Microwave-assisted synthesis of cellulose/zinc-sulfate­calcium-phosphate (ZSCAP) nanocomposites for biomedical applications.

In this study, zinc-sulfate-calcium-phosphate (ZSCAP) ceramics was prepared by calcination in the presence of microwave irradiation using precursors ZnSO4:ZnO:CaO:P2O5 in a ratio of 15:30:30:25 (by weight). The calcined ZSCAP ceramics was mixed with microcrystalline cellulose and it was further heated by microwave radiation for the preparation of cellulose/ZSCAP nanocomposites. It was found that microwave heating time played an important role in the crystalline phase of synthesized nanocomposites of cellulose/ZSCAP. Well-crystalline phases of calcium phosphate, zinc oxide and zinc sulfate were observed in the nanocomposites at 20 min of microwave heating time. Fourier transformed infrared spectroscopy (FTIR) and Raman spectroscopy confirmed that the obtained products were of cellulose/ZSCAP nanocomposites. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images indicated that reinforced ZSCAP nanostructures were embedded into cellulose matrix. Energy dispersive X-ray spectroscopy (EDS) further supported the presence of Zn, S, Ca and P in cellulose/ZSCAP nanocomposites. The thermal behavior of the products was studied using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The prepared nanocomposites showed antibacterial activity against Staphylococcus aureus and Escherichia coli. In vitro cytotoxicity assay revealed that the prepared nanocomposites had no influence on proliferation of MG-63 cells. This rapid microwave-assisted method is simple, fast and suitable for the production of cellulose/ZSCAP nanocomposites, which finds its biomedical applications in tissue engineering and bone repair.

Studies on the synthesis, spectral, optical and thermal properties of l-Valine Zinc Sulphate: an organic inorganic hybrid nonlinear optical crystal.

Nonlinear optical (NLO) organic inorganic hybrid l-Valine Zinc Sulphate (LVZS) was synthesized and single crystals were obtained from saturated aqueous solution by slow evaporation method at 36°C using a constant temperature bath (CTB) with an accuracy of ±0.01°C. This crystal is reported with its characterization by single crystal and powder XRD, FTIR, UV-Vis-NIR, TG/DTA analysis and SHG test. Single crystal XRD study reveals that LVZS crystallizes in monoclinic system with the lattice constants a=9.969(3) Å, b=7.238(3) Å, c=24.334(9) Å and cell volume is 1736.00Å(3). Sharp peaks observed in powder X-ray diffraction studies confirm the high degree of crystallinity of grown crystal. The incorporation of sulphate ion with l-valine is confirmed by FTIR spectrum in LVZS crystal(.) A remarkable increase in optical transparency has been observed in LVZS when compared to l-valine and zinc sulphate heptahydrate Thermal properties of LVZS have been reported by using TG/DTA analysis. Kurtz powder second harmonic generation (SHG) test confirms NLO property of the crystal and SHG efficiency of LVZS was found to be 1.34 times more than pure l-valine.