Korsmeyer kinetic model.

Poly ((2-dimethylaminoethyl) methacrylate) grafted onto κ-carrageenan (κC-g-PDMA) as a biopolymer was synthesized and applied for surface modification of water-soluble CdTe quantum dots (QDs). The effects of DMA concentration, molar ratio of κC-g-PDMA/CdTe, reaction temperature and time on optical properties of CdTe QDs were investigated via fluorescent (FL) and UV- visible spectra. The results showed that the κC-g-PDMA significantly affects the optical properties of CdTe QDs. The obtained samples were characterized by Fourier transform infrared spectrum (FT-IR), thermogravimetric (TG) analysis, and transmission electron microscopy (TEM). The antibacterial activity, antifungal assays, and cytotoxicity of modified QDs were examined, and a good biocompatibility was observed.

We report a simple, fast, efficient and benign procedure for solvent-free microwave-assisted one-pot synthesis of symmetrical 4H-pyran-4-ones in the presence of polyphosphoric acid or diphosphorous pentoxide. Various 4H-pyran-4-ones were prepared using this very simple and fast green protocol. Descrevemos um procedimento simples, rápido, eficiente e benigno para a síntese assistida por microondas, sem o uso de solvente, de 4-piranonas simétricas na presença de ácido polifosfórico ou pentóxido de fósforo. Diversas 4-piranonas foram preparadas por esse método simples e rápido.

The optical properties of CdSe quantum dots (QDs) capped by thioglycolic acid (TGA) before and after surface modification with poly (acrylic acid) grafted onto salep (salep-g-PAA), as a biopolymer-based multidentate ligand, were examined. The results showed that the fluorescence intensity as well as the stability of CdSe QDs was incredibly increased after surface modification with the biopolymer-based ligand. To provide more evidence for the occurrence of surface modification, the prepared CdSe –salep-g-PAA QDs were characterized by thermo-gravimetric analysis (TG), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR).

A facile procedure for the coating of CdTe quantum dots (QDs) by a natural biopolymer based on polyacrylamide (PAAm) grafted onto kappa-carrageenan (κC-g-PAAm) is introduced. Transmission electron microscopy images revealed that the QDs are nearly spherical in shape with average diameter of ~2.4 nm. The optical property of QDs was studied by the UV-visible spectrum. The biomolecules were used to investigate their influence on the fluorescence intensity of nanocrystals. Fourier transform infrared spectroscopy study suggested QDs can interact with functional groups of biopolymer including its hydroxy and amide groups.