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Magnetic nanoparticles (MNPs) have many unique properties such as non-toxicity, suitable thermal and chemical stability, designability for different applications, environmental friendliness, high s...

Antibacterial photodynamic therapy (aPDT) has drawn increasing attention as a noninvasive approach to remove bacterial contaminants such as E. faecalis from the tooth surface. In this study, curcumin (CUR) was loaded into ZSM-5 zeolite and the prepared photosensitizers (CUR@ZSM) were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet–visible spectroscopy (UV–Vis). The loading efficiency, and release behavior of CUR were studied in CUR@ZSM. The antimicrobial and anti-biofilm potential of the photosensitizer were evaluated against E. faecalis via colony forming unit and crystal violet assays, respectively. No significant changes were observed in the size, morphology and crystallinity of the zeolite after CUR loading. CUR@ZSM showed a significant photodynamic inactivation effect through complete bacterial elimination and reduced the biofilm formation ability of E. faecalis up to about 80%. The results revealed that CUR@ZSM could be considered as a new potential photosensitizer for further study against endodontic infections.

Epirubicin (EPI) is one of the standard anticancer drugs that apply for various cancers treatment. However, the accumulation of EPI in the human body can be highly toxic, and it causes inevitable harm to organs. As a result, the evaluation of low concentrations of this drug in body samples requires sensitive, rapid, and accurate analysis methods. The fluorescence method is an efficient way in comparison of the traditional methods such as liquid chromatography, capillary electrophoresis, and electrochemical methods. Herein, we synthesized a novel fluorescence nanosensor named CMC-CdTe/ZnS based on using quantum dots (QDs). The structure of the prepared nanosensor is confirmed by different analysis methods such as FT-IR, TGA, and TEM. Besides that, the fluorescence intensity response of CMC-CdTe/ZnS QDs in the presence of Epirubicin drug is 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 nanosensor in the presence of Epirubicin is F0/F = 0.0346Q + 1.08 (R2 = 0.99), and the detection limit of Epirubicin is around 0.04 × 10−6 mol/L at 25 °C. All of the results display that this method could be reliable and suitable approach for determination of Epirubicin in commercial samples as well.

Due to the increasing demand for monitoring diseases such as rising heart rate, diabetes, and ocular disorders wearable and implantable biomedical devices seems too essential for patients not only in the hospital but also at home or during working time. Researchers mostly try to offer valuable information on the conditions of patients as non-invasive, by using comfort biomedical device with a minimum side effect. So, small and self-powered with high sensitivity biomedical devices are recommended, among different power sources that introduced for devices, biofuel cells would be produced as power source for a range of medical devices because of its capability to generate sufficient power output compared to the primary power source. The nature of the electrode reaction and the nature of the biochemical reactions are some of the important parameters that are considered for the classification of fuel cells. Enzymatic biofuel cells due to high activity at mild conditions widely applied in pacemaker; glucometer; and smart contact lenses when compared to other kinds of biofuel cells. On the other hand, short lifespan is one of important limitations in this type of biofuel cells. So, the easiest way to overcome these challenges is to apply non-enzymatic ones. Recent studies have attempted to issue novel method for fabrication of non-enzymatic biofuel cell in order to produce a new generation which are inexpensive, disposable, selective, and sensitive in properties. However, consideration of researchers to the development of self-powered biomedical devices by using body fluids or providing electricity storage is rising.

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.

An environmentally friendly, straightforward, and cheap synthesis of highly substituted functionalized pyrrole derivatives via one pot four-component reactions of 1,3-dicarbonyl compounds, amines, ...

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.

This paper describes the synthesis and characterization of a pH-responsive drug release system based on cadmium telluride quantum dots capped by fluorescent dye-labeled poly (N-(2-(2-amino-ethylamino)-ethyl methacrylamide) metal-chelating polymer. Fluorescent dye is a model for an active molecule which shows our polymer can be attached to bioactive agents such as antibody or a functional drug. Furthermore, it indicates the success of ligand exchange between anchor groups on polymer surface and QDs. The polymer was synthesized using reversible addition fragmentation chain transfer polymerization, resulting in polymers with controllable molecular weights and low polydispersities. The use of diethylenetriamine allows obtaining hydrophilic polymers with amine functional groups available for conjugation with QDs. Furthermore, the amine moieties of the polymer guarantee the pH sensitivity of the system. The obtained nano carrier was monodispersed with very small diameter around 4.5 nm which confirmed by TEM. The obtained nanoparticles show low cytotoxicity in cell viability studies. The release rates of doxorubicin (DOX) anticancer drug conjugates were studied at pH 5.4 and pH 7.4. The release behavior for DOX in pH 7.4 (pH of normal cells) is

A novel optical nano-sensor for tetracycline hydrochloride (TH) detection as a small molecule model was prepared by modifying the surface of CdTe/ZnS QDs with a biopolymer based cap, called poly ((2-dimethylaminoethyl) methacrylate) grafted onto oxidized starch (OS-g- PDMAEMA), via a facile method. The preparation of the nano-sensor was optimized by employing a 4-factor Box–Behnken statistical design to achieve a nano-sensor with maximum fluorescence intensity for sensitive determination of TH in real samples. The optimized nano-sensor based on CdTe/ZnS QDs were characterized by fluorescence spectroscopy, UV–vis spectrophotometry, transmission electron microscopy (TEM), Fourier transforms infrared (FTIR) and thermo-gravimetric (TG) analysis techniques. It was found that the fluorescence intensity of modified QDS (CdTe/ZnS-OS-g-PDMAEMA QDs) at 520 nm (excitation at 375 nm) was selectively quenched in the presence of trace amounts of TH drug. In this method, a simple, highly sensitive, selective and rapid analytical approach was used for the determination of TH in the concentration range of 9.14 × 10−9 mol L−1–7.23 × 10−6 mol L−1 with a detection limit of 2.74 × 10−9 mol L−1. The designed nano-sensor can be successfully applied for the determination of TH in complex matrixes (pharmaceutical formulations, urine, saline and glucose serums) with satisfactory analytical results.

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)).

Herein, thermo/pH/magnetic-triple sensitive nanogel comprised of poly(N-isopropylacrylamide), poly(2-dimethylaminoethyl) methacrylate), sodium alginate, and magnetic graphene oxide were synthesized using N,N-methylenebisacrylamide as a crosslinking agent, sodium dodecylsulfate as a surfactant, and ammonium persulfate as an initiator. The size, chemical structure, thermal stability, and morphology of the prepared nanogel were characterized using different methods. Transmittance of the obtained nanogel was investigated at varying pH and temperature in the presence and absence of magnet. The drug loading ability of synthesized nanogel was examined at different times and concentrations of doxorubicin. Additionally, the release rate of doxorubicin as an anticancer drug from the loaded nanogel was studied at different pH and temperature in the presence and absence of magnet. The biological performance of the formed nanogel was evaluated by seeding it onto MCF-7 cells at different times and concentrations. It was found that this triple responsible nanogel might provide a perfect basis for controlled drug delivery systems.

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 work, as a novel fluorescent nano-sensor, a ligand-capped CdTe QDs (CdTe-L QDs) was designed for the detection and quantification of Cu2+ ions in environmental water samples. The synthesized QDs were characterized by transmission electron microscopy (TEM), thermo-gravimetric (TG) analysis, Fourier transform infrared (FTIR), UV–Vis spectrophotometry and fluorescence spectroscopy. Optical properties of the produced nanosensor were monitored by UV–Vis and fluorescence spectrophotometry. It was observed that fluorescence intensity of the produced nano-sensor selectively quenched by adding Cu2+ ions in comparison to other metal ions tested. Using CdTe-L QDs, a rapid and facile analytical method was developed to determine Cu2+ ions in the concentration range of 5.16 ± 0.07 × 10− 8 mol L− 1–1.50 ± 0.03 × 10− 5 mol L− 1 with a detection limit of 1.55 ± 0.05 × 10− 8 mol L− 1. The nanosensor was successfully applied for the determination of Cu2+ ions in various water samples, and the results were compared with the standard method.

In the present study, a hydrothermal method was developed to prepare nalidixic acid-loaded [Zn2(bdc)2(dabco)] metal–organic frameworks. The self-assembly of primary building blocks was used for synthesis of [Zn2(bdc)2(dabco)] at room temperature. The zinc metal ion was used as a connector, 1,4-benzenedicarboxylate (bdc) as a chelating ligand, and 1,4-diazabicyclo[2.2.2]octane (dabco) as a bridging ligand. The metal organic frameworks were used as the carriers for drug delivery system, where it could entrap nalidixic acid as a model drug. X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), ultraviolet-visible spectroscopy (UV–vis), BET nitrogen adsorption–desorption method, and scanning electron microscopy (SEM) were used for characterization of samples. The drug release was also monitored, and 96 and 62% of the loaded drug were released over 120 h at pH values of 5.0 and 7.4, respectively. The antimicrobial activities of [Zn2(bdc)2(dab...

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.

Green chemistry is one of the most important routes for the synthesis of heterocyclic compounds. In this regard, the synthesis of 2-thioxoquinazolinone derivatives was achieved by condensation of versatile materials including isatoic anhydride, amine and potassium thiocyanate in the green medium of water. This convenient and efficient method affords the desired products with good to excellent yields.

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 present study investigated antibiotic drug loading in metal–organic frameworks (MOFs). Porous zeolitic imidazolate frameworks (ZIFs) were synthesized under concentrated aqueous solution. A straightforward nano-precipitation method was used to prepare ciprofloxacin (CIP)-loaded ZIF-8 (CIP-ZIF-8). ZIF-8 and CIP-ZIF-8 were characterized by FT-IR spectroscopy, X-ray powder diffraction, scanning electron microscopy, thermogravimetric analysis, the BET nitrogen adsorption–desorption method, and UV-Vis spectroscopy. The thermal behavior of CIP-ZIF-8 was confirmed by thermal analyses. FT-IR spectroscopy illustrated the presence of functional groups of CIP and ZIF-8 frameworks in CIP-ZIF-8. ZIF-8 showed high loading capacity for the model antibiotic drug CIP with pH-sensitive release. The as-synthesized CIP-ZIF-8 possesses high drug loading efficiency (21%), and the release in pH 5.0 acetate buffer solutions (97%) was faster than in pH 7.4 phosphate buffers (83%). The antibacterial activities of ZIF-8 and CIP-ZIF-8 were tested against one Gram-positive and one Gram-negative species. The results showed that the synthesized materials had good growth inhibition against microorganisms.

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.

A polyacrylamide grafted onto kappa-carrageenan biopolymer (κC-g-PAAm) was successfully synthesized and employed for coating of CdS quantum dots (QDs) in aqueous solutions. The as-obtained QDs were...

A new preconcentration method, magnetic dispersive micro solid phase extraction (MDMSPE) developed for separation and determination of mercury. In this technique, an appropriate mixture of extraction solvent, disperser solvent and nanomagnetite (Fe 3 O 4 )/chelating agent 1-(2-ethoxyphenyl)-3-(4-ethoxyphenyl) triazene functionalized multi-walled carbon nanotubes with silica shell, as an adsorbent injected rapidly into an aqueous solution containing mercury. After the proper contact time, the nano-adsorbent separated from the aqueous phase by applying magnetic field outside of the vial and transferred to another vial with the elution solvent. The residual solution determined by cold vapour atomic absorption spectroscopy. The main factors affected the preconcentration of mercury investigated and optimized, such as extraction and disperser solvent type, adsorbed amount, sample pH value, effluent concentration, extraction time, the volume of chelating agents and temperature. The adsorption equilibrium data obeyed the Langmuir isotherm models and the kinetic data were well suited to the pseudo-second-order model. Thermodynamic studies revealed the endothermic nature of the procedure. Under the optimum experimental conditions, the detection limit for Hg(II) found to be 1.5 ± 0.27 ng mL − 1 and its limit of quantification (LOQ) was 5.0 ± 0.32 ng mL − 1 (n = 5). The linear range of the calibration curve was 9 ± 0.51–1000 ± 0.03 ng mL − 1 with a correlation coefficient of 0.9994.

A novel CdTe quantum dots (QDs) were prepared in aqueous phase via a facile method. At first, poly (acrylic amide) grafted onto sodium alginate (PAAm-g-SA) were successfully synthesized and then TGA capped CdTe QDs (CdTe-TGA QDs) were embed into it. The prepared CdTe-PAAm-g-SA QDs were optimized and characterized by transmission electron microscopy (TEM), thermo-gravimetric (TG) analysis, Fourier transform infrared (FT-IR), UV-vis and fluorescence spectroscopy. The characterization results indicated that CdTe-TGA QDs, with particles size of 2.90 nm, were uniformly dispersed on the chains of PAAm-g-SA biopolymer. CdTe-PAAm-g-SA QDs also exhibited excellent UV-vis absorption and high fluorescence intensity. To explore biological behavior of CdTe-PAAm-g-SA QDs, the interactions between CdTe-PAAm-g-SA QDs and human serum albumin (HSA) (or bovine serum albumin (BSA)) were investigated by cyclic voltammetry, FT-IR, UV-vis, and fluorescence spectroscopic. The results confirmed the formation of CdTe-PAAm-g-SA QDs-HSA (or BSA) complex with high binding affinities. The thermodynamic parameters (ΔG

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.

Benzimidazoles, benzoxazoles, and benzothiazoles derivatives were synthesized from condensation of aldehydes and 1,2-phenylenediamine or ortho -aminophenol or ortho -aminothiophenol in the presence of catalytic amount of Fe(III)–Schiff base/SBA-15 in water medium. Short reaction times, good to excellent yields, easy availability, reusability, and use of an eco-friendly catalyst are some of the significant attributes of the present method.

Solvent-free organic reactions were studied over periodic mesoporous silica (SBA-15) containing a Cu(II) organometallic complex. This heterogeneous catalyst was achieved by coordination of Cu(II) ions with the diaminosarcophagine ligand and then its grafting onto the surface of SBA-15. This catalyst displayed ordered mesoporous channels, which implies an extremely high dispersion of the Cu(II) complex and the convenient diffusion of reactant molecules into the pore channels. Therefore, this catalyst can offer high activity and also facile separation or recycling when compared with its homogeneous counterparts. Copyright © 2015 John Wiley & Sons, Ltd.

A novel CdS quantum dots (QDs) were successfully synthesized in aqueous phase using poly (acrylic acid) grafted onto starch (starch-g-PAA). UV–vis spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) techniques proved that the prepared starch-capped CdS QDs are composed of a CdS core and a polymeric shell with homogeneous size distributions. In order to study its biological behavior, multi-spectroscopic techniques were adopted to investigate their conjugation with human serum albumin (HSA) and bovine serum albumin (BSA) proteins. The recorded UV–vis spectra, cyclic voltammetry (CV) analysis, and the calculated rate of HSA and BSA fluorescence quenching by the QDs demonstrated that the interaction between them leads to the formation of QDs-HSA and QDs-BSA complexes. Moreover, FT-IR spectra showed the conformational changes of the protein in the presence of obtained QDs, indicating the presence of interaction between modified QDs and proteins.

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).

We describe the synthesis of an end-functionalized fluorescent dye-labeled poly(N-(2-thiolethyl methacrylamide) as a metal chelating polymer with a very narrow size distribution and controllable molecular weights by reversible addition–fragmentation chain transfer polymerization. In following, we apply this water-soluble metal-chelating polymer for surface modification of cadmium telluride quantum dots (CdTe QDs) by ligand exchange method. The obtained poly(N-(2-thiolethyl methacrylamide)/CdTe QDs hybrid was fully characterized using Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TG) and transmission electron microscopy (TEM). The size of the prepared hybrid was estimated around 3.2 nm by TEM. Furthermore, we used this hybrid for improving the release performance of doxorubicin hydrochloride as a chemotherapeutic model drug. The in vitro release of doxorubicin was studied in pH 5.4 and 7.4, which release curves were nicely fitted by the Korsemeyer–Peppas equation and the release followed by non-Fickian diffusion or anomalous diffusion in pH 5.4. The synthesized fluorescent dye-labeled hybrid can be used as a donor-acceptor pair for fluorescence resonance energy transfer (FRET) experiments, so the energy transfer behavior between fluorescent dye as a donor and CdTe QDs as an acceptor were interrogated using Forster/fluorescence resonance energy transfer model, which the distance was found to be 3.95 nm. This present work has potential for both diagnostic and therapeutic aspects for cancer patients.

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.

In this report, a facile, operationally, simple and highly efficient one-pot coupling of 2,6-diaminopyrimidin-4(3H)-one and ethyl-2,4-dioxo-4-phenylbutanoate derivatives is reported. This method afforded a novel series of ethyl-2-amino-3,4-dihydro-4-oxo-5-phenyl pyrido[2,3-d] pyrimidine-7-carboxylate heterocycle derivatives in high yields under refluxing AcOH.

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.

Two approaches were utilized and compared for designing a novel ultrasensitive fluorescent apta-nanobiosensor for fast and sensitive determination of digoxin (DX) in biological fluids. The nanobiosensors were fabricated using reduced graphene quantum dots (rGQDs) as an optical probe and DX aptamer as a sensing material. In the first approach, a label-free aptamer was directly interacted with rGQDs, caused an enhancement of the fluorescence intensity of rGQDs. By addition of the target molecule (DX) and formation of the aptamer-DX complex, the fluorescence intensity was decreased. The fluorescent quenching had a linear relation with the concentration of DX with limit of detection down to 29.87 ± 1.01 × 10−12 mol L−1. In the second approach, to improve the reproducibility and sensitivity of the biosensor, a labeled aptamer with amine groups was used. Through a two-steps process, DX was detected more accurately. Fluorescence intensity of rGQDs functionalized with aptamer was first turn-off using oxidized carbon nanotubes (CNTs) through a fluorescence resonance energy transfer (FRET) mechanism. Next, by addition of the target molecule (DX), and its interaction with aptamer, inhibited the connection between CNTs and rGQDs-aptamer, hence, fluorescence of rGQDs were recovered and turn-on. The second approach provided a simple, fast, inexpensive, reproducibility and ultrasensitive methods for determination of DX with ultra-low detection limits of 7.95 ± 0.22 × 10−12 mol L−1. Both designed luminescent apta-nanobiosensors were well used for the quantification of DX in human serum and urine with satisfactory analytical results.

In this study, we describe the synthesis of a new quantum dots (QDs) by embedding glutathione capped CdTe/ZnS QDs into cationic starch biopolymer (CS-GSH-CdTe/ZnS QDs). The fluorescence intensity of prepared QDs was significantly enhanced. When QDs interacted with rifampicin, the fluorescence intensity of the CS-GSH-CdTe/ZnS QDs was highly quenched compared with GSH-CdTe/ZnS QDs. Based on the above, a new fluorescent nanosensor for simple, sensitive and selective detection of rifampicin was developed. The fluorescence quenching was well described by the typical Stern–Volmer equation. After optimization, the linear range of the as-prepared QDs fluorescence intensity versus the concentration of rifampicin was F0/F = 0.0422Q + 1.109 (R2 = 0.99). The detection limit was 0.06 × 10− 6 mol/L. The proposed method with satisfactory results was used to detect rifampicin in commercial capsules and tablets.

The asymmetric unit of the title compound, C(8)H(6)N(4), contains two almost planar independent mol-ecules (r.m.s. deviations = 0.026 and 0.030 Å). The crystal studied was a non-merohedral twin with the components in a 0.513 (2):0.487 (2) ratio.