@article{PolleyBasakHassetal.2019, author = {Polley, Nabarun and Basak, Supratim and Hass, Roland and Pacholski, Claudia}, title = {Fiber optic plasmonic sensors}, series = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics}, volume = {132}, journal = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics}, publisher = {Elsevier}, address = {Oxford}, issn = {0956-5663}, doi = {10.1016/j.bios.2019.03.020}, pages = {368 -- 374}, year = {2019}, abstract = {A simple, convenient, and inexpensive method to fabricate optical fiber based biosensors which utilize periodic hole arrays in gold films for signal transduction is reported. The process of hole array formation mainly relies on self-assembly of hydrogel microgels in combination with chemical gold film deposition and subsequent transfer of the perforated film onto an optical fiber tip. In the fabrication process solely chemical wet lab techniques are used, avoiding cost-intensive instrumentation or clean room facilities. The presented method for preparing fiber optic plasmonic sensors provides high throughput and is perfectly suited for commercialization using batch processing. The transfer of the perforated gold film onto an optical fiber tip does not affect the sensitivity of the biosensor ((420 +/- 83) nm/refractive index unit (RIU)), which is comparable to sensitivities of sensor platforms based on periodic hole arrays in gold films prepared by significantly more complex methods. Furthermore, real-time and in-line immunoassay studies with a specially designed 3D printed flow cell are presented exploiting the presented optical fiber based biosensors.}, language = {en} } @article{PinyouRuffPoelleretal.2016, author = {Pinyou, Piyanut and Ruff, Adrian and Poeller, Sascha and Alsaoub, Sabine and Leimk{\"u}hler, Silke and Wollenberger, Ursula and Schuhmann, Wolfgang}, title = {Wiring of the aldehyde oxidoreductase PaoABC to electrode surfaces via entrapment in low potential phenothiazine-modified redox polymers}, series = {Bioelectrochemistry : an international journal devoted to electrochemical aspects of biology and biological aspects of electrochemistry ; official journal of the Bioelectrochemical Society}, volume = {109}, journal = {Bioelectrochemistry : an international journal devoted to electrochemical aspects of biology and biological aspects of electrochemistry ; official journal of the Bioelectrochemical Society}, publisher = {Elsevier}, address = {Lausanne}, issn = {1567-5394}, doi = {10.1016/j.bioelechem.2015.12.005}, pages = {24 -- 30}, year = {2016}, abstract = {Phenothiazine-modified redox hydrogels were synthesized and used for the wiring of the aldehyde oxidoreductase PaoABC to electrode surfaces. The effects of the pH value and electrode surface modification on the biocatalytic activity of the layers were studied in the presence of vanillin as the substrate. The enzyme electrodes were successfully employed as bioanodes in vanillin/O-2 biofuel cells in combination with a high potential bilirubin oxidase biocathode. Open circuit voltages of around 700 mV could be obtained in a two compartment biofuel cell setup. Moreover, the use of a rather hydrophobic polymer with a high degree of crosslinking sites ensures the formation of stable polymer/enzyme films which were successfully used as bioanode in membrane-less biofuel cells. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} } @article{BadalyanNeumannSchaalLeimkuehleretal.2013, author = {Badalyan, Artavazd and Neumann-Schaal, Meina and Leimk{\"u}hler, Silke and Wollenberger, Ursula}, title = {A Biosensor for aromatic aldehydes comprising the mediator dependent PaoABC-Aldehyde oxidoreductase}, series = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis}, volume = {25}, journal = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis}, number = {1}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1040-0397}, doi = {10.1002/elan.201200362}, pages = {101 -- 108}, year = {2013}, abstract = {A novel aldehyde oxidoreductase (PaoABC) from Escherichia coli was utilized for the development of an oxygen insensitive biosensor for benzaldehyde. The enzyme was immobilized in polyvinyl alcohol and currents were measured for aldehyde oxidation with different one and two electron mediators with the highest sensitivity for benzaldehyde in the presence of hexacyanoferrate(III). The benzaldehyde biosensor was optimized with respect to mediator concentration, enzyme loading and pH using potassium hexacyanoferrate(III). The linear measuring range is between 0.5200 mu M benzaldehyde. In correspondence with the substrate selectivity of the enzyme in solution the biosensor revealed a preference for aromatic aldehydes and less effective conversion of aliphatic aldehydes. The biosensor is oxygen independent, which is a particularly attractive feature for application. The biosensor can be applied to detect contaminations with benzaldehyde in solvents such as benzyl alcohol, where traces of benzaldehyde in benzyl alcohol down to 0.0042?\% can be detected.}, language = {en} } @article{FrascaMilanGuietetal.2013, author = {Frasca, Stefano and Milan, Anabel Molero and Guiet, Amandine and Goebel, Caren and Perez-Caballero, Fernando and Stiba, Konstanze and Leimk{\"u}hler, Silke and Fischer, Anna and Wollenberger, Ursula}, title = {Bioelectrocatalysis at mesoporous antimony doped tin oxide electrodes-Electrochemical characterization and direct enzyme communication}, series = {ELECTROCHIMICA ACTA}, volume = {110}, journal = {ELECTROCHIMICA ACTA}, number = {2}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {OXFORD}, issn = {0013-4686}, doi = {10.1016/j.electacta.2013.03.144}, pages = {172 -- 180}, year = {2013}, abstract = {In this paper we report immobilization and bioelectrocatalysis of human sulfite oxidase (hSO) on nanostructured antimony doped tin oxide (ATO) thin film electrodes. Two types of ATO thin film electrodes were prepared via evaporation induced self-assembly of ATO nanoparticle sols. The use of a porogen results in different porosity and film thickness. Nevertheless both electrode types reveal similar quasi reversible electrochemical behavior for positive and negatively charged small mediators. Facile and durable immobilization of catalytically active enzyme in a direct electron transfer configuration was achieved without further chemical modification of the ATO surfaces. Interestingly, the binding of hSO onto the ATO surface seems to be not only of electrostatic nature, but also originates from a strong interaction between the histidine-tag of the enzyme and the supporting material. This is suggested from stable sulfite dependent bioelectrocatalytic signals at high ionic strength and imidazole desorption experiments. As such, ATO appears as a promising conductive platform for the immobilization of complex enzymes and their application in bioelectrocatalysis. (C) 2013 Elsevier Ltd. All rights reserved.}, language = {en} }