Browsing by Author "Kibar, G."
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Item Open Access Newly designed silver coated-magnetic, monodisperse polymeric microbeads as SERS substrate for low-level detection of amoxicillin(Elsevier, 2016-09) Kibar, G.; Topal, A. E.; Dana, A.; Tuncel, A.We report the preparation of silver-coated magnetic polymethacrylate core-shell nanoparticles for use in surface-enhanced Raman scattering based drug detection. Monodisperse porous poly (mono-2-(methacryloyloxy)ethyl succinate-co-glycerol dimethacrylate), poly (MMES-co-GDMA) microbeads of ca. 5 μm diameter were first synthesized through a multistage microsuspension polymerization technique to serve as a carboxyl-bearing core region. Microspheres were subsequently magnetized by the co-precipitation of ferric ions, aminated through the surface hydroxyl groups and decorated with Au nanoparticles via electrostatic attraction. An Ag shell was then formed on top of the Au layer through a seed-mediated growth process, resulting in micron-sized monodisperse microbeads that exhibit Raman enhancement effects due to the roughness of the Ag surface layer. The core-shell microspheres were used as a new substrate for the detection of amoxicillin at trace concentrations up to 10-8 M by SERS. The proposed SERS platform can be evaluated as a useful tool for the follow-up amoxicillin pollution and low-level detection of amoxicillin in aqueous media.Item Open Access Single, binary and successive patterning of charged nanoparticles by electrophoretic deposition(Springer, 2021-11-19) Sopubekova, Eliza; Kibar, G.; Yegan Erdem, EmineDeposition of nanoparticles on a substrate in a controlled manner leads to the formation of multifunctional surfaces and therefore devices. Electrostatic forces can be utilized to manipulate different types of materials such as magnetic, insulating, conducting, semiconducting, organic and inorganic, without altering the chemistry of the surface. However, simultaneous and successive electrophoretic deposition (EPD) methods are not fully utilized for nanoparticles with different characteristics. In this work, electrostatic forces are applied to direct and position charged nanoparticles suspended in aqueous dispersions on desired areas of the surface. Assemblies of particles are obtained by electrostatic attraction generated by gold electrodes of sizes from 500 nm to 50 µm that are fabricated by thermal evaporation. Different types of charged nanoparticles were simultaneously attracted towards different locations of the surface by means of EPD; as a result, alternating nanoparticle patterns and particle deposition on the same designated areas for forming composite areas are obtained. Assemblies formed from positively charged silver nanoparticles and negatively charged fluorescent latex and silica nanoparticles are demonstrated. The position of metallic-, polymeric- and inorganic-based nanoparticles is controlled by the design of electrode geometry.