Kangkana Sarkar

Detoxification of Hg(II) from aqueous and enzyme media: Pristine vs. tailored calcium alginate hydrogels.

Calcium alginate (CA) hydrogels were tailored using phenolic compounds (PC) like, thymol, morin, catechin, hesperidin, during their preparation. The PC incorporated gels show modified surface features as indicated by scanning electron microscopic images (SEM). The rheological studies show that excepting the hesperidin incorporated gels all the other kinds including calcium alginate pristine have similar mechanical strength. The hesperidine incorporated CA gels had the maximum capacity to adsorb Hg. The Freundlich adsorption isotherms show higher values of adsorption capacity for all PC incorporated CA beads than the pristine CA (PCA). The hesperidin incorporated CA gels were found to show the best adsorption condition at neutral pH and an optimum contact time of 2.5h at 25°C. Considering the possibility of ingested Hg detoxification from human alimentary tract, the hesperidin and morin incorporated CA beads were further modified through incorporation of cod liver oil as the digestion time of fat in stomach is higher. In vitro uptake capacities of Hg in pepsin and pancreatin containing enzyme media were studied with hesperidin and morin incorporated beads and their corresponding fat incorporated beads also. In the pepsin medium, there was no uptake by hesperidin and fat-hesperidin incorporated beads, which is possibly due to the higher acidity of the medium. But in pancreatin medium Hg was taken up by both kinds of beads. Morin and morin-fat incorporated beads were efficient to uptake Hg from both the pepsin and pancreatin medium. The tailored CA beads may therefore serve as efficient scaffolds to rescue Hg ingested individuals.

Enhanced anion sensing by γ-irradiated polyphenol capped iron oxide nanoparticles

Abstract A novel method was designed for the synthesis of polyphenol capped amorphous iron oxide nanoparticles (ION) using an agro waste (peanut skin). The synthesized nanoparticles were characterized by absorption spectroscopy, TEM, SEM, IR, Raman and XRD. An increased rate of formation of the nanoparticles is observed upon low dose gamma irradiation. ION shows specific spectral features with perchlorate anion even in presence of other anions selected for the anion sensing study. The nanoparticles formed in presence of irradiation was found even more sensitive to lower concentration of perchlorate owing to its finely dispersed nature and increased surface area.

On the design of Ag–morin nanocomposite to modify calcium alginate gel: framing out a novel sodium ion trap

The present work describes the design of a Ag–morin nanocomposite and its subsequent incorporation in calcium alginate gels which have the unique property to uptake and release sodium ions. The nanocomposite reported here is the first of its kind and is capable of modifying the calcium alginate gels both physically and chemically. The corrugated surface morphology of calcium alginate becomes modified and becomes smoother upon incorporation of the nanocomposite. Rheological studies reveal an increased viscoelastic nature upon modification of calcium alginate gels which are developing as wound dressing materials. The modified gel will be supposedly a better dressing material as it can also handle saline solution which in turn is a prerequisite for wound healing treatment.

Incorporation of no-carrier added 200,203Pb and 200,201,202Tl in calcium alginate and hesperidin incorporated calcium alginate beads

When radioisotopes are injected to human body, instantly free radicals are generated due to the interaction of ionizing radiation with water and fluids present in the body. The vehicle carrying radionuclides into human body should therefore be designed in a way which could also eliminate or reduce such possibilities. For the first time we have used free radical scavenger hesperidin, a polyphenolic compound having a benzo-γ-pyrone with a benzene ring moiety for extraction of no-carrier added (NCA) 200,203Pb and 200,201,202Tl. We have modified CA beads by incorporation of a polyphenol (hesperidin) (CA-Hes). This tailor made beads were characterized and tested for their efficacy towards extraction of no-carrier-added lead and thallium radioisotopes from 40MeV α particle irradiated Hg2Cl2 target.

Separation of no-carrier-added 203Pb, a surrogate radioisotope, from proton irradiated natTl2CO3 target using calcium alginate hydrogel beads

Abstract 203Pb is a promising radioisotope in the field of medical science as an imaging surrogate of 212Pb. In the present investigation 203Pb was produced by proton irradiation of natural Tl2CO3 target and was separated from the bulk Tl target using calcium alginate (CA) hydrogel beads with a high separation factor (3.8×104 at 10−3 M HNO3). During the separation process 203Pb was encapsulated in CA beads and desorption of the radioisotope could only be achieved in 1M HNO3. Possibility of Tl uptake was also checked in Fe doped CA (Fe-CA) beads after oxidation of Tl(I) to Tl(III) by sodium bismuthate. No significant uptake of Tl(III) was noticed in the Fe-CA beads. The matrix is therefore suitable for isolation of 203Pb from the target as well as its storage in the bead for therapeutic as well as diagnostic purpose.

Radiometric analysis of isotherms and thermodynamic parameters for cadmium(II) adsorption from aqueous medium by calcium alginate beads

Studies on the extraction behavior and immobilization of cadmium by greener reagents have important bearings in today’s science. No-carrier-added (NCA), 109Cd radionuclide is a potential candidate towards radiopharmaceutical studies for both in vivo and in vitro applications and is also used in industrial and environmental studies. Herein, we have studied the adsorption and desorption characteristics of cadmium in both NCA and bulk concentrations into calcium alginate using radiochemical method. Various isotherms like Langmuir, Freundlich, Temkin and Dubinin–Radushkevich have been studied and compared to match the adsorption phenomenon. A spontaneous endothermic physisorption process is expected from thermodynamic parameters.