@misc{IvanovKurniawanTsakovaetal., author = {Ivanov, Svetlozar D. and Kurniawan, Fredy and Tsakova, Vessela T. and Mirsky, Vladimir M.}, title = {Automated layer-by-layer deposition of polyelectrolytes in flow mode}, series = {Macromolecular Materials and Engineering}, volume = {294}, journal = {Macromolecular Materials and Engineering}, number = {6-7}, issn = {1439-2054}, doi = {10.1002/mame.200800376}, pages = {441 -- 444}, abstract = {Multilayer structures of conducting polymers were fabricated by a simply automated approach in flow mode. Polyaniline and poly(styrene sulfonate) were used as a model system, allowing a fast electrochemical and spectroscopic determination of the amount of deposited material. The technology was applied for layer-by-layer deposition of up to 100 bilayers. The results demonstrate a well reproducible and almost constant amount of the adsorbed polymer at each deposition cycle. The method can be applied for deposition of other conducting or non-conducting polymers, biological macromolecules and composites of polyelectrolytes and nanoparticles.}, language = {en} } @misc{HodzhaogluKurniawanMirskyetal., author = {Hodzhaoglu, Feyzim and Kurniawan, Fredy and Mirsky, Vladimir M. and Nanev, Christo}, title = {Gold nanoparticles induce protein crystallization}, series = {Crystal Research and Technology}, volume = {43}, journal = {Crystal Research and Technology}, number = {6}, issn = {1521-4079}, doi = {10.1002/crat.200811125}, pages = {588 -- 593}, abstract = {Nucleation of protein crystals by gold nanoparticles was observed. Lysozyme and ferritin were used as model proteins. The effect was established with uncoated gold nanoparticles and with gold nanoparticles coated by 16-mercaptodecanoic acid.}, language = {en} } @misc{KurniawanTsakovaMirsky, author = {Kurniawan, Fredy and Tsakova, Vessela T. and Mirsky, Vladimir M.}, title = {Analytical applications of electrodes modified by gold nanoparticles: dopamine detection}, series = {Journal of Nanoscience and Nanotechnology}, volume = {9}, journal = {Journal of Nanoscience and Nanotechnology}, number = {4}, issn = {1533-4880}, doi = {10.1166/jnn.2009.SE13}, pages = {2407 -- 2412}, abstract = {Dopamine oxidation was studied on modified gold (nano-Au) electrodes obtained by Layer-by-Layer deposition of gold nanoparticles and polyacrylic acid. A gradual loss of electrochemical activity for the dopamine oxidation reaction is observed at pH 7. Simultaneous SPR spectroscopy and cyclic voltammetry indicate the formation of an adsorbed layer on the electrode surface at this pH value. Investigations, performed through electrochemical and SPR measurements at pH 4, give evidence for a reversible process. At this pH value both dopamine oxidation and reduction current peaks show linear dependence on the dopamine concentration and may be used for analytical applications. The use of the nano-Au electrode allows resolving the peaks corresponding to ascorbic acid and to dopamine oxidation by 240 mV thus providing a high selectively for dopamine detection in the presence of ascorbic acid. The detection limit of this electrode for dopamine is below 4 microM in the presence of 1 mM ascorbic acid. The sensitivity normalized to the macroscopic electrode surface is about 10 mA cm(-2) mM(-1) at sweep rate of 10 V/s.}, language = {en} } @misc{KurniawanTsakovaMirsky, author = {Kurniawan, Fredy and Tsakova, Vessela T. and Mirsky, Vladimir M.}, title = {Gold nanoparticles in non-enzymatic electrochemical detection of sugars}, series = {Electroanalysis}, volume = {18}, journal = {Electroanalysis}, number = {19-20}, issn = {1521-4109}, doi = {10.1002/elan.200603607}, pages = {1937 -- 1942}, abstract = {A nonenzymatic electrochemical sensor for detection of sugars was prepared by layer-by-layer deposition of gold nanoparticles on thin gold electrodes. The deposition was optimized by using of surface plasmon resonance. Voltammetric investigation and impedance spectroscopy of the sensor was performed. Electrical currents caused by glucose on bare gold electrodes and on gold electrodes coated by immobilized gold nanoparticles were compared. The electrodes with nanoparticles display much higher current of glucose oxidation. The oxidation becomes blocked when the swept electrode potential exceeded +0.25 V, during the back scan an oxidation peak is observed again but at less positive potential. The magnitudes of these current peaks are linearly dependent on the glucose concentration; this dependence can be used as calibration for analytical applications. The limit of detection for glucose is below 0.5 mM, the sensitivity (normalized to the macroscopic electrode surface) is about 160 μA cm-2 mM-1. The sensor response is linear till at least 8 mM of glucose concentration.}, language = {en} }