TY - JOUR A1 - Welden, Melanie A1 - Severins, Robin A1 - Poghossian, Arshak A1 - Wege, Christina A1 - Bongaerts, Johannes A1 - Siegert, Petra A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Detection of acetoin and diacetyl by a tobacco mosaic virus-assisted field-effect biosensor JF - Chemosensors N2 - 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. Y1 - 2022 U6 - https://doi.org/10.3390/chemosensors10060218 SN - 2227-9040 N1 - This article belongs to the Special Issue "Nanostructured Devices for Biochemical Sensing" VL - 10 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Welden, Melanie A1 - Poghossian, Arshak A1 - Vahidpour, Farnoosh A1 - Wendlandt, Tim A1 - Keusgen, Michael A1 - Wege, Christina A1 - Schöning, Michael Josef T1 - Towards multi-analyte detection with field-effect capacitors modified with tobacco mosaic virus bioparticles as enzyme nanocarriers JF - Biosensors N2 - Utilizing an appropriate enzyme immobilization strategy is crucial for designing enzyme-based biosensors. Plant virus-like particles represent ideal nanoscaffolds for an extremely dense and precise immobilization of enzymes, due to their regular shape, high surface-to-volume ratio and high density of surface binding sites. In the present work, tobacco mosaic virus (TMV) particles were applied for the co-immobilization of penicillinase and urease onto the gate surface of a field-effect electrolyte-insulator-semiconductor capacitor (EISCAP) with a p-Si-SiO₂-Ta₂O₅ layer structure for the sequential detection of penicillin and urea. The TMV-assisted bi-enzyme EISCAP biosensor exhibited a high urea and penicillin sensitivity of 54 and 85 mV/dec, respectively, in the concentration range of 0.1–3 mM. For comparison, the characteristics of single-enzyme EISCAP biosensors modified with TMV particles immobilized with either penicillinase or urease were also investigated. The surface morphology of the TMV-modified Ta₂O₅-gate was analyzed by scanning electron microscopy. Additionally, the bi-enzyme EISCAP was applied to mimic an XOR (Exclusive OR) enzyme logic gate. KW - urease KW - enzyme-logic gate KW - bi-enzyme biosensor KW - capacitive field-effect sensor KW - tobacco mosaic virus (TMV) KW - penicillinase Y1 - 2022 U6 - https://doi.org/10.3390/bios12010043 SN - 2079-6374 N1 - This article belongs to the Special Issue "Biosensors: 10th Anniversary Feature Papers" VL - 12 IS - 1 PB - MDPI CY - Basel ER - TY - JOUR A1 - Weigand, Christoph A1 - Collani, E. v. A1 - Saniga, E.M. T1 - Economic Adjustment Design for -Control Charts. E.v.Collani, E.M. Saniga, Ch. Weigand JF - IIE Transactions / Institute of Industrial Engineers. 26 (1994), H. 6 Y1 - 1994 SN - 0569-5554 ER - TY - JOUR A1 - Weigand, Christoph T1 - Economic Machine Adjustment in the Case of Product Screening .E.v.Collani, Ch. Weigand JF - Statistical Papers. 33 (1992) Y1 - 1992 SP - 171 EP - 184 ER - TY - JOUR A1 - Weigand, Christoph T1 - Defining Precisions for Reliable Measurement and Estimation Procedures JF - Economic Quality Control. 24 (2009), H. 1 Y1 - 2009 SN - 0940-5151 SP - 5 EP - 33 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Weigand, Christoph T1 - Economically Optimal Inspection Policy with Geometrical Adaption JF - Journal of Applied Statistics. 30 (2003), H. 5 Y1 - 2003 SN - 0266-4763 N1 - weitere ISSN 1360-0532 (E) SP - 555 EP - 569 ER - TY - JOUR A1 - Weigand, Christoph T1 - Economically Optimal Inspection Policy with Arithmetical Adaption JF - Applied stochastic models and data analysis / [10th International Symposium on Applied Stochastic Models and Analysis, June 12-15 2001, Université Technologique de Compiègne] ; editors Gérard Govaert, Jacques Janssen, Nikolaos Limnios. Y1 - 2001 N1 - ASDMA 2001 SP - 1010 EP - 1015 PB - Université Technologique de Compiègne CY - Compiègne ER - TY - JOUR A1 - Weigand, Christoph T1 - Optimal Production Schedule for a K Products Single Machine Problem JF - Economic Quality Control. 9 (1994) Y1 - 1994 SN - 0940-5151 SP - 91 EP - 101 ER - TY - JOUR A1 - Weigand, Christoph T1 - Statistical Tests Based on Reliability and Precision JF - Economic Quality Control : EQC ; international journal for quality and reliability N2 - The construction of a statistical test is investigated which is based only on “reliability” and “precision” as quality criteria. The reliability of a statistical test is quantifiedin a straightforward way by the probability that the decision of the test is correct. However, the quantification of the precision of a statistical test is not at all evident. Thereforethe paper presents and discusses several approaches. Moreover the distinction of “nullhypothesis” and “alternative hypothesis” is not necessary any longer. Y1 - 2012 U6 - https://doi.org/10.1515/eqc-2012-0002 SN - 1869-6147 VL - 27 IS - 1 SP - 43 EP - 64 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Weigand, Christoph T1 - A Solution to the Scheduling Problem Taking into Account Quality JF - Operations research '91 : extended abstracts of the 16th Symposium on Operations Research held at the University of Trier at September 9 - 11, 1991 / [GMÖOR]. Peter Gritzmann ... (eds.) Y1 - 1991 SN - 3790806080 N1 - Symposium on Operations Research ; (16, 1991, Trier) SP - 373 EP - 375 PB - Physica-Verl. CY - Heidelberg ER -