@article{MolinnusSorichBartzetal.2016, author = {Molinnus, Denise and Sorich, Maren and Bartz, Alexander and Siegert, Petra and Willenberg, Holger S. and Lisdat, Fred and Poghossian, Arshak and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Towards an adrenaline biosensor based on substrate recycling amplification in combination with an enzyme logic gate}, series = {Sensors and Actuators B: Chemical}, volume = {237}, journal = {Sensors and Actuators B: Chemical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-4005}, doi = {10.1016/j.snb.2016.06.064}, pages = {190 -- 195}, year = {2016}, abstract = {An amperometric biosensor using a substrate recycling principle was realized for the detection of low adrenaline concentrations (1 nM) by measurements in phosphate buffer and Ringer's solution at pH 6.5 and pH 7.4, respectively. In proof-of-concept experiments, a Boolean logic-gate principle has been applied to develop a digital adrenaline biosensor based on an enzyme AND logic gate. The obtained results demonstrate that the developed digital biosensor is capable for a rapid qualitative determination of the presence/absence of adrenaline in a YES/NO statement. Such digital biosensor could be used in clinical diagnostics for the control of a correct insertion of a catheter in the adrenal veins during adrenal venous-sampling procedure.}, language = {en} } @article{MolinnusHardtSiegertetal.2018, author = {Molinnus, Denise and Hardt, Gabriel and Siegert, Petra and Willenberg, Holger S. and Poghossian, Arshak and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Detection of Adrenaline in Blood Plasma as Biomarker for Adrenal Venous Sampling}, series = {Electroanalysis}, volume = {30}, journal = {Electroanalysis}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1521-4109}, doi = {10.1002/elan.201800026}, pages = {937 -- 942}, year = {2018}, abstract = {An amperometric bi-enzyme biosensor based on substrate recycling principle for the amplification of the sensor signal has been developed for the detection of adrenaline in blood. Adrenaline can be used as biomarker verifying successful adrenal venous sampling procedure. The adrenaline biosensor has been realized via modification of a galvanic oxygen sensor with a bi-enzyme membrane combining a genetically modified laccase and a pyrroloquinoline quinone-dependent glucose dehydrogenase. The measurement conditions such as pH value and temperature were optimized to enhance the sensor performance. A high sensitivity and a low detection limit of about 0.5-1 nM adrenaline have been achieved in phosphate buffer at pH 7.4, relevant for measurements in blood samples. The sensitivity of the biosensor to other catecholamines such as noradrenaline, dopamine and dobutamine has been studied. Finally, the sensor has been successfully applied for the detection of adrenaline in human blood plasma.}, language = {en} } @article{MolinnusMuschallikGonzalezetal.2018, author = {Molinnus, Denise and Muschallik, Lukas and Gonzalez, Laura Osorio and Bongaerts, Johannes and Wagner, Torsten and Selmer, Thorsten and Siegert, Petra and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Development and characterization of a field-effect biosensor for the detection of acetoin}, series = {Biosensors and Bioelectronics}, volume = {115}, journal = {Biosensors and Bioelectronics}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.bios.2018.05.023}, pages = {1 -- 6}, year = {2018}, abstract = {A capacitive electrolyte-insulator-semiconductor (EIS) field-effect biosensor for acetoin detection has been presented for the first time. The EIS sensor consists of a layer structure of Al/p-Si/SiO₂/Ta₂O₅/enzyme acetoin reductase. The enzyme, also referred to as butane-2,3-diol dehydrogenase from B. clausii DSM 8716T, has been recently characterized. The enzyme catalyzes the (R)-specific reduction of racemic acetoin to (R,R)- and meso-butane-2,3-diol, respectively. Two different enzyme immobilization strategies (cross-linking by using glutaraldehyde and adsorption) have been studied. Typical biosensor parameters such as optimal pH working range, sensitivity, hysteresis, linear concentration range and long-term stability have been examined by means of constant-capacitance (ConCap) mode measurements. Furthermore, preliminary experiments have been successfully carried out for the detection of acetoin in diluted white wine samples.}, language = {en} } @article{WeldenSeverinsPoghossianetal.2022, author = {Welden, Melanie and Severins, Robin and Poghossian, Arshak and Wege, Christina and Bongaerts, Johannes and Siegert, Petra and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Detection of acetoin and diacetyl by a tobacco mosaic virus-assisted field-effect biosensor}, series = {Chemosensors}, volume = {10}, journal = {Chemosensors}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {2227-9040}, doi = {10.3390/chemosensors10060218}, pages = {Artikel 218}, year = {2022}, abstract = {Acetoin and diacetyl have a major impact on the flavor of alcoholic beverages such as wine or beer. Therefore, their measurement is important during the fermentation process. Until now, gas chromatographic techniques have typically been applied; however, these require expensive laboratory equipment and trained staff, and do not allow for online monitoring. In this work, a capacitive electrolyte-insulator-semiconductor sensor modified with tobacco mosaic virus (TMV) particles as enzyme nanocarriers for the detection of acetoin and diacetyl is presented. The enzyme acetoin reductase from Alkalihalobacillus clausii DSM 8716ᵀ is immobilized via biotin-streptavidin affinity, binding to the surface of the TMV particles. The TMV-assisted biosensor is electrochemically characterized by means of leakage-current, capacitance-voltage, and constant capacitance measurements. In this paper, the novel biosensor is studied regarding its sensitivity and long-term stability in buffer solution. Moreover, the TMV-assisted capacitive field-effect sensor is applied for the detection of diacetyl for the first time. The measurement of acetoin and diacetyl with the same sensor setup is demonstrated. Finally, the successive detection of acetoin and diacetyl in buffer and in diluted beer is studied by tuning the sensitivity of the biosensor using the pH value of the measurement solution.}, language = {en} } @inproceedings{WeldenSeverinsPoghossianetal.2022, author = {Welden, Melanie and Severins, Robin and Poghossian, Arshak and Wege, Christina and Siegert, Petra and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Studying the immobilization of acetoin reductase with Tobacco mosaic virus particles on capacitive field-effect sensors}, series = {2022 IEEE International Symposium on Olfaction and Electronic Nose (ISOEN)}, booktitle = {2022 IEEE International Symposium on Olfaction and Electronic Nose (ISOEN)}, publisher = {IEEE}, isbn = {978-1-6654-5860-3 (Online)}, doi = {10.1109/ISOEN54820.2022.9789657}, pages = {4 Seiten}, year = {2022}, abstract = {A capacitive electrolyte-insulator-semiconductor (EISCAP) biosensor modified with Tobacco mosaic virus (TMV) particles for the detection of acetoin is presented. The enzyme acetoin reductase (AR) was immobilized on the surface of the EISCAP using TMV particles as nanoscaffolds. The study focused on the optimization of the TMV-assisted AR immobilization on the Ta 2 O 5 -gate EISCAP surface. The TMV-assisted acetoin EISCAPs were electrochemically characterized by means of leakage-current, capacitance-voltage, and constant-capacitance measurements. The TMV-modified transducer surface was studied via scanning electron microscopy.}, language = {en} } @article{JablonskiMuenstermannNorketal.2021, author = {Jablonski, Melanie and M{\"u}nstermann, Felix and Nork, Jasmina and Molinnus, Denise and Muschallik, Lukas and Bongaerts, Johannes and Wagner, Torsten and Keusgen, Michael and Siegert, Petra and Sch{\"o}ning, Michael Josef}, title = {Capacitive field-effect biosensor applied for the detection of acetoin in alcoholic beverages and fermentation broths}, series = {physica status solidi (a) applications and materials science}, volume = {218}, journal = {physica status solidi (a) applications and materials science}, number = {13}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.202000765}, pages = {7 Seiten}, year = {2021}, abstract = {An acetoin biosensor based on a capacitive electrolyte-insulator-semiconductor (EIS) structure modified with the enzyme acetoin reductase, also known as butane-2,3-diol dehydrogenase (Bacillus clausii DSM 8716ᵀ), is applied for acetoin detection in beer, red wine, and fermentation broth samples for the first time. The EIS sensor consists of an Al/p-Si/SiO₂/Ta₂O₅ layer structure with immobilized acetoin reductase on top of the Ta₂O₅ transducer layer by means of crosslinking via glutaraldehyde. The unmodified and enzyme-modified sensors are electrochemically characterized by means of leakage current, capacitance-voltage, and constant capacitance methods, respectively.}, language = {en} }