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    Reversible and easy post-crosslinking method for developing a surface ion-imprinted hypercrosslinked monolith for specific Cd(II) ion removal from aqueous solutions
    (Royal Soc Chemistry, 2016) Corman, Mehmet Emin; Armutcu, Canan; Uzun, Lokman; Say, Ridvan; Denizli, Adil
    In this study, a new surface imprinting technique for preparing a hypercrosslinked monolith to remove Cd(II) ions out from aqueous solutions was proposed. The monoliths were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermal gravimetrical analysis, surface area measurements and elemental analysis. The reversible nature of the hypercrosslinking process was proved by repeated crosslinking and denaturation cycles by using ferric ions as an oxidant and urea as a reductant, respectively meanwhile performing surface area measurements for both situations to demonstrate the variation in the surface porosity. The multipoint BET surface areas of poly(HEMA), surface ion imprinted (Cd-SII-HM) and non-imprinted (NI-HM) monoliths were determined as 269.1 m(2) g(-1), 79.1 m(2) g(-1), and 67.4 m(2) g(-1), respectively. By breaking hypercrosslinks, the micropore volume decreased from 39.7 mm3 g-1 to 11.8 mm(3) g(-1) while the cumulative pore volume decreased from 30.7 mm(3) g(-1) to 9.1 mm(3) g(-1) during urea treatment. At the first step, the affecting factors such as initial Cd(II) ion concentrations, pH and adsorption time were optimized. Then, the selectivity of the Cd-SII-HM for Cd(II) against other metal ions was evaluated not only from singular solutions but also from triple and quadruple solutions, which included Pb(II), Zn(II) and Hg(II) ions as competitors. The relative selectivity coefficients were calculated as 3.28, 15.61 and 58.55 for Cd(II)/Zn(II), Cd(II)/Pb(II) and Cd(II)/Hg(II) pairs. The results obtained indicated that the developed reversible and easy post-crosslinking method is quite applicable for producing the surface ion-imprinted polymers with high selectivity for the template ions [Cd(II)] regarding the potential competitor ions [Zn(II), Pb(II) and Hg(II)].
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    Öğe
    Self-oriented nanoparticles for site-selective immunoglobulin G recognition via epitope imprinting approach
    (Elsevier, 2014) Corman, Mehmet Emin; Armutcu, Canan; Uzun, Lokman; Say, Ridvan; Denizli, Adil
    Molecular imprinting is a polymerization technique that provides synthetic analogs for template molecules. Molecularly imprinted polymers (MIPs) have gained much attention due to their unique properties such as selectivity and specificity for target molecules. In this study, we focused on the development of polymeric materials with molecular recognition ability, so molecular imprinting was combined with miniemulsion polymerization to synthesize self-orienting nanoparticles through the use of an epitope imprinting approach. Thus, L-lysine imprinted nanoparticles (LMIP) were synthesized via miniemulsion polymerization technique. Immunoglobulin G (IgG) was then bound to the cavities that specifically formed for L-lysine molecules that are typically found at the C-terminus of the Fc region of antibody molecules. The resulting nanoparticles makes it possible to minimize the nonspecific interaction between monomer and template molecules. In addition, the orientation of the entire IgG molecule was controlled, and random imprinting of the IgG was prevented. The optimum conditions were determined for IgG recognition using the imprinted nanoparticles. The selectivity of the nanoparticles against IgG molecules was also evaluated using albumin and hemoglobin as competitor molecules. In order to show the self-orientation capability of imprinted nanoparticles, human serum albumin (HSA) adsorption onto both the plain nanoparticles and immobilized nanoparticles by anti-human serum albumin antibody (anti-HSA antibody) was also carried out. Due to anti-HSA antibody immobilization on the imprinted nanoparticles, the adsorption capability of nanoparticles against HSA molecules vigorously enhanced. It is proved that the oriented immobilization of antibodies was appropriately succeeded. (C) 2014 Elsevier B.V. All rights reserved.