@article{MolinnusIkenJohnenetal.2022,
  author    = {Molinnus, Denise and Iken, Heiko and Johnen, Anna Lynn and Richstein, Benjamin and Hellmich, Lena and Poghossian, Arshak and Knoch, Joachim and Sch{\"o}ning, Michael Josef},
  title     = {Miniaturized pH-Sensitive Field-Effect Capacitors with Ultrathin Ta₂O₅ Films Prepared by Atomic Layer Deposition},
  series = {physica status solidi (a) applications and materials science},
  volume    = {219},
  journal   = {physica status solidi (a) applications and materials science},
  number    = {8},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.202100660},
  pages     = {7 Seiten},
  year      = {2022},
  abstract  = {Miniaturized electrolyte-insulator-semiconductor capacitors (EISCAPs) with ultrathin gate insulators have been studied in terms of their pH-sensitive sensor characteristics: three different EISCAP systems consisting of Al-p-Si-Ta2O5(5 nm), Al-p-Si-Si3N4(1 or 2 nm)-Ta2O5 (5 nm), and Al-p-Si-SiO2(3.6 nm)-Ta2O5(5 nm) layer structures are characterized in buffer solution with different pH values by means of capacitance-voltage and constant capacitance method. The SiO2 and Si3N4 gate insulators are deposited by rapid thermal oxidation and rapid thermal nitridation, respectively, whereas the Ta2O5 film is prepared by atomic layer deposition. All EISCAP systems have a clear pH response, favoring the stacked gate insulators SiO2-Ta2O5 when considering the overall sensor characteristics, while the Si3N4(1 nm)-Ta2O5 stack delivers the largest accumulation capacitance (due to the lower equivalent oxide thickness) and a higher steepness in the slope of the capacitance-voltage curve among the studied stacked gate insulator systems.},
  language  = {en}
}
@article{PoghossianKarschuckWagneretal.2022,
  author    = {Poghossian, Arshak and Karschuck, Tobias and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Field-Effect Capacitors Decorated with Ligand-Stabilized Gold Nanoparticles: Modeling and Experiments},
  series = {Biosensors},
  volume    = {12},
  journal   = {Biosensors},
  number    = {5},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2079-6374},
  doi       = {10.3390/bios12050334},
  pages     = {Artikel 334},
  year      = {2022},
  abstract  = {Nanoparticles are recognized as highly attractive tunable materials for designing field-effect biosensors with enhanced performance. In this work, we present a theoretical model for electrolyte-insulator-semiconductor capacitors (EISCAP) decorated with ligand-stabilized charged gold nanoparticles. The charged AuNPs are taken into account as additional, nanometer-sized local gates. The capacitance-voltage (C-V) curves and constant-capacitance (ConCap) signals of the AuNP-decorated EISCAPs have been simulated. The impact of the AuNP coverage on the shift of the C-V curves and the ConCap signals was also studied experimentally on Al-p-Si-SiO₂ EISCAPs decorated with positively charged aminooctanethiol-capped AuNPs. In addition, the surface of the EISCAPs, modified with AuNPs, was characterized by scanning electron microscopy for different immobilization times of the nanoparticles.},
  language  = {en}
}
@article{PourshahidiAchtsnichtOffenhaeusseretal.2022,
  author    = {Pourshahidi, Ali Mohammad and Achtsnicht, Stefan and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim},
  title     = {Frequency Mixing Magnetic Detection Setup Employing Permanent Ring Magnets as a Static Offset Field Source},
  series = {Sensors},
  volume    = {22},
  journal   = {Sensors},
  number    = {22},
  editor    = {Offenh{\"a}usser, Andreas},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s22228776},
  pages     = {12 Seiten},
  year      = {2022},
  abstract  = {Frequency mixing magnetic detection (FMMD) has been explored for its applications in fields of magnetic biosensing, multiplex detection of magnetic nanoparticles (MNP) and the determination of core size distribution of MNP samples. Such applications rely on the application of a static offset magnetic field, which is generated traditionally with an electromagnet. Such a setup requires a current source, as well as passive or active cooling strategies, which directly sets a limitation based on the portability aspect that is desired for point of care (POC) monitoring applications. In this work, a measurement head is introduced that involves the utilization of two ring-shaped permanent magnets to generate a static offset magnetic field. A steel cylinder in the ring bores homogenizes the field. By variation of the distance between the ring magnets and of the thickness of the steel cylinder, the magnitude of the magnetic field at the sample position can be adjusted. Furthermore, the measurement setup is compared to the electromagnet offset module based on measured signals and temperature behavior.},
  language  = {en}
}
@article{VahidpourGuthmanArreolaetal.2022,
  author    = {Vahidpour, Farnoosh and Guthman, Eric and Arreola, Julia and Alghazali, Yousef H. M. and Wagner, Torsten and Sch{\"o}ning, Michael Josef},
  title     = {Assessment of Various Process Parameters for Optimized Sterilization Conditions Using a Multi-Sensing Platform},
  series = {Foods},
  volume    = {11},
  journal   = {Foods},
  number    = {5},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2304-8158},
  doi       = {10.3390/foods11050660},
  pages     = {Artikel 660},
  year      = {2022},
  abstract  = {In this study, an online multi-sensing platform was engineered to simultaneously evaluate various process parameters of food package sterilization using gaseous hydrogen peroxide (H₂O₂). The platform enabled the validation of critical aseptic parameters. In parallel, one series of microbiological count reduction tests was performed using highly resistant spores of B. atrophaeus DSM 675 to act as the reference method for sterility validation. By means of the multi-sensing platform together with microbiological tests, we examined sterilization process parameters to define the most effective conditions with regards to the highest spore kill rate necessary for aseptic packaging. As these parameters are mutually associated, a correlation between different factors was elaborated. The resulting correlation indicated the need for specific conditions regarding the applied H₂O₂ gas temperature, the gas flow and concentration, the relative humidity and the exposure time. Finally, the novel multi-sensing platform together with the mobile electronic readout setup allowed for the online and on-site monitoring of the sterilization process, selecting the best conditions for sterility and, at the same time, reducing the use of the time-consuming and costly microbiological tests that are currently used in the food package industry.},
  language  = {en}
}
@article{VahidpourAlghazaliAkcaetal.2022,
  author    = {Vahidpour, Farnoosh and Alghazali, Yousef and Akca, Sevilay and Hommes, Gregor and Sch{\"o}ning, Michael Josef},
  title     = {An Enzyme-Based Interdigitated Electrode-Type Biosensor for Detecting Low Concentrations of H₂O₂ Vapor/Aerosol},
  series = {Chemosensors},
  volume    = {10},
  journal   = {Chemosensors},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2227-9040},
  doi       = {10.3390/chemosensors10060202},
  pages     = {Arikel 202},
  year      = {2022},
  abstract  = {This work introduces a novel method for the detection of H₂O₂ vapor/aerosol of low concentrations, which is mainly applied in the sterilization of equipment in medical industry. Interdigitated electrode (IDE) structures have been fabricated by means of microfabrication techniques. A differential setup of IDEs was prepared, containing an active sensor element (active IDE) and a passive sensor element (passive IDE), where the former was immobilized with an enzymatic membrane of horseradish peroxidase that is selective towards H₂O₂. Changes in the IDEs' capacitance values (active sensor element versus passive sensor element) under H₂O₂ vapor/aerosol atmosphere proved the detection in the concentration range up to 630 ppm with a fast response time (<60 s). The influence of relative humidity was also tested with regard to the sensor signal, showing no cross-sensitivity. The repeatability assessment of the IDE biosensors confirmed their stable capacitive signal in eight subsequent cycles of exposure to H₂O₂ vapor/aerosol. Room-temperature detection of H₂O₂ vapor/aerosol with such miniaturized biosensors will allow a future three-dimensional, flexible mapping of aseptic chambers and help to evaluate sterilization assurance in medical industry.},
  language  = {en}
}
@techreport{SiegertBongaertsWagneretal.2022,
  author    = {Siegert, Petra and Bongaerts, Johannes and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Selmer, Thorsten},
  title     = {Abschlussbericht zum Projekt zur {\"U}berwachung biotechnologischer Prozesse mittels Diacetyl-/Acetoin-Biosensor und Evaluierung von Acetoin-Reduktasen zur Verwendung in Biotransformationen},
  address   = {Aachen},
  organization    = {FH Aachen},
  pages     = {16 Seiten},
  year      = {2022},
  language  = {de}
}
@article{HaegerGrankinWagner2023,
  author    = {Haeger, Gerrit and Grankin, Alina and Wagner, Michaela},
  title     = {Construction of an Aspergillus oryzae triple amylase deletion mutant as a chassis to evaluate industrially relevant amylases using multiplex CRISPR/Cas9 editing technology},
  series = {Applied Research},
  journal   = {Applied Research},
  number    = {Early View},
  publisher = {Wiley-VCH},
  issn      = {2702-4288},
  doi       = {10.1002/appl.202200106},
  pages     = {1 -- 15},
  year      = {2023},
  abstract  = {Aspergillus oryzae is an industrially relevant organism for the secretory production of heterologous enzymes, especially amylases. The activities of potential heterologous amylases, however, cannot be quantified directly from the supernatant due to the high background activity of native α-amylase. This activity is caused by the gene products of amyA, amyB, and amyC. In this study, an in vitro CRISPR/Cas9 system was established in A. oryzae to delete these genes simultaneously. First, pyrG of A. oryzae NSAR1 was mutated by exploiting NHEJ to generate a counter-selection marker. Next, all amylase genes were deleted simultaneously by co-transforming a repair template carrying pyrG of Aspergillus nidulans and flanking sequences of amylase gene loci. The rate of obtained triple knock-outs was 47\%. We showed that triple knockouts do not retain any amylase activity in the supernatant. The established in vitro CRISPR/Cas9 system was used to achieve sequence-specific knock-in of target genes. The system was intended to incorporate a single copy of the gene of interest into the desired host for the development of screening methods. Therefore, an integration cassette for the heterologous Fpi amylase was designed to specifically target the amyB locus. The site-specific integration rate of the plasmid was 78\%, with exceptional additional integrations. Integration frequency was assessed via qPCR and directly correlated with heterologous amylase activity. Hence, we could compare the efficiency between two different signal peptides. In summary, we present a strategy to exploit CRISPR/Cas9 for gene mutation, multiplex knock-out, and the targeted knock-in of an expression cassette in A. oryzae. Our system provides straightforward strain engineering and paves the way for development of fungal screening systems.},
  language  = {en}
}
@article{HaegerWirgesTanzmannetal.2023,
  author    = {Haeger, Gerrit and Wirges, Jessika and Tanzmann, Nicole and Oyen, Sven and Jolmes, Tristan and Jaeger, Karl-Erich and Sch{\"o}rken, Ulrich and Bongaerts, Johannes and Siegert, Petra},
  title     = {Chaperone assisted recombinant expression of a mycobacterial aminoacylase in Vibrio natriegens and Escherichia coli capable of N-lauroyl-L-amino acid synthesis},
  series = {Microbial Cell Factories},
  journal   = {Microbial Cell Factories},
  number    = {22},
  publisher = {Springer Nature},
  issn      = {1475-2859},
  doi       = {10.1186/s12934-023-02079-1},
  pages     = {Article number: 77 (2023)},
  year      = {2023},
  abstract  = {Background Aminoacylases are highly promising enzymes for the green synthesis of acyl-amino acids, potentially replacing the environmentally harmful Schotten-Baumann reaction. Long-chain acyl-amino acids can serve as strong surfactants and emulsifiers, with application in cosmetic industries. Heterologous expression of these enzymes, however, is often hampered, limiting their use in industrial processes. Results We identified a novel mycobacterial aminoacylase gene from Mycolicibacterium smegmatis MKD 8, cloned and expressed it in Escherichia coli and Vibrio natriegens using the T7 overexpression system. The recombinant enzyme was prone to aggregate as inclusion bodies, and while V. natriegens Vmax™ could produce soluble aminoacylase upon induction with isopropyl β-d-1-thiogalactopyranoside (IPTG), E. coli BL21 (DE3) needed autoinduction with lactose to produce soluble recombinant protein. We successfully conducted a chaperone co-expression study in both organisms to further enhance aminoacylase production and found that overexpression of chaperones GroEL/S enhanced aminoacylase activity in the cell-free extract 1.8-fold in V. natriegens and E. coli. Eventually, E. coli ArcticExpress™ (DE3), which co-expresses cold-adapted chaperonins Cpn60/10 from Oleispira antarctica, cultivated at 12 °C, rendered the most suitable expression system for this aminoacylase and exhibited twice the aminoacylase activity in the cell-free extract compared to E. coli BL21 (DE3) with GroEL/S co-expression at 20 °C. The purified aminoacylase was characterized based on hydrolytic activities, being most stable and active at pH 7.0, with a maximum activity at 70 °C, and stability at 40 °C and pH 7.0 for 5 days. The aminoacylase strongly prefers short-chain acyl-amino acids with smaller, hydrophobic amino acid residues. Several long-chain amino acids were fairly accepted in hydrolysis as well, especially N-lauroyl-L-methionine. To initially evaluate the relevance of this aminoacylase for the synthesis of N-acyl-amino acids, we demonstrated that lauroyl-methionine can be synthesized from lauric acid and methionine in an aqueous system. Conclusion Our results suggest that the recombinant enzyme is well suited for synthesis reactions and will thus be further investigated.},
  language  = {en}
}
@techreport{HaegerBongaertsSiegert2023,
  author    = {Haeger, Gerrit and Bongaerts, Johannes and Siegert, Petra},
  title     = {Abschlussbericht Teil II: Eingehende Darstellung Neue biobasierte Lipopeptide aus nachhaltiger Produktion (LipoPep)},
  pages     = {17Seiten},
  year      = {2023},
  language  = {de}
}
@article{JanusAchtsnichtTempeletal.2023,
  author    = {Janus, Kevin Alexander and Achtsnicht, Stefan and Tempel, Laura and Drinic, Aleksaner and Kopp, Alexander and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Influence of fibroin membrane composition and curing parameters on the performance of a biodegradable enzymatic biosensor manufactured from Silicon-Free Carbon},
  series = {Physica status solidi : pss. A, Applications and materials science},
  volume    = {220},
  journal   = {Physica status solidi : pss. A, Applications and materials science},
  number    = {22},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6300 (Print)},
  doi       = {10.1002/pssa.202300081},
  pages     = {Artikel 2300081},
  year      = {2023},
  abstract  = {Herein, fibroin, polylactide (PLA), and carbon are investigated for their suitability as biocompatible and biodegradable materials for amperometric biosensors. For this purpose, screen-printed carbon electrodes on the biodegradable substrates fibroin and PLA are modified with a glucose oxidase membrane and then encapsulated with the biocompatible material Ecoflex. The influence of different curing parameters of the carbon electrodes on the resulting biosensor characteristics is studied. The morphology of the electrodes is investigated by scanning electron microscopy, and the biosensor performance is examined by amperometric measurements of glucose (0.5-10 mM) in phosphate buffer solution, pH 7.4, at an applied potential of 1.2 V versus a Ag/AgCl reference electrode. Instead of Ecoflex, fibroin, PLA, and wound adhesive are tested as alternative encapsulation compounds: a series of swelling tests with different fibroin compositions, PLA, and Ecoflex has been performed before characterizing the most promising candidates by chronoamperometry. Therefore, the carbon electrodes are completely covered with the particular encapsulation material. Chronoamperometric measurements with H2O2 concentrations between 0.5 and 10 mM enable studying the leakage current behavior.},
  language  = {en}
}