@incollection{DuongSeifarthTemizArtmannetal.2018, author = {Duong, Minh Tuan and Seifarth, Volker and Temiz Artmann, Ayseg{\"u}l and Artmann, Gerhard and Staat, Manfred}, title = {Growth Modelling Promoting Mechanical Stimulation of Smooth Muscle Cells of Porcine Tubular Organs in a Fibrin-PVDF Scaffold}, series = {Biological, Physical and Technical Basics of Cell Engineering}, booktitle = {Biological, Physical and Technical Basics of Cell Engineering}, editor = {Artmann, Gerhard and Temiz Artmann, Ayseg{\"u}l and Zhubanova, Azhar A. and Digel, Ilya}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-10-7904-7}, doi = {10.1007/978-981-10-7904-7_9}, pages = {209 -- 232}, year = {2018}, abstract = {Reconstructive surgery and tissue replacements like ureters or bladders reconstruction have been recently studied, taking into account growth and remodelling of cells since living cells are capable of growing, adapting, remodelling or degrading and restoring in order to deform and respond to stimuli. Hence, shapes of ureters or bladders and their microstructure change during growth and these changes strongly depend on external stimuli such as training. We present the mechanical stimulation of smooth muscle cells in a tubular fibrin-PVDFA scaffold and the modelling of the growth of tissue by stimuli. To this end, mechanotransduction was performed with a kyphoplasty balloon catheter that was guided through the lumen of the tubular structure. The bursting pressure was examined to compare the stability of the incubated tissue constructs. The results showed the significant changes on tissues with training by increasing the burst pressure as a characteristic mechanical property and the smooth muscle cells were more oriented with uniformly higher density. Besides, the computational growth models also exhibited the accurate tendencies of growth of the cells under different external stimuli. Such models may lead to design standards for the better layered tissue structure in reconstructing of tubular organs characterized as composite materials such as intestines, ureters and arteries.}, language = {en} } @incollection{StaatHeitzer2003, author = {Staat, Manfred and Heitzer, Michael}, title = {Probabilistic limit and shakedown problems}, series = {Numerical methods for limit and shakedown analysis. Deterministic and probabilistic problems}, volume = {15}, booktitle = {Numerical methods for limit and shakedown analysis. Deterministic and probabilistic problems}, editor = {Staat, Manfred and Heitzer, Michael}, publisher = {John von Neumann Institute for Computing (NIC)}, address = {J{\"u}lich}, isbn = {3-00-010001-6}, pages = {217 -- 268}, year = {2003}, language = {en} } @inproceedings{BhattaraiStaat2018, author = {Bhattarai, Aroj and Staat, Manfred}, title = {Pectopexy to repair vaginal vault prolapse: a finite element approach}, series = {Proceedings CMBBE 2018}, booktitle = {Proceedings CMBBE 2018}, editor = {Fernandes, P.R. and Tavares, J. M.}, year = {2018}, abstract = {The vaginal prolapse after hysterectomy (removal of the uterus) is often associated with the prolapse of the vaginal vault, rectum, bladder, urethra or small bowel. Minimally invasive surgery such as laparoscopic sacrocolpopexy and pectopexy are widely performed for the treatment of the vaginal prolapse with weakly supported vaginal vault after hysterectomy using prosthetic mesh implants to support (or strengthen) lax apical ligaments. Implants of different shape, size and polymers are selected depending on the patient's anatomy and the surgeon's preference. In this computational study on pectopexy, DynaMesh®-PRP soft, GYNECARE GYNEMESH® PS Nonabsorbable PROLENE® soft and Ultrapro® are tested in a 3D finite element model of the female pelvic floor. The mesh model is implanted into the extraperitoneal space and sutured to the vaginal stump with a bilateral fixation to the iliopectineal ligament at both sides. Numerical simulations are conducted at rest, after surgery and during Valsalva maneuver with weakened tissues modeled by reduced tissue stiffness. Tissues and prosthetic meshes are modeled as incompressible, isotropic hyperelastic materials. The positions of the organs are calculated with respect to the pubococcygeal line (PCL) for female pelvic floor at rest, after repair and during Valsalva maneuver using the three meshes.}, language = {en} } @article{PoghossianJablonskiKochetal.2018, author = {Poghossian, Arshak and Jablonski, Melanie and Koch, Claudia and Bronder, Thomas and Rolka, David and Wege, Christina and Sch{\"o}ning, Michael Josef}, title = {Field-effect biosensor using virus particles as scaffolds for enzyme immobilization}, series = {Biosensors and Bioelectronics}, volume = {110}, journal = {Biosensors and Bioelectronics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0956-5663}, doi = {10.1016/j.bios.2018.03.036}, pages = {168 -- 174}, year = {2018}, abstract = {A field-effect biosensor employing tobacco mosaic virus (TMV) particles as scaffolds for enzyme immobilization is presented. Nanotubular TMV scaffolds allow a dense immobilization of precisely positioned enzymes with retained activity. To demonstrate feasibility of this new strategy, a penicillin sensor has been developed by coupling a penicillinase with virus particles as a model system. The developed field-effect penicillin biosensor consists of an Al-p-Si-SiO₂-Ta₂O₅-TMV structure and has been electrochemically characterized in buffer solutions containing different concentrations of penicillin G. In addition, the morphology of the biosensor surface with virus particles was characterized by scanning electron microscopy and atomic force microscopy methods. The sensors possessed a high penicillin sensitivity of ~ 92 mV/dec in a nearly-linear range from 0.1 mM to 10 mM, and a low detection limit of about 50 µM. The long-term stability of the penicillin biosensor was periodically tested over a time period of about one year without any significant loss of sensitivity. The biosensor has also been successfully applied for penicillin detection in bovine milk samples.}, 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{BirgelLeschingerWegmannetal.2018, author = {Birgel, Stefan and Leschinger, Tim and Wegmann, Kilian and Staat, Manfred}, title = {Calculation of muscle forces and joint reaction loads in the shoulder area via an OpenSim based computer model}, series = {tm - Technisches Messen}, volume = {85}, journal = {tm - Technisches Messen}, number = {5}, publisher = {De Gruyter}, address = {Berlin}, issn = {2196-7113}, doi = {10.1515/teme-2017-0114}, pages = {321 -- 330}, year = {2018}, abstract = {Using the OpenSim software and verified anatomical data, a computer model for the calculation of biomechanical parameters is developed and used to determine the effect of a reattachment of the Supraspinatus muscle with a medial displacement of the muscle attachment point, which may be necessary for a rupture of the supraspinatus tendon. The results include the influence of the operation on basic biomechanical parameters such as the lever arm, as well as the calculated the muscle activations for the supraspinatus and deltoid. In addition, the influence on joint stability is examined by an analysis of the joint reaction force. The study provides a detailed description of the used model, as well as medical findings to a reattachment of the supraspinatus. Mit der Software OpenSim und {\"u}berpr{\"u}ften anatomischen Daten wird ein Computermodell zur Berechnung von biomechanischen Parametern entwickelt und genutzt, um den Effekt einer Refixierung des Supraspinatusmuskels mit einer medialen Verschiebung des Muskelansatzpunktes zu ermitteln, wie sie unter anderem nach einem Riss der Supraspinatussehne notwendig sein kann. Die Ergebnisse umfassen hierbei den Einfluss der Operation auf grundlegende biomechanische Parameter wie den Hebelarm sowie die berechneten Muskelaktivierungen f{\"u}r den Supraspinatus und Deltoideus. Zus{\"a}tzlich wird der Einfluss auf die Gelenkstabilit{\"a}t betrachtet und durch eine Analyse der Gelenkreaktionskraft untersucht. Die Studie bietet eine detaillierte Beschreibung des genutzten Modells, sowie medizinische Erkenntnisse zu einer Refixierung des Supraspinatus.}, language = {en} } @article{BhattaraiJabbariAndingetal.2018, author = {Bhattarai, Aroj and Jabbari, Medisa and Anding, Ralf and Staat, Manfred}, title = {Surgical treatment of vaginal vault prolapse using different prosthetic mesh implants: a finite element analysis}, series = {tm - Technisches Messen}, volume = {85}, journal = {tm - Technisches Messen}, number = {5}, publisher = {De Gruyter}, address = {Berlin}, issn = {2196-7113}, doi = {10.1515/teme-2017-0115}, pages = {331 -- 342}, year = {2018}, abstract = {Particularly multiparous elderly women may suffer from vaginal vault prolapse after hysterectomy due to weak support from lax apical ligaments. A decreased amount of estrogen and progesterone in older age is assumed to remodel the collagen thereby reducing tissue stiffness. Sacrocolpopexy is either performed as open or laparoscopic surgery using prosthetic mesh implants to substitute lax ligaments. Y-shaped mesh models (DynaMesh, Gynemesh, and Ultrapro) are implanted in a 3D female pelvic floor finite element model in the extraperitoneal space from the vaginal cuff to the first sacral (S1) bone below promontory. Numerical simulations are conducted during Valsalva maneuver with weakened tissues modeled by reduced tissue stiffness. Tissues are modeled as incompressible, isotropic hyperelastic materials whereas the meshes are modeled either as orthotropic linear elastic or as isotropic hyperlastic materials. The positions of the vaginal cuff and the bladder base are calculated from the pubococcygeal line for female pelvic floor at rest, for prolapse and after repair using the three meshes. Due to mesh mechanics and mesh pore deformation along the loaded direction, the DynaMesh with regular rectangular mesh pores is found to provide better mechanical support to the organs than the Gynemesh and the Ultrapro with irregular hexagonal mesh pores. Insbesondere {\"a}ltere, mehrgeb{\"a}hrende Frauen leiden h{\"a}ufiger an einem Scheidenvorfall nach einer Hysterektomie aufgrund der schwachen Unterst{\"u}tzung durch laxe apikale B{\"a}nder. Es wird angenommen, dass eine verringerte Menge an {\"O}strogen und Progesteron im h{\"o}heren Alter das Kollagen umformt, wodurch die Gewebesteifigkeit reduziert wird. Die Sakrokolpopexie ist eine offene oder laparoskopische Operation, die mit prothetischen Netzimplantaten durchgef{\"u}hrt wird, um laxe B{\"a}nder zu ersetzen. Y-f{\"o}rmige Netzmodelle (DynaMesh, Gynemesh und Ultrapro) werden in einem 3D-Modell des weiblichen Beckenbodens im extraperitonealen Raum vom Vaginalstumpf bis zum Promontorium implantiert. Numerische Simulationen werden w{\"a}hrend des Valsalva-Man{\"o}vers mit geschw{\"a}chtem Gewebe durchgef{\"u}hrt, das durch eine reduzierte Gewebesteifigkeit modelliert wird. Die Gewebe werden als inkompressible, isotrop hyperelastische Materialien modelliert, w{\"a}hrend die Netze entweder als orthotrope linear elastische oder als isotrope hyperlastische Materialien modelliert werden. Die Positionen des Vaginalstumpfs, der Blase und der Harnr{\"o}hrenachse werden anhand der Pubococcygeallinie aus der Ruhelage, f{\"u}r den Prolaps und nach der Reparatur unter Verwendung der drei Netze berechnet. Aufgrund der Netzmechanik und der Netzporenverformung bietet das DynaMesh mit regelm{\"a}ßigen rechteckigen Netzporen eine bessere mechanische Unterst{\"u}tzung und eine Neupositionierung des Scheidengew{\"o}lbes, der Blase und der Urethraachse als Gynemesh und Ultrapro mit unregelm{\"a}ßigen hexagonalen Netzporen.}, language = {en} } @article{KohlerKirschnerHermannsStaatetal.2018, author = {Kohler, Annette and Kirschner-Hermanns, Ruth and Staat, Manfred and Brehmer, Bernhard}, title = {Pathogenese, funktionelle und anatomische Aspekte der weiblichen Belastungsinkontinenz}, series = {Aktuelle Urologie}, volume = {49}, journal = {Aktuelle Urologie}, number = {1}, publisher = {Thieme}, address = {Stuttgart}, issn = {1438-8820}, doi = {10.1055/s-0043-120616}, pages = {47 -- 51}, year = {2018}, abstract = {Der vorliegende Artikel fokussiert sich auf die weibliche Belastungsinkontinenz als Insuffizienz der Speicherfunktion der Blase, auch wenn im klinischen Alltag die Harninkontinenz der Frau h{\"a}ufig verschiedene Ursachen hat und insbesondere eine Belastungsinkontinenz im Alter und bei neurologischer Komorbidit{\"a}t nur selten isoliert vorkommt. Das kleine Becken der Frau ist sowohl als Funktions- als auch als strukturelle Einheit zu betrachten. Dabei unterliegen bei der Frau Blase, Harnr{\"o}hre, Geb{\"a}rmutter und Enddarm sowie die muskul{\"a}ren und ligament{\"o}sen Strukturen des kleinen Beckens durch Fertilit{\"a}tsphase, m{\"o}gliche Schwangerschaften, Geburten und Menopausen-Phase, {\"u}ber das „normale Altern" hinaus, gravierenden Ver{\"a}nderungen. This article focuses on female stress incontinence in the form of pelvic floor dysfunction and urethral sphincter deficiency, although isolated stress incontinence accounts for less than half of all incontinence cases. Especially in women of old age and those with neurological comorbidities, the causes of incontinence are mostly multifactorial. Also it has to be considered that the female bladder, urethra, uterus and rectum as well as the muscular and ligamentous structures of the female pelvis minor are affected by phases of fertility, possible pregnancies, births and menopause in addition to the normal ageing process.}, language = {de} } @article{BhattaraiStaat2018, author = {Bhattarai, Aroj and Staat, Manfred}, title = {Modelling of Soft Connective Tissues to Investigate Female Pelvic Floor Dysfunctions}, series = {Computational and Mathematical Methods in Medicine}, volume = {2018}, journal = {Computational and Mathematical Methods in Medicine}, number = {Article ID 9518076}, publisher = {Hindawi}, address = {New York, NY}, issn = {1748-6718}, doi = {10.1155/2018/9518076}, pages = {1 -- 16}, year = {2018}, abstract = {After menopause, decreased levels of estrogen and progesterone remodel the collagen of the soft tissues thereby reducing their stiffness. Stress urinary incontinence is associated with involuntary urine leakage due to pathological movement of the pelvic organs resulting from lax suspension system, fasciae, and ligaments. This study compares the changes in the orientation and position of the female pelvic organs due to weakened fasciae, ligaments, and their combined laxity. A mixture theory weighted by respective volume fraction of elastin-collagen fibre compound (5\%), adipose tissue (85\%), and smooth muscle (5\%) is adopted to characterize the mechanical behaviour of the fascia. The load carrying response (other than the functional response to the pelvic organs) of each fascia component, pelvic organs, muscles, and ligaments are assumed to be isotropic, hyperelastic, and incompressible. Finite element simulations are conducted during Valsalva manoeuvre with weakened tissues modelled by reduced tissue stiffness. A significant dislocation of the urethrovesical junction is observed due to weakness of the fascia (13.89 mm) compared to the ligaments (5.47 mm). The dynamics of the pelvic floor observed in this study during Valsalva manoeuvre is associated with urethral-bladder hypermobility, greater levator plate angulation, and positive Q-tip test which are observed in incontinent females.}, language = {en} } @inproceedings{SchmidtsBoltesKraftetal.2017, author = {Schmidts, Oliver and Boltes, Maik and Kraft, Bodo and Schreiber, Marc}, title = {Multi-pedestrian tracking by moving Bluetooth-LE beacons and stationary receivers}, series = {2017 International Conference on Indoor Positioning and Indoor Navigation (IPIN), 18-21 September 2017, Sapporo, Japan}, booktitle = {2017 International Conference on Indoor Positioning and Indoor Navigation (IPIN), 18-21 September 2017, Sapporo, Japan}, pages = {1 -- 4}, year = {2017}, language = {en} } @incollection{BhattaraiFrotscherStaat2018, author = {Bhattarai, Aroj and Frotscher, Ralf and Staat, Manfred}, title = {Computational Analysis of Pelvic Floor Dysfunction}, series = {Women's Health and Biomechanics}, booktitle = {Women's Health and Biomechanics}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-71574-2}, doi = {10.1007/978-3-319-71574-2_17}, pages = {217 -- 230}, year = {2018}, abstract = {Pelvic floor dysfunction (PFD) is characterized by the failure of the levator ani (LA) muscle to maintain the pelvic hiatus, resulting in the descent of the pelvic organs below the pubococcygeal line. This chapter adopts the modified Humphrey material model to consider the effect of the muscle fiber on passive stretching of the LA muscle. The deformation of the LA muscle subjected to intra-abdominal pressure during Valsalva maneuver is compared with the magnetic resonance imaging (MRI) examination of a nulliparous female. Numerical result shows that the fiber-based Humphrey model simulates the muscle behavior better than isotropic constitutive models. Greater posterior movement of the LA muscle widens the levator hiatus due to lack of support from the anococcygeal ligament and the perineal structure as a consequence of birth-related injury and aging. Old and multiparous females with uncontrolled urogenital and rectal hiatus tend to develop PFDs such as prolapse and incontinence.}, language = {en} } @article{OberlaenderMayerGreeffetal.2018, author = {Oberl{\"a}nder, Jan and Mayer, Marlena and Greeff, Anton and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Spore-based biosensor to monitor the microbicidal efficacy of gaseous hydrogen peroxide sterilization processes}, series = {Biosensors and Bioelectronics}, volume = {104}, journal = {Biosensors and Bioelectronics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0956-5663}, doi = {10.1016/j.bios.2017.12.045}, pages = {87 -- 94}, year = {2018}, abstract = {In this work, a spore-based biosensor is evaluated to monitor the microbicidal efficacy of sterilization processes applying gaseous hydrogen peroxide (H2O2). The sensor is based on interdigitated electrode structures (IDEs) that have been fabricated by means of thin-film technologies. Impedimetric measurements are applied to study the effect of sterilization process on spores of Bacillus atrophaeus. This resilient microorganism is commonly used in industry to proof the sterilization efficiency. The sensor measurements are accompanied by conventional microbiological challenge tests, as well as morphological characterizations with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The sensor measurements are correlated with the microbiological test routines. In both methods, namely the sensor-based and microbiological one, a tailing effect has been observed. The results are evaluated and discussed in a three-dimensional calibration plot demonstrating the sensor's suitability to enable a rapid process decision in terms of a successfully performed sterilization.}, language = {en} } @article{BreuerMangSchoeningetal.2017, author = {Breuer, Lars and Mang, Thomas and Sch{\"o}ning, Michael Josef and Thoelen, Ronald and Wagner, Torsten}, title = {Investigation of the spatial resolution of a laser-based stimulation process for light-addressable hydrogels with incorporated graphene oxide by means of IR thermography}, series = {Sensors and Actuators A: Physical}, volume = {268}, journal = {Sensors and Actuators A: Physical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0924-4247}, doi = {10.1016/j.sna.2017.11.031}, pages = {126 -- 132}, year = {2017}, language = {en} } @article{KotliarHauserOrtneretal.2017, author = {Kotliar, Konstantin and Hauser, Christine and Ortner, Marion and Muggenthaler, Claudia and Diehl-Schmid, Janine and Angermann, Susanne and Hapfelmeier, Alexander and Schmaderer, Christoph and Grimmer, Timo}, title = {Altered neurovascular coupling as measured by optical imaging: a biomarker for Alzheimer's disease}, series = {Scientific Reports}, volume = {7}, journal = {Scientific Reports}, number = {1}, publisher = {Springer Nature}, address = {Cham}, issn = {2045-2322}, doi = {10.1038/s41598-017-13349-5}, pages = {1 -- 11}, year = {2017}, language = {en} } @article{GaribaldiBegingCaneseetal.2017, author = {Garibaldi, F. and Beging, Stefan and Canese, R. and Carpinelli, G. and Clinthorne, N. and Colilli, S. and Cosentino, L. and Finocchiaro, P. and Giuliani, F. and Gricia, M. and Lucentini, M. and Majewski, S. and Monno, E. and Musico, P. and Santavenere, F. and T{\"o}dter, J. and Wegener, Hans-Peter and Ziemons, Karl}, title = {A novel TOF-PET MRI detector for diagnosis and follow up of the prostate cancer}, series = {European Physical Journal Plus}, volume = {132}, journal = {European Physical Journal Plus}, number = {9}, publisher = {Springer}, address = {Berlin}, issn = {2190-5444}, doi = {10.1140/epjp/i2017-11662-x}, year = {2017}, language = {en} } @misc{HacklWegmannKahmannetal.2017, author = {Hackl, Michael and Wegmann, Kilian and Kahmann, Stephanie Lucina and Heinze, Nicolai and Staat, Manfred and Neiss, Wolfram F. and Scaal, Martin and M{\"u}ller, Lars P.}, title = {Reply to the letter to the editor: shortening osteotomy of the proximal radius}, series = {Knee Surgery, Sports Traumatology, Arthroscopy}, volume = {25}, journal = {Knee Surgery, Sports Traumatology, Arthroscopy}, number = {10}, doi = {10.1007/s00167-017-4666-8}, pages = {3328 -- 3329}, year = {2017}, language = {en} } @inproceedings{BreuerGuthmannSchoeningetal.2017, author = {Breuer, Lars and Guthmann, Eric and Sch{\"o}ning, Michael Josef and Thoelen, Ronald and Wagner, Torsten}, title = {Light-Stimulated Hydrogels with Incorporated Graphene Oxide as Actuator Material for Flow Control in Microfluidic Applications}, series = {Proceedings Eurosensors 2017 Conference, Paris, France, 3-6 September 2017}, booktitle = {Proceedings Eurosensors 2017 Conference, Paris, France, 3-6 September 2017}, doi = {10.3390/proceedings1040524}, pages = {1 -- 4}, year = {2017}, language = {en} } @article{AlbannaLuekeSjapicetal.2017, author = {Albanna, Walid and Lueke, Jan Niklas and Sjapic, Volha and Kotliar, Konstantin and Hescheler, J{\"u}rgen and Clusmann, Hans and Sjapic, Sergej and Alpdogan, Serdan and Schneider, Toni and Schubert, Gerrit Alexander and Neumaier, Felix}, title = {Electroretinographic Assessment of Inner Retinal Signaling in the Isolated and Superfused Murine Retina}, series = {Current Eye Research}, journal = {Current Eye Research}, number = {Article in press}, publisher = {Taylor \& Francis}, address = {London}, issn = {1460-2202}, doi = {10.1080/02713683.2017.1339807}, pages = {1 -- 9}, year = {2017}, language = {en} } @article{PilasYaziciSelmeretal.2017, author = {Pilas, Johanna and Yazici, Yasemen and Selmer, Thorsten and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Optimization of an amperometric biosensor array for simultaneous measurement of ethanol, formate, d- and l-lactate}, series = {Electrochimica Acta}, volume = {251}, journal = {Electrochimica Acta}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0013-4686}, doi = {10.1016/j.electacta.2017.07.119}, pages = {256 -- 262}, year = {2017}, abstract = {The immobilization of NAD+-dependent dehydrogenases, in combination with a diaphorase, enables the facile development of multiparametric sensing devices. In this work, an amperometric biosensor array for simultaneous determination of ethanol, formate, d- and l-lactate is presented. Enzyme immobilization on platinum thin-film electrodes was realized by chemical cross-linking with glutaraldehyde. The optimization of the sensor performance was investigated with regard to enzyme loading, glutaraldehyde concentration, pH, cofactor concentration and temperature. Under optimal working conditions (potassium phosphate buffer with pH 7.5, 2.5 mmol L-1 NAD+, 2.0 mmol L-1 ferricyanide, 25 °C and 0.4\% glutaraldehyde) the linear working range and sensitivity of the four sensor elements was improved. Simultaneous and cross-talk free measurements of four different metabolic parameters were performed successfully. The reliable analytical performance of the biosensor array was demonstrated by application in a clarified sample of inoculum sludge. Thereby, a promising approach for on-site monitoring of fermentation processes is provided.}, language = {en} } @article{RoehlenPilasSchoeningetal.2017, author = {R{\"o}hlen, Desiree and Pilas, Johanna and Sch{\"o}ning, Michael Josef and Selmer, Thorsten}, title = {Development of an amperometric biosensor platform for the combined determination of l-Malic, Fumaric, and l-Aspartic acid}, series = {Applied Biochemistry and Biotechnology}, volume = {183}, journal = {Applied Biochemistry and Biotechnology}, publisher = {Springer}, address = {Berlin}, issn = {1559-0291}, doi = {10.1007/s12010-017-2578-1}, pages = {566 -- 581}, year = {2017}, abstract = {Three amperometric biosensors have been developed for the detection of L-malic acid, fumaric acid, and L -aspartic acid, all based on the combination of a malate-specific dehydrogenase (MDH, EC 1.1.1.37) and diaphorase (DIA, EC 1.8.1.4). The stepwise expansion of the malate platform with the enzymes fumarate hydratase (FH, EC 4.2.1.2) and aspartate ammonia-lyase (ASPA, EC 4.3.1.1) resulted in multi-enzyme reaction cascades and, thus, augmentation of the substrate spectrum of the sensors. Electrochemical measurements were carried out in presence of the cofactor β-nicotinamide adenine dinucleotide (NAD+) and the redox mediator hexacyanoferrate (III) (HCFIII). The amperometric detection is mediated by oxidation of hexacyanoferrate (II) (HCFII) at an applied potential of + 0.3 V vs. Ag/AgCl. For each biosensor, optimum working conditions were defined by adjustment of cofactor concentrations, buffer pH, and immobilization procedure. Under these improved conditions, amperometric responses were linear up to 3.0 mM for L-malate and fumarate, respectively, with a corresponding sensitivity of 0.7 μA mM-1 (L-malate biosensor) and 0.4 μA mM-1 (fumarate biosensor). The L-aspartate detection system displayed a linear range of 1.0-10.0 mM with a sensitivity of 0.09 μA mM-1. The sensor characteristics suggest that the developed platform provides a promising method for the detection and differentiation of the three substrates.}, language = {en} }