Efficient graphene-coated iron oxide (GCIO) nanoadsorbent for removal of lead and arsenic ions.

ABSTRACTThe graphene-coated iron oxide (GCIO) was used for the removal of Pb2+ and As3+ ions from aqueous solution. For the characterization of GCIO, several techniques (FTIR, XRD, EDX, SEM, TEM, TGA, DSC and vibrating sample magnetometry) were used which indicated the interaction of Pb2+ and As3+ with adsorbent. In addition, the effects of adsorbate concentration, different composition of adsorbent, temperature, pH of the solution and contact time of adsorbate-adsorbent were studied. After analysis of these experiments, it was found that GCIO offered very fast removal of Pb2+ and As3+ with small amount of GCIO (0.09 g) in 100 mg/L adsorbate solution. The maximum removal of Pb2+ ions (up to 97.62%) was achieved when 100 mg/L standard solution of metal ion was treated with GCIO for 35 min at 45°C in weak acidic medium (5 pH). The adsorption of Pb2+ ions followed Freundlich model with high correlation coefficient 0.98 R2. In case of As3+ ions, maximum removal of metal ion (up to 86.62%) was attained when 100 mg/L adsorbate solution is treated with GCIO for 25 min in slightly acidic medium (6 pH) at 25°C. The adsorption of As3+ ions followed D-R model with 0.98 R2 value. The adsorption of both metal ions (Pb2+ and As3+) follows second-order kinetic model. The high percentage removal of metal ions with little quantity of GCIO confirmed that GCIO is an excellent, effective and economic adsorbent.

Nano-silver hydroxyapatite based antibacterial 3D scaffolds of gelatin/alginate/poly (vinyl alcohol) for bone tissue engineering applications.

In the present study macroporous three dimensional spongy scaffolds composed of gelatin, alginate, and poly (vinyl alcohol) were prepared by cryogelation technique and silver hydroxyapatite was reinforced into the 3 D matrix. The polymer nanocomposite materials were characterized by analytical techniques such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and x-ray diffraction (XRD) analysis. The nanocomposite scaffolds were studied for their porous nature, water sorption capacity, and mechanical behavior. The suitability of scaffolds for bone tissue engineering applications was judged by evaluating their antibacterial and cytotoxic nature against gram positive and gram negative bacteria, and MC3T3-E1 preosteoblast cells, respectively. The scaffolds were also studied for release of silver ions and the influence of various experimental conditions on the release profiles of silver ions was investigated.

Reverse indentation size effects in gamma irradiated blood compatible blend films of chitosan-poly (vinyl alcohol) for possible medical applications.

In the present work binary blends of polyvinyl alcohol (PVA) and chitosan (CS) were prepared by solution cast method and characterized by analytical methods like FTIR, XRD and SEM for seeking structural and morphological information. The blends were exposed to gamma radiation and evaluated for their improved mechanical strength. It was found that the tensile strength and microhardness increased after irradiation of CS-PVA films. Plastic effect due to absorption of water molecules and scissoring effect due to gamma irradiation were found to decrease the softness or increase the microhardness of the blends. Improved mechanical properties were attributed to intermolecular and intramolecular hydrogen bonds and adhesive nature of the blends also. The blends were also investigated for water intake behavior and in vitro blood compatibility property on the basis of certain in vitro tests like protein adsorption, haemolysis and blood clot formation on the un-irradiated and irradiated blend samples. The increased % swelling with time could be assigned to the fact that increasing water content facilitates the phase separation process within the blend which results in advancement in interstitial nano-void spaces which are occupied by water molecules. The blood compatibility results showed that when the amount of CS was varied from 0.5% to 2%, the amount of blood clot and percent haemolysis decreased while the protein adsorption increased with increasing CS content of the blend films.

Designing of silk and ZnO based antibacterial and noncytotoxic bionanocomposite films and study of their mechanical and UV absorption behavior.

Bionanocomposites of sericin and polyvinyl alcohol (PVA) were prepared by solution casting method and zinc oxide nanoparticles were impregnated within the polymer blend matrix through homogenous phase reaction between zinc chloride and sodium hydroxide at high temperature following an ex-situ co-precipitation method. The prepared bionanocomposites were characterized using Fourier Transform Infrared Spectroscopy, X-ray diffraction, Field Emission Scanning Electron Microscopy, Transmission Electron Microscopy and Atomic Force Microscopy techniques. The presence of characteristic groups of sericin and ZnO nanoparticles was ascertained by the FTIR spectra. XRD analysis confirmed the impregnation of ZnO nanoparticles and sericin within the PVA matrix. XRD and FESEM of the bionanocomposites provided information about their semicrystalline nature, crystallite size of the particles, and irregular rough surfaces. The TEM confirmed the size of ZnO particles to be in the nanometer range. AFM confirmed the platykurtic nature of the surface while the negative surface skewness shows the predominance of valleys over peaks suggesting for the planar nature of the surface of the bionanocomposites. UV absorption properties of bionanocomposite films were determined by UV absorption spectroscopy. UV absorption increased with increasing amount of ZnO nanoparticles in the nanocomposites. Sericin was found to absorb UV-C radiations between 200-290nm which is mainly due to aromatic amino acids like tryptophan, tyrosine and phenylalanine. The ZnO nanoparticles and sericin protein showed antimicrobial properties as evident from the inhibition zones obtained against Staphylococcus aureus and Escherichia coli. The bionanocomposite was found to be noncytotoxic which was proved by in vitro cytotoxicity test. Microhardness of bionanocomposite films increased with increase in the amount of ZnO nanoparticles in the sericin and PVA matrix.

Genipin-modified gelatin nanocarriers as swelling controlled drug delivery system for in vitro release of cytarabine.

The aim of the present investigation was to design biocompatible gelatin nanoparticles, capable of releasing the cytarabine drug in a controllable way by regulating the extent of swelling of nanoparticles. In order to achieve the proposed objectives, gelatin (Type A, derived from acid cured tissue) was modified by crosslinking with genipin and nanoparticles of crosslinked gelatin were prepared using single water in oil (W/O) emulsion technique. The nanoparticles were characterized by techniques like FTIR, SEM, TEM, particles size analysis, and surface potential measurements. The nanoparticle chemical architecture was found to influence drug-releasing capacity. The influence of experimental conditions such as pH and simulated physiological fluids as the release medium was also investigated on the release profiles of cytarabine. It is possible to fabricate high-performance materials, by designing of controlled size gelatin nanoparticles with good biocompatible properties along with desired drug release profiles.

Designing slow water-releasing alginate nanoreserviors for sustained irrigation in scanty rainfall areas.

In this study, water absorbing Ca(2+) ion cross-linked alginate nanoparticles were prepared and their water holding capacity was assessed. The prepared nanoparticles were characterized by Fourier transform infra red (FTIR) and X-ray diffraction (XRD) spectroscopy, field emission scanning electron microscopy (FESEM), and Zeta potential measurements to gain insights into their structural and morphological features and to see if the nanoparticles carried a charge over them. The swelling experiments were performed for different compositions of prepared nanoparticles at varied pH and temperatures. The capacity of the nanoparticles to retain imbibed water was evaluated by conducting deswelling studies of the pre-swollen nanoparticles. These particles were mixed with soil and soil-pot experiments were conducted. In order to assess the sustained water release potential of nanoparticles in agricultural fields, the seeds were planted in both native and nanoparticle-mixed soil pots, and moisture content of the soil was measured periodically and growth of the plants was observed.

Molecular characterization and phylogenetic relationships among microsporidian isolates infecting silkworm, Bombyx mori using small subunit rRNA (SSU-rRNA) gene sequence analysis.

The life cycle, spore morphology, pathogenicity, tissue specificity, mode of transmission and small subunit rRNA (SSU-rRNA) gene sequence analysis of the five new microsporidian isolates viz., NIWB-11bp, NIWB-12n, NIWB-13md, NIWB-14b and NIWB-15mb identified from the silkworm, Bombyx mori have been studied along with type species, NIK-1s_mys. The life cycle of the microsporidians identified exhibited the sequential developmental cycles that are similar to the general developmental cycle of the genus, Nosema. The spores showed considerable variations in their shape, length and width. The pathogenicity observed was dose-dependent and differed from each of the microsporidian isolates; the NIWB-15mb was found to be more virulent than other isolates. All of the microsporidians were found to infect most of the tissues examined and showed gonadal infection and transovarial transmission in the infected silkworms. SSU-rRNA sequence based phylogenetic tree placed NIWB-14b, NIWB-12n and NIWB-11bp in a separate branch along with other Nosema species and Nosema bombycis; while NIWB-15mb and NIWB-13md together formed another cluster along with other Nosema species. NIK-1s_mys revealed a signature sequence similar to standard type species, N. bombycis, indicating that NIK-1s_mys is similar to N. bombycis. Based on phylogenetic relationships, branch length information based on genetic distance and nucleotide differences, we conclude that the microsporidian isolates identified are distinctly different from the other known species and belonging to the genus, Nosema. This SSU-rRNA gene sequence analysis method is found to be more useful approach in detecting different and closely related microsporidians of this economically important domestic insect.

Magnetically controlled release of cisplatin from superparamagnetic starch nanoparticles.

The present study involves a novel strategy for the preparation of superparamagnetic nanoparticles of crosslinked starch impregnated with homogeneously dispersed nanosized iron oxide. The nanoparticles were loaded with an anticancer drug 'cisplatin' and the drug release kinetics was investigated spectrophotometrically at physiological pH (7.4). The nanoparticles were characterized by Fourier transform infra red (FTIR) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction and magnetization studies. The particle size of magnetic starch nanoparticles was found to lie in the range of 20-90nm. The influence of factors like chemical composition of nanoparticles, pH and temperature of the release media and applied magnetic field was investigated on the release profiles of the drug. The prepared nanoparticles could provide a possible pathway for targeted and controlled delivery of anticancer drugs minimizing side effects and achieving higher efficacy.

Magnetically guided release of ciprofloxacin from superparamagnetic polymer nanocomposites.

Tailored with superparamagnetic properties the magnetic nanocomposites have been thoroughly investigated in recent past because of their potential applications in the fields of biomedicine and bioengineering such as protein detection, magnetic targeted drug carriers, bioseparation, magnetic resonance imaging contrast agents and hyperthermia. Magnetic drug targeting has come up as a safe and effective drug-delivery technology, i.e., with the least amount of magnetic particles a maximum of drug may be easily administered and transported to the site of choice. In the present work novel magnetic drug-targeting carriers consisting of magnetic nanoparticles encapsulated within a smart polymer matrix with potential of controlled drug release is described. To make such magnetic polymeric drug-delivery systems, both the magnetic nanoparticles and antibiotic drug (ciprofloxacin) were incorporated into the hydrogel. The controlled release process and release profiles were investigated as a function of experimental protocols such as percent loading of drug, chemical composition of the nanocomposite, pH of release media and strength of magnetic field on the release profiles. The structure, morphology and compositions of magnetic hydrogel nanocomposites were characterized by FT-IR, TEM, XRD and VSM techniques. It was found that magnetic nanocomposites were biocompatible and superparamagnetic in nature and could be used as a smart drug carrier for controlled and targeted drug delivery.

Magnetically mediated release of ciprofloxacin from polyvinyl alcohol based superparamagnetic nanocomposites.

Polymer nanocomposites exhibiting superparamagnetic behavior have been recognized as a promising tool to achieve targeted drug delivery using external magnetic field for treating complex diseases like cancers and tumors. The present investigation attempts to design a superparamagnetic nanocomposite which could desirably deliver ciprofloxacin drug by application of varying magnetic field. In order to achieve the proposed objectives, a polymer matrix of polyvinyl alcohol-g-polymethyl methacrylate was prepared by free radical polymerization and iron oxide particles were impregnated by in situ precipitation method. The prepared nanocomposites were characterized by techniques like FTIR, electron microscopy (SEM and TEM) and XRD and magnetization studies were performed to ensure superparamagnetic behavior. The antibiotic drug ciprofloxacin was loaded onto the magnetic nanocomposites and the influence of various factors such as percent loading, chemical composition of the nanocomposite, applied magnetic field, pH of the release medium were investigated on the release profiles of the drug. The chemical integrity of the drug and its antibacterial potential were also studied. The dynamics of the release process was also examined mechanistically.

Designing polysaccharide-based antibacterial biomaterials for wound healing applications.

In this study, the development and characterization of novel polymer blends based on chitosan-poly (vinyl alcohol) and physically cross-linked by freeze-thaw method for possible use in a variety of biomedical application is reported. The present investigation deals with designing savlon-loaded blend hydrogels (coined as cryogels) of poly (vinyl alcohol) (PVA) and chitosan by repeated freeze-thaw method and their characterization by SEM and FTIR techniques. The FTIR spectra clearly reveal that savlon-loaded chitosan and PVA blends are bonded together through hydrogen bonding. The SEM analysis suggests that cryogels show a well-defined porous morphology. The prepared cryogels were also investigated for swelling and deswelling behaviors. The results reveal that both the swelling and deswelling behaviors greatly depend on factors like chemical composition of the cryogels, number of freeze-thaw cycles, pH and temperature of the swelling bath. The savlon-loaded blends were also investigated for their in vitro blood compatibility and antibacterial activity.

Association of leaf micro-morphological characters with powdery mildew resistance in field-grown mulberry (Morus spp.) germplasm.

BACKGROUND AND AIMS: Micro-morphological characteristics can influence fungal infectivity. We sought links between micro-morphology and resistance to powdery mildew in mulberry with the intention of assisting selection of disease-resistant lines. METHODOLOGY: Over 3 years and under field conditions, we evaluated 30 lines of mulberry with contrasting susceptibilities to powdery mildew (15 resistant and 15 susceptible). Disease severity was related statistically to stomatal area, stomatal density, stomatal index, upper and lower cuticular thicknesses, leaf thickness and trichome density. PRINCIPAL RESULTS: Differences between lines were significant (P <0.05) for all characters studied. Variation between the resistant and susceptible groups was statistically highly significant (P <0.01) for stomatal index, stomatal area and trichome density. The powdery mildew-resistant group was distinguished by  17.4 % lower stomatal density, 12.5 % smaller stomatal index per unit leaf area, 20.0 % greater trichome density and 18.0 % higher stomatal area compared with the susceptible group. Trichome density was negatively correlated with disease severity index and with the accumulative area under disease progression curves. Stomatal density was positively correlated with both measures of disease severity. Although stomatal area was negatively related to disease severity index (r = -0.28; P <0.05), the correlation was weak. There was no statistically significant relationship between stomatal area and the accumulative area under disease progression curves. The germplasm was partitioned into seven sub-groups based on hierarchical cluster analysis derived from pooled disease severity index scores and three highly significant micro-morphological characters. Eighty per cent of the resistant germplasm accumulated in three cluster components (A1, A2 and B2) characterized by high trichome densities and a high stomatal density and stomatal index. CONCLUSIONS: Resistance to powdery mildew in mulberry is associated with trichome and stomatal features rather than leaf and epidermal thicknesses. Trichome density, stomatal density and stomatal index are shown to be promising markers for screening powdery mildew resistance in breeding programmes.

Investigation on magnetically controlled delivery of doxorubicin from superparamagnetic nanocarriers of gelatin crosslinked with genipin.

Gelatin (Type B) nanoparticles were prepared by a single W/O emulsion technique and characterized by infrared (IR) spectra, transmission electron micrographs (TEM), surface potential measurements and magnetization studies. Whereas the IR spectra clearly confirmed the presence of gelatin, genipin and doxorubicin in the loaded nanoparticles, the transmission electron micrographs (TEM) image depicts smooth surface, spherical shape and non-uniform size of nanoparticles (up to 100 nm). The prepared nanoparticles were loaded with doxorubicin, a well known anticancer drug, and in vitro release dynamics of entrapped drug was investigated as a function of various experimental factors such as percent loading of the drug, chemical architecture of the nanocarriers, and pH, temperature, ionic strength and nature of the release medium in presence and absence of magnetic field. The nanoparticles were also studied for their water sorption capacity. The drug release process was analyzed kinetically using Ficks power law and a correlation was established between the quantity of released drug and swelling of the nanoparticles.

Designing of macroporous biocompatible cryogels of PVA-haemoglobin and their water sorption study.

Macroporous polymeric materials are three-dimensional porous architectures having enormous utility in the areas of biomedical, biotechnological and separation sciences. Thus realizing the crucial role of macroporous polymeric materials in tissue engineering and allied fields the present paper discusses synthesis, characterization, and blood compatibility study of macroporous cryogels of PVA and haemoglobin. Biocompatible spongy and porous hydrogels of polyvinyl alcohol-haemoglobin have been synthesized by repeated freezing-thawing method and characterized by Infrared (FTIR), and ESEM techniques. The FTIR analysis of prepared cryogels indicated that haemoglobin was introduced into the cryogel possibly via hydrogen bonds formed amongst hydroxyl groups and amino groups present in PVA and haemoglobin, respectively. The 'cryogels' were evaluated for their water uptake potentials and influence of various factors such as chemical architecture of the spongy hydrogels, pH and temperature of the swelling bath were investigated on the degree of water sorption by the cryogels. The hydrogels were also swollen in salt solutions and various simulated biological fluids. The effect of drying temperature on its water sorption capacity was also studied. The biocompatibility of the prepared cryogels was judged by in vitro methods of blood-clot formation, percent haemolysis and protein (BSA) adsorption.

An in vitro release study of 5-fluoro-uracil (5-FU) from swellable poly-(2-hydroxyethyl methacrylate) (PHEMA) nanoparticles.

Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. The use of nanoparticles as drug delivery vehicles for anticancer therapeutics has great potential to revolutionize the future of cancer therapy. The present paper concerns both the optimizations of anticancer drug loading and its release from polymeric nanoparticles. The major aim of this study was to design poly (HEMA) nanoparticles as swelling controlled drug release system for anticancer drug. The prepared nanoparticles were characterized by Infra-Red (IR) Spectra, Particle size Analysis, and Scanning Electron Microscopy (SEM). The nanoparticles were loaded with widely used anticancer drug, 5-Fluorouracil, and controlled release of drug was investigated to observe the effects of various parameters such as percent loading of the drug, chemical architecture of the nanocarriers, pH, temperature, and nature of release media on the release profiles. The chemical stability of 5-Fluorouracil (5-FU) was also tested in phosphate buffer saline (PBS) (pH = 7.4) and release was studied in various simulated biological fluids. The prepared nanoparticles could provide a possible pathway for controlled and targeted delivery of anticancer drug, thus causing lower side effects and higher efficacy.

Evaluation of water sorption property and in vitro blood compatibility of poly(2-hydroxyethyl methacrylate) (PHEMA) based semi interpenetrating polymer networks (IPNs).

pH responsive smart biomaterials of gelatin and poly(2-hydroxyethyl methacrylate-co-acrylic acid) were synthesized by redox polymerization and characterized by FTIR, Environmental Scanning Electron Microscopy (ESEM). The prepared environmental responsive biomaterials containing polyelectrolyte segments were assessed for their water sorption potential under varying experimental conditions. The diffusion mechanism of transport of water molecules arising due to solvent-polymer interaction was also analysed to predict the behaviour of continuously relaxing macromolecular chains. The in vitro blood compatibility of the prepared polymeric hydrophilic materials was evaluated by methods such as blood clot formation, platelet adhesion, percent haemolysis and protein-adsorption study on the surface of the prepared biomaterials.

Carboxymethyl cellulose (CMC) based semi-IPNs as carriers for controlled release of ciprofloxacine: an in-vitro dynamic study.

Semi-interpenetrating polymer networks (IPNs) of carboxymethyl cellulose (CMC) and polyacrylic acid were prepared and its potential for controlled release of ciprofloxacine (Cfx) was assessed. The IPNs were characterized by IR spectral analysis and Environmental scanning electron microscopy (ESEM). The entrapped drug was examined for its antibacterial activity and chemical stability. The effects of experimental parameters such as varying chemical composition of the IPNs, percent loading of Cfx, pH and temperature of release medium and presence of salt ions in outer solution were examined on the release profile of the drug. On the basis of Fick's power law equations, the diffusion exponents (n) and diffusion constant (D) were evaluated for different IPNs compositions. From the kinetic parameter data, an attempt was made to resolve the mechanism of the release process of Cfx.

Fibrinogen adsorption onto macroporous polymeric surfaces: correlation with biocompatibility aspects.

The present work focus on the adsorption of fibrinogen (Fgn) on to the semi-interpenetrating polymer networks (IPNs) of polyethylene glycol (PEG) and poly(2-hydroxyethyl methacrylate-co-acrylonitrile) and attempts to correlate the adsorption behaviour of proteins to the blood compatible aspects of the polymeric surfaces. The semi-IPNs were prepared by copolymerizing 2-hydroxyethyl methacrylate and acrylonitrile in the presence of PEG and a crosslinker ethyleneglycol dimethacrylate (EGDMA). The prepared spongy gels were characterized by FTIR and Environmental Scanning Electron Microscopy (ESEM) for structural and morphological analysis. The prepared semi IPNs were studied for their water sorption capacity and the data were utilized to evaluate network parameters such as average molecular weight between crosslinks (M(c)) and crosslink density (q). The adsorption of Fgn was carried out on to the prepared polymeric matrices and static and dynamic aspects of the adsorption process were investigated. The adsorption process was also studied as a function of pH and ionic strength of the protein solution and chemical architecture of the semi IPN. The antithrombogenic properties of the IPN's were also judged and correlated with water sorption and protein adsorption findings.

Dynamics of controlled release of heparin from swellable crosslinked starch microspheres.

The microspheres of crosslinked starch have been prepared and characterized by IR spectral analysis and SEM technique. The prepared microspheres were loaded with an anticoagulant drug 'heparin' and the kinetics of in-vitro release of heparin was investigated spectrophotometrically at physiological pH (7.4) and body temperature (37 degrees C). The influence of percent loading of heparin, chemical architecture of the microspheres and pH of the release medium were examined on the release profiles of the drug. The chemical stability of heparin was tested in phosphate buffer saline (pH 7.4) and the release was also studied in various simulated biological fluids.

Studies on alpha-amylase induced degradation of binary polymeric blends of crosslinked starch and pectin.

A blend matrix of crosslinked starch and pectin was prepared and characterized by infra-red (IR) spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The prepared blends were investigated kinetically for water sorption studies and alpha-amylase induced degradation adopting a gravimetric procedure. Based on the experimental findings, a plausible mechanism including both diffusion and surface enhanced degradation was suggested and degradation profiles were interpreted. The influence of various factors such as chemical architecture of the blend, pH and temperature of alpha-amylase solution were examined for the swelling and degradation kinetics of crosslinked starch-pectin blends. The effect of concentration of enzyme solution was also studied on the degradation profile of the blends. A correlation was established between the extent of degradation and water imbibing capacity of the degrading blends.