Browsing by Author "Fleischer, H.N.A."
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Item Crystallization of linde type a nanomaterials at two temperatures exhibit differential inhibition of HeLa cervical cancer cells in vitro(Trans Tech Publications Ltd, 2016) Tiburu, E.K.; Fleischer, H.N.A.; Aidoo, E.O.; Salifu, A.A.; Asimeng, B.O.; Zhou, H.This work reports evidence of the synthesis of zeolite A at two different temperatures (60 °C and 105 °C) from kaolin. XRD spectral analysis revealed percent crystallinity of 74 ± 2 and 71 ± 3 in LTA60 and LTA105 respectively. The average crystallize size of LTA60 and LTA105 was also estimated using Scherrer's equation to be 57 nm. FTIR analysis showed signature peaks characteristics of zeolite A in the two materials, except the appearance of absorbance peak at 2380 cm-1 in the LTA60 spectrum which was not observed in LTA105. Nitrogen porosity measurements of LTA60 and LTA105 gave the following parameters: average pore width of 2.45 and 1.01 nm respectively for LTA60 and LTA105, surface areas of 19.18 and 8.00 m2/g and pore volume of 0.012 and 0.002 cm3/g in that order. The influence of the materials on HeLa cancer cell growth was also investigated and the results showed differential inhibitory effects with LTA60 revealing pronounced inhibitory effects compared to LTA105 after 72 hours of cell incubation. This studies highlighted the importance of crystallization conditions that could influence the physicochemical parameters including structure, porosity, size, and morphology of zeolite materials on cell activity. The work also provided unique opportunities for utilizing natural deposits of kaolin globally to fabricate biomimetic materials for various biological applications. © 2016 Trans Tech Publications, Switzerland.Item Investigating the Influence of Temperature on the Kaolinite-Base Synthesis of Zeolite and Urease Immobilization for the Potential Fabrication of Electrochemical Urea(Sensors (Switzerland), 2017-08) Anderson, D.E.; Balapangu, S.; Fleischer, H.N.A.; Viade, R.A.; Krampa, F.D.; Kanyong, P.; Awandare, G.A.; Tiburu, E.K.Temperature-dependent zeolite synthesis has revealed a unique surface morphology, surface area and pore size which influence the immobilization of urease on gold electrode supports for biosensor fabrication. XRD characterization has identified zeolite X (Na) at all crystallization temperatures tested. However, N2 adsorption and desorption results showed a pore size and pore volume of zeolite X (Na) 60 °C, zeolite X (Na) 70 °C and zeolite X (Na) 90 °C to range from 1.92 nm to 2.45 nm and 0.012 cm3/g to 0.061 cm3/g, respectively, with no significant differences. The specific surface area of zeolite X (Na) at 60, 70 and 90 °C was 64 m2/g, 67 m2/g and 113 m2/g, respectively. The pore size, specific surface area and pore volumes of zeolite X (Na) 80 °C and zeolite X (Na) 100 °C were dramatically increased to 4.21 nm, 295 m2/g, 0.762 cm3/g and 4.92 nm, 389 m2/g, 0.837 cm3/g, in that order. The analytical performance of adsorbed urease on zeolite X (Na) surface was also investigated using cyclic voltammetry measurements, and the results showed distinct cathodic and anodic peaks by zeolite X (Na) 80 °C and zeolite X (Na) 100 °C. These zeolites’ molar conductance was measured as a function of urea concentration and gave an average polynomial regression fit of 0.948. The findings in this study suggest that certain physicochemical properties, such as crystallization temperature and pH, are critical parameters for improving the morphological properties of zeolites synthesized from natural sources for various biomedical applications.