@misc{MirskyHirschPiletskyetal., author = {Mirsky, Vladimir M. and Hirsch, Thomas and Piletsky, Sergey A. and Wolfbeis, Otto S.}, title = {A spreader-bar approach to molecular architecture: formation of stable artificial chemoreceptors}, series = {Angewandte Chemie International Edition}, volume = {38}, journal = {Angewandte Chemie International Edition}, number = {8}, issn = {1521-3773}, doi = {10.1002/(SICI)1521-3773(19990419)38:8<1108::AID-ANIE1108>3.0.CO;2-C}, pages = {1108 -- 1110}, abstract = {The destructive influence of lateral diffusion on nanostructured monolayers can be prevented by using the spreader-bar technique. This approach allows the formation of stable artificial receptors for barbituric acid by lateral structuring of a dodecanethiol monolayer with molecular spreader-bars from thiobarbituric acid without chemical polymerization (see schematic representation). The new technique may have applications in chemosensors, affinity chromatography, stereoselective catalysis, and molecular electronics.}, language = {en} } @misc{RieplMirskyNovotnyetal., author = {Riepl, Michael and Mirsky, Vladimir M. and Novotny, Ivan and Tvarozek, Vladimir and Rehacek, Vlastimil and Wolfbeis, Otto S.}, title = {Optimization of capacitive affinity sensors: drift suppression and signal amplification}, series = {Analytica Chimica Acta}, volume = {392}, journal = {Analytica Chimica Acta}, number = {1}, issn = {0003-2670}, doi = {10.1016/S0003-2670(99)00195-6}, pages = {77 -- 84}, abstract = {The detection limit of capacitive affinity sensors based on the gold-alkanethiol system can be improved by optimization of sensor preparation and by signal amplification. The dissociation of the gold-sulfur binding is often a critical point leading to operative errors of such sensors. The stability of self-assembled monolayers prepared with different thiols on gold electrodes in aqueous and organic solvents was studied by the capacitive technique. The results show that monolayers made of 16-mercaptohexadecanoic acid are stable in aqueous solution and can be hardly extracted from a gold surface by ethanol, methanol, or dioxane, while a considerable damage of self-assembled monolayers was observed due to incubation in chloroform or dimethylformamide. In contrast, self-assembled monolayers made from short-chain disulfides or thiols (such as 3,3′-dithio-bis(propionic acid N-hydroxysuccinimide ester) or 11-mercaptoundecanoic acid) displayed a poor stability in aqueous phase. Capacitive affinity sensors based on these short-chain thiols showed a considerable drift of the signal. The use of long-chain thiols resulted in a stable signal; it was applied to compare capacitive effects due to immobilization of different biological molecules and for preparation of different biosensors. The response of capacitive biosensors can be amplified by formation of a sandwich structure. This principle was illustrated by subsequent adsorption of polyclonal anti-HSA after binding of HSA with a sensor for HSA based on monoclonal antibodies.}, language = {en} } @misc{RieplMirskyWolfbeis, author = {Riepl, Michael and Mirsky, Vladimir M. and Wolfbeis, Otto S.}, title = {Electrical control of alkanethiols self-assembly on a gold surface as an approach for preparation of microelectrode arrays}, series = {Microchimica Acta}, volume = {131}, journal = {Microchimica Acta}, number = {1}, issn = {0026-3672}, doi = {10.1007/s006040050006}, pages = {29 -- 34}, abstract = {It is shown by capacitive monitoring that the self-assembly of alkanethiols on gold electrodes and desorption of these self-assembled monolayers from the electrodes are controlled by the electrode potential. At neutral pH, chemical adsorption of alkanethiols was observed at an electrode potential of +300 mV vs SCE, but only physical adsorption was detected when the electrode potential was -1400 mV vs SCE. At electrode potentials between these values (-300 mV, -600 mV), chemical adsorption of alkanethiols occurred, but the alkanethiol monolayers were not stable in the absence of the alkanethiol in the bulk solution and were desorbed from the gold electrode. The desorption rate was higher at more negative electrode potentials. These results can be used in designing methods for electrically addressable immobilization of different receptors on (micro)electrode arrays. This has been demonstrated by deposition of two different types of alkanethiols onto a two-electrode array.}, language = {en} } @misc{RehacekNovotnyTvarozeketal., author = {Rehacek, Vlastimil and Novotny, Ivan and Tvarozek, Vladimir and Riepl, Michael and Hirsch, T. and Mass, Markus and Schweiss, R. and Mirsky, Vladimir M. and Wolfbeis, Otto S.}, title = {Capacitive detection in thin film chemical sensors and biosensors}, series = {Advanced Semiconductor Devices and Microsystems}, journal = {Advanced Semiconductor Devices and Microsystems}, editor = {Breza, Jura and Donoval, Daniel}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {0-7803-4909-1}, pages = {255 -- 258}, abstract = {Thin film electrode chips on silicon substrate have been realized and utilized in development of different chemo- and biosensors. These affinity sensors are based on capacitive transducing and their general structure is thin film Au/alkanethiol/receptor. Several applications of thin film gold electrodes in capacitive sensors are presented.}, language = {en} } @misc{SchweissMirskyWolfbeis, author = {Schweiß, R{\"u}diger and Mirsky, Vladimir M. and Wolfbeis, Otto S.}, title = {Capacitive study of self-assembled alkylthiol monolayers: surface charge effects and kinetics of surfactants adsorption}, series = {Materials Science Forum}, volume = {287-288}, journal = {Materials Science Forum}, issn = {1662-9752}, doi = {10.4028/www.scientific.net/MSF.287-288.427}, pages = {427 -- 430}, language = {en} } @misc{MirskyRieplKrauseetal., author = {Mirsky, Vladimir M. and Riepl, Michael and Krause, Christian and Novotny, Ivan and Splonskowski, Markus and Rehacek, Vlastimil and Tvarozek, Vladimir and Hummel, Helmut and Wolfbeis, Otto S.}, title = {Thin film electrodes for capacitive chemo- and biosensors: an optimization of the electrodes geometry}, series = {Materials Science Forum}, volume = {287-288}, journal = {Materials Science Forum}, issn = {1662-9752}, doi = {10.4028/www.scientific.net/MSF.287-288.423}, pages = {423 -- 426}, language = {en} } @misc{AndoSwartPringsheimetal., author = {Ando, Masanori and Swart, Claudia and Pringsheim, Erika and Mirsky, Vladimir M. and Wolfbeis, Otto S.}, title = {Optical ozone detection by use of polyaniline film}, series = {Solid State Ionics}, volume = {152-153}, journal = {Solid State Ionics}, issn = {0167-2738}, doi = {10.1016/S0167-2738(02)00338-7}, pages = {819 -- 822}, abstract = {We report on the optical ozone sensitivity of a polyaniline (PANI) film prepared on the inner wall of a polystyrene cuvette by chemical oxidation of aniline from aqueous solution. The PANI film showed changes of optical absorbance in the presence of 50-100 ppm ozone in air at room temperature. The absorbance change was largest at wavelengths in the range of 500-800 nm. The absorbance changes brought about by ozone was partially reversible after removal of ozone from the atmosphere. These results suggest that PANI is a potential material for optical ozone detection.}, language = {en} } @misc{PanasyukDelaneyMirskyWolfbeis, author = {Panasyuk-Delaney, Tanya and Mirsky, Vladimir M. and Wolfbeis, Otto S.}, title = {Capacitive creatinine sensor based on molecularly imprinted polymer}, series = {Electroanalysis}, volume = {14}, journal = {Electroanalysis}, number = {3}, issn = {1521-4109}, doi = {10.1002/1521-4109(200202)14:3<221::AID-ELAN221>3.0.CO;2-Y}, pages = {221 -- 224}, abstract = {The first reversible chemosensor to creatinine based on artificial chemoreceptors is described. The receptor layer was prepared by molecularly imprinted photopolymerization of acrylamidomethylpropanesulfonic acid and methylenediacrylamide. The polymer layer was grafted onto the surface of gold electrodes coated with an alkanethiol monolayer. Creatinine binding was detected by a decrease in the electrode capacitance. The sensor response is reversible and highly selective: no response to addition of sodium chloride, creatine, urea or glucose were observed. The detection limit for creatinine is 10 μM which is optimal for medical applications.}, language = {en} } @misc{MirskyVasjariNovotnyetal., author = {Mirsky, Vladimir M. and Vasjari, Majlinda and Novotny, Ivan and Rehacek, Vlastimil and Tvarozek, Vladimir and Wolfbeis, Otto S.}, title = {Self-assembled monolayers as selective filters for chemical sensors}, series = {Nanotechnology}, volume = {13}, journal = {Nanotechnology}, number = {2}, issn = {0957-4484}, pages = {175 -- 178}, abstract = {The lateral electrical conductivity of gold layers with thickness in the nanometre range was found to decrease due to adsorption of mercury, water, iodine and sulphuric compounds onto the gold surface. A self-assembled monolayer of hexadecanethiol, deposited on the gold surface, blocked the effects of water and volatile sulphuric compounds on the lateral conductivity of the gold layers, but does not block the effects of iodine and mercury. The results indicate a selective permeability of hexadecanethiol monolayers for mercury vapour, thus providing a method for development of ultrathin filters for chemical sensors.}, language = {en} } @inproceedings{WuLinMirskyetal., author = {Wu, Meng and Lin, Zhihong and Mirsky, Vladimir M. and Wolfbeis, Otto S.}, title = {Detection of DNA hybridization with surface plasmon resonance biosensor: comparison of immobilization of oligonucleotides by ssDNA and dsDNA}, series = {Proceedings, International Conference on Sensor Technology (ISTC 2001), 10 - 12 October 2001, Wuhan, China}, booktitle = {Proceedings, International Conference on Sensor Technology (ISTC 2001), 10 - 12 October 2001, Wuhan, China}, editor = {Zhou, Yikai}, publisher = {SPIE}, address = {Bellingham, Wash.}, isbn = {0-8194-4119-8}, doi = {10.1117/12.440180}, pages = {23 -- 26}, abstract = {In this research, a surface-plasmon resonance biosensor for nucleic acid detection was constructed, optimized and characterized. The kinetic response on hybridization was also studied. The biosensor was use as a platform for the study of the surface coverage control by single-strand or double-strand oligonucleotide immobilization. The dsDNA immobilization and offers a new way to surface coverage control for the nucleic acid biosensor construction.}, language = {en} } @misc{MirskyPanasyukDelaneyWolfbeis, author = {Mirsky, Vladimir M. and Panasyuk-Delaney, Tanya and Wolfbeis, Otto S.}, title = {Chemical sensors based on ultrathin membranes from molecularly imprinted polymers}, series = {Membrane \& cell biology}, volume = {18}, journal = {Membrane \& cell biology}, number = {6}, pages = {496 -- 501}, language = {en} } @inproceedings{LinWuRenetal., author = {Lin, Zhihong and Wu, Meng and Ren, Shu and Arbter, Michaela and Boehmer, Martin and Mirsky, Vladimir M. and Wolfbeis, Otto S.}, title = {Study of single and dual NIR fluorescently labeled nucleic acid conjugates for nucleic acid detection}, series = {Proceedings, International Conference on Sensor Technology (ISTC 2001), 10 - 12 October 2001, Wuhan, China}, booktitle = {Proceedings, International Conference on Sensor Technology (ISTC 2001), 10 - 12 October 2001, Wuhan, China}, editor = {Zhou, Yikai}, publisher = {SPIE}, address = {Bellingham, Wash.}, isbn = {0-8194-4119-8}, doi = {10.1117/12.440165}, pages = {111 -- 114}, abstract = {In this research, a near-IR fluorescent labeled nucleic acid conjugate for the nucleic acid detection was synthesized, and characterized preliminarily for the detection of the nucleic acid. Th conjugate combines the molecular recognition properties of the oligonucleotides with the near-IR fluorescence label PR646. Both single- and dual- labeled conjugates were studied for their hybridization with the complementary nucleic acid. The dual labeled conjugate has indicated that the self-quenching effect exists in ssDNA form while the fluorescence increases greatly after hybridization with the complementary nucleic acids. The time-resolved fluorescence was also studied.}, language = {en} } @misc{BajariLindstedtRiepletal., author = {Bajari, Tarek M. and Lindstedt, Ken A. and Riepl, Michael and Mirsky, Vladimir M. and Nimpf, Johannes and Wolfbeis, Otto S. and Dresel, Hans A. and Bautz, Ekkehard K. F. and Schneider, Wolfgang Johann}, title = {A minimal binding domain of the low density lipoprotein receptor gene family}, series = {Biological Chemistry}, volume = {379}, journal = {Biological Chemistry}, number = {8-9}, issn = {1437-4315}, doi = {10.1515/bchm.1998.379.8-9.1053}, pages = {1053 -- 1062}, language = {en} } @inproceedings{MirskyRieplMassetal., author = {Mirsky, Vladimir M. and Riepl, Michael and Mass, Markus and Hirsch, T. and Schweiss, R. and Wolfbeis, Otto S.}, title = {Capacitive detection of analyte binding in thin film chemo- and biosensors}, series = {Solid State Chemical and Biochemical Sensors}, booktitle = {Solid State Chemical and Biochemical Sensors}, editor = {Vincenzini, Pietro and Dori, L.}, publisher = {Techna}, address = {Faenza}, isbn = {88-86538-27-8}, pages = {441 -- 448}, language = {en} } @misc{MirskyMassKrauseetal., author = {Mirsky, Vladimir M. and Mass, Markus and Krause, Christian and Wolfbeis, Otto S.}, title = {Capacitive approach to determine phospholipase A2 activity towards artificial and natural substrates}, series = {Analytical Chemistry}, volume = {70}, journal = {Analytical Chemistry}, number = {17}, issn = {0003-2700}, doi = {10.1021/ac980102w}, pages = {3674 -- 3678}, abstract = {A capacitive approach has been employed to develop a novel method to determine phospholipase activity. The sensing electrodes have a structure like Au/S(CH₂)₁₇CH₃/substrate/electrolyte. Hydrolysis of the substrate, mediated by phospholipase A₂, leads to the formation of water-soluble products from the insoluble substrate. This results in desorption of these products into aqueous phase and corresponding increase of the electrode capacitance. The requirement of high water solubility of the reaction products can be achieved in two ways. In the first, short-chain phospholipids are used as the substrate, in which case, water-soluble products are formed and no additional reagents are required to promote desorption of these products. The sensors prepared by this strategy provide sensitive qualitative detection of phospholipases. The second way is based on the use of a water-soluble acceptor (for example, β-cyclodextrin) to solubilize the products of hydrolysis. It allows semiquantitative detection of phospholipase activity toward long-chain natural substrates. The reaction kinetics for this case was found to be monoexponential and linearly dependent on the phospholipase concentration. The detection limit of this method, as tested with phospholipase A₂ from bee venom and soy bean lecithin as the substrate, is ∼0.5 ng/mL (500 μunits/mL).}, language = {en} } @misc{MirskyRieplWolfbeis, author = {Mirsky, Vladimir M. and Riepl, Michael and Wolfbeis, Otto S.}, title = {Capacitive monitoring of protein immobilization and antigen-antibody reaction on the monomolecular films of alkylthiols adsorbed on gold electrodes}, series = {Biosensors and Bioelectronics}, volume = {12}, journal = {Biosensors and Bioelectronics}, number = {9-10}, issn = {0956-5663}, doi = {10.1016/S0956-5663(97)00053-5}, pages = {977 -- 989}, abstract = {Self-assembled monolayers of omega-mercaptohexadecanoic acid and omega-mercaptohexadecylamine on gold electrodes are stable at neutral pH and display pure capacitive behavior at frequencies around 20 Hz. Different methods of covalent immobilization of proteins on these monolayers are compared. Various reagents including succinimides, thionylchloride, p-nitrophenol and carbodiimides were used to activate the carboxy groups of the adsorbed monolayer of omega-mercaptohexadecanoic acid. Glutaraldehyde, cyanuric chloride and phenylene diisocyanate were used to activate the amino groups of the monolayer of omega-mercaptohexadecylamine. The immobilization of albumin on the activated surface was studied by capacitive measurements. The N-hydroxysuccinimide and carbodiimide methods were identified as most suitable for protein immobilization in that they did not compromise the insulating properties of the alkylthiol layer and led to maximal increase of its dielectric thickness. These approaches were used for a layer-by-layer preparation of a capacitive immunosensor. Specifically, antibodies to human serum albumin were immobilized on the alkylthiol mono-layer. Binding of the antigen led to a decrease of the electrode capacitance. The detection limit of the immunosensor is as low as 15 nM (1 mg/l).}, language = {en} }