TY - GEN A1 - Mirsky, Vladimir M. A1 - Wrobel, Nadia A1 - Riepl, Michael A1 - Hirsch, Thomas A1 - Wolfbeis, Otto S. T1 - Intelligente Nanostrukturen für Biosensoren und Sensor-Arrays T2 - BioTec: Zeitschrift für Biotechnologie Y1 - 1999 SN - 0937-2725 VL - 10 SP - 28 EP - 32 ER - TY - CHAP A1 - Wrobel, Nadia A1 - Riepl, Michael A1 - Schinkinger, Manfred A1 - Mirsky, Vladimir M. A1 - Wolfbeis, Otto S. T1 - Capacitive thin film biosensors for bacteriophages and nucleic acids T2 - Proceedings, EMBEC ’99, November 4 - 7, 1999, Vienna, Austria Y1 - 1999 SP - 362 EP - 363 PB - IFMBE CY - Stevenage ER - TY - GEN A1 - Riepl, Michael A1 - Mirsky, Vladimir M. A1 - Novotny, Ivan A1 - Tvarozek, Vladimir A1 - Rehacek, Vlastimil A1 - Wolfbeis, Otto S. T1 - Optimization of capacitive affinity sensors: drift suppression and signal amplification T2 - Analytica Chimica Acta N2 - 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. KW - Affinity sensor KW - Self-assembly KW - Capacitive sensor KW - Signal amplification KW - Immunosensor KW - Biosensor Y1 - 1999 U6 - https://doi.org/10.1016/S0003-2670(99)00195-6 SN - 0003-2670 VL - 392 IS - 1 SP - 77 EP - 84 ER - TY - GEN A1 - Riepl, Michael A1 - Mirsky, Vladimir M. A1 - Wolfbeis, Otto S. T1 - Electrical control of alkanethiols self-assembly on a gold surface as an approach for preparation of microelectrode arrays T2 - Microchimica Acta N2 - 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. KW - self-assembly KW - electrical control KW - electrode capacitance KW - addressable immobilization KW - (bio)sensor array Y1 - 1999 U6 - https://doi.org/10.1007/s006040050006 SN - 0026-3672 SN - 1436-5073 VL - 131 IS - 1 SP - 29 EP - 34 ER - TY - CHAP A1 - Mirsky, Vladimir M. A1 - Riepl, Michael A1 - Mass, Markus A1 - Hirsch, T. A1 - Schweiss, R. A1 - Wolfbeis, Otto S. ED - Vincenzini, Pietro ED - Dori, L. T1 - Capacitive detection of analyte binding in thin film chemo- and biosensors T2 - Solid State Chemical and Biochemical Sensors Y1 - 1999 SN - 88-86538-27-8 SP - 441 EP - 448 PB - Techna CY - Faenza ER -