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Buch ; Online ; Dissertation / Habilitation: <dc:title>Metabolic monitoring in dynamic 3D cell culture systems</dc:title>

Dornhof, Johannes [Verfasser] / Urban, Gerald A. [Akademischer Betreuer] / Urban, Gerald A. / Rapp, Bastian E.

2024

Schlagwörter	Medizin, Gesundheit ; Medicine, Health
Thema/Rubrik (Code)	sg610
Sprache	Englisch
Verlag	Universität
Erscheinungsort	Freiburg
Dokumenttyp	Buch ; Online ; Dissertation / Habilitation
Datenquelle	Digitale Dissertationen im Internet

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Artikel ; Online: Electrochemical Methods in the Cloud: FreiStat, an IoT-Enabled Embedded Potentiostat

Bill, David / Jasper, Mark / Weltin, Andreas / Urban, Gerald A. / Rupitsch, Stefan J. / Kieninger, Jochen

Analytical Chemistry. 2023 Aug. 15, v. 95, no. 35 p.13003-13009

2023

Abstract: Embedded potentiostats enable electrochemical measurements in the Internet-of-Things (IoT) or other decentralized applications, such as remote environmental monitoring, electrochemical energy systems, and biomedical point-of-care applications. We report ... ...

Abstract	Embedded potentiostats enable electrochemical measurements in the Internet-of-Things (IoT) or other decentralized applications, such as remote environmental monitoring, electrochemical energy systems, and biomedical point-of-care applications. We report on Freiburg’s Potentiostat (FreiStat) based on the AD5941 potentiostat circuit from Analog Devices, together with custom firmware, as the key to precise and advanced electrochemical methods. We demonstrated its analytical performance by various cyclic voltammetry measurements, advanced techniques such as differential pulse voltammetry, and a lactate biosensor measurement with currents in the nA range and a resolution of 54 pA. The FreiStat yielded analytical results comparable to benchtop devices and outperformed current commercial embedded potentiostats at significantly lower cost, smaller size, and lower power consumption. Decentralized corrosion analysis by a Tafel plot using the IBM Cloud showed its applicability in a typical IoT scenario. The developed open-source software framework facilitates the integration of electrochemical instrumentation into applications utilizing machine learning and other artificial intelligence. Together with the affordable and highly capable embedded potentiostat, our approach can leverage analytical chemistry toward increasingly important, more widespread and decentralized applications.
Schlagwörter	analytical chemistry ; artificial intelligence ; biosensors ; computer software ; corrosion ; electrochemistry ; energy ; energy use and consumption ; instrumentation ; lactic acid ; point-of-care systems ; voltammetry
Sprache	Englisch
Erscheinungsverlauf	2023-0815
Umfang	p. 13003-13009.
Erscheinungsort	American Chemical Society
Dokumenttyp	Artikel ; Online
ZDB-ID	1508-8
ISSN	1520-6882 ; 0003-2700
ISSN (online)	1520-6882
ISSN	0003-2700
DOI	10.1021/acs.analchem.3c02114
Datenquelle	NAL Katalog (AGRICOLA)

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Artikel ; Online: In situ stability monitoring of platinum thin-film electrodes for neural interfaces in the presence of proteins.

Doering, Moritz / Kieninger, Jochen / Urban, Gerald A / Weltin, Andreas

Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

2022 Band 2022, Seite(n) 1577–1580

Abstract: The long-term stability of platinum electrodes is a key factor that determines the life-time of biomedical devices, such as implanted neural interfaces like brain stimulation or recording electrodes, cochlear implants, and biosensors. The downsizing of ... ...

Abstract	The long-term stability of platinum electrodes is a key factor that determines the life-time of biomedical devices, such as implanted neural interfaces like brain stimulation or recording electrodes, cochlear implants, and biosensors. The downsizing of such devices relies on the usage of microfabricated thin-film electrodes. In order to determine and investigate the causal degradation processes for platinum electrodes, it is essential to use potential-controlled experiments, which allow selectable polarization of the electrode without exceeding the water stability window boundaries. Therefore, the surface processes and redox reactions occurring at the electrode are known at all times. In this study, we present the continuous in situ monitoring of platinum-based thin-film electrodes along their complete life cycle in neutral pH with and without the presence of proteins. The usage of chronoamperometry for electrode aging, monitoring of surface processes and the tracking of analyte redox processes, together with cyclic voltammetry to determine the complete amount of surface charge, allows a reliable quantification of fundamental degradation processes. We found that platinum dissolution is primarily driven by the formation and removal of Pt oxide. Despite the significantly lowered charge transfer, the presence of proteins did not prevent material loss or increase electrode lifetime. These results should be considered when interpreting results from current-controlled methods as typically used for neural interfaces. Clinical Relevance- All clinically relevant applications of microelectrodes, ranging from cell culture over diagnostics to in vivo use, involve the presence of proteins. Detailed and fundamental insight into electrode stability in the presence of proteins is therefore essential for successful clinical translation of neural interface technologies.
Mesh-Begriff(e)	Biosensing Techniques ; Cochlear Implants ; Microelectrodes ; Platinum ; Stereotaxic Techniques
Chemische Substanzen	Platinum (49DFR088MY)
Sprache	Englisch
Erscheinungsdatum	2022-09-09
Erscheinungsland	United States
Dokumenttyp	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	2694-0604
ISSN (online)	2694-0604
DOI	10.1109/EMBC48229.2022.9871177
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: Electrochemical Methods in the Cloud: FreiStat, an IoT-Enabled Embedded Potentiostat.

Bill, David / Jasper, Mark / Weltin, Andreas / Urban, Gerald A / Rupitsch, Stefan J / Kieninger, Jochen

Analytical chemistry

2023 Band 95, Heft 35, Seite(n) 13003–13009

Abstract	Embedded potentiostats enable electrochemical measurements in the Internet-of-Things (IoT) or other decentralized applications, such as remote environmental monitoring, electrochemical energy systems, and biomedical point-of-care applications. We report on Freiburg's Potentiostat (FreiStat) based on the AD5941 potentiostat circuit from Analog Devices, together with custom firmware, as the key to precise and advanced electrochemical methods. We demonstrated its analytical performance by various cyclic voltammetry measurements, advanced techniques such as differential pulse voltammetry, and a lactate biosensor measurement with currents in the nA range and a resolution of 54 pA. The FreiStat yielded analytical results comparable to benchtop devices and outperformed current commercial embedded potentiostats at significantly lower cost, smaller size, and lower power consumption. Decentralized corrosion analysis by a Tafel plot using the IBM Cloud showed its applicability in a typical IoT scenario. The developed open-source software framework facilitates the integration of electrochemical instrumentation into applications utilizing machine learning and other artificial intelligence. Together with the affordable and highly capable embedded potentiostat, our approach can leverage analytical chemistry toward increasingly important, more widespread and decentralized applications.
Sprache	Englisch
Erscheinungsdatum	2023-08-15
Erscheinungsland	United States
Dokumenttyp	Journal Article
ZDB-ID	1508-8
ISSN	1520-6882 ; 0003-2700
ISSN (online)	1520-6882
ISSN	0003-2700
DOI	10.1021/acs.analchem.3c02114
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: Electrochemical microelectrode degradation monitoring:

Doering, Moritz / Kieninger, Jochen / Urban, Gerald A / Weltin, Andreas

Journal of neural engineering

2022 Band 19, Heft 1

Abstract: ... ...

Abstract	Objective
Mesh-Begriff(e)	Cochlear Implants ; Corrosion ; Electrodes ; Hydrogen-Ion Concentration ; Microelectrodes ; Platinum/chemistry
Chemische Substanzen	Platinum (49DFR088MY)
Sprache	Englisch
Erscheinungsdatum	2022-01-24
Erscheinungsland	England
Dokumenttyp	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2170901-4
ISSN	1741-2552 ; 1741-2560
ISSN (online)	1741-2552
ISSN	1741-2560
DOI	10.1088/1741-2552/ac47da
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: In Situ Performance Monitoring of Electrochemical Oxygen and Hydrogen Peroxide Sensors in an Additively Manufactured Modular Microreactor.

Doering, Moritz / Trinkies, Laura L / Kieninger, Jochen / Kraut, Manfred / Rupitsch, Stefan J / Dittmeyer, Roland / Urban, Gerald A / Weltin, Andreas

ACS omega

2024 Band 9, Heft 17, Seite(n) 19700–19711

Abstract: Miniaturized and microstructured reactors in process engineering are essential for a more decentralized, flexible, sustainable, and resilient chemical production. Modern, additive manufacturing methods for metals enable complex reactor-geometries, ... ...

Abstract	Miniaturized and microstructured reactors in process engineering are essential for a more decentralized, flexible, sustainable, and resilient chemical production. Modern, additive manufacturing methods for metals enable complex reactor-geometries, increased functionality, and faster design iterations, a clear advantage over classical subtractive machining and polymer-based approaches. Integrated microsensors allow online, in situ process monitoring to optimize processes like the direct synthesis of hydrogen peroxide. We developed a modular tube-in-tube membrane reactor fabricated from stainless steel via 3D printing by laser powder bed fusion of metals (PBF-LB/M). The reactor concept enables the spatially separated dosage and resaturation of two gaseous reactants across a membrane into a liquid process medium. Uniquely, we integrated platinum-based electrochemical sensors for the online detection of analytes to reveal the dynamics inside the reactor. An advanced chronoamperometric protocol combined the simultaneous concentration measurement of hydrogen peroxide and oxygen with monitoring of the sensor performance and self-calibration in long-term use. We demonstrated the highly linear and sensitive monitoring of hydrogen peroxide and dissolved oxygen entering the liquid phase through the membrane. Our measurements delivered important real-time insights into the dynamics of the concentrations in the reactor, highlighting the power of electrochemical sensors applied in process engineering. We demonstrated the stable continuous measurement over 1 week and estimated the sensor lifetime for months in the acidic process medium. Our approach combines electrochemical sensors for process monitoring with advanced, additively manufactured stainless steel membrane microreactors, supporting the power of sensor-equipped microreactors as contributors to the paradigm change in process engineering and toward a greener chemistry.
Sprache	Englisch
Erscheinungsdatum	2024-04-16
Erscheinungsland	United States
Dokumenttyp	Journal Article
ISSN	2470-1343
ISSN (online)	2470-1343
DOI	10.1021/acsomega.4c02210
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Buch ; Online ; Dissertation / Habilitation: <dc:title>Einfluss bakteriostatischer/bakterizider Substanzen auf die bakterielle Adhäsion und Biofilmbildung in Echtzeit = Influence of bacteriostatic/bactericidal substances on bacterial adhesion and and biofilm formation in real time</dc:title>

Wieland, Tobias [Verfasser] / Urban, Gerald A. [Akademischer Betreuer] / Urban, Gerald A. / Stieglitz, Thomas

2022

Schlagwörter	Medizin, Gesundheit ; Medicine, Health
Thema/Rubrik (Code)	sg610
Sprache	Deutsch
Verlag	Universität
Erscheinungsort	Freiburg
Dokumenttyp	Buch ; Online ; Dissertation / Habilitation
Datenquelle	Digitale Dissertationen im Internet

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Artikel: Standard cochlear implants as electrochemical sensors: Intracochlear oxygen measurements in vivo

Weltin, Andreas / Kieninger, Jochen / Urban, Gerald A. / Buchholz, Sarah / Arndt, Susan / Rosskothen-Kuhl, Nicole

Biosensors & bioelectronics. 2022 Mar. 01, v. 199

2022

Abstract: Cochlear implants are the most successful neural prostheses worldwide and routinely restore sensorineural hearing loss by direct electrical stimulation of the auditory nerve. Enhancing this standard implant by chemical sensor functionality opens up new ... ...

Abstract	Cochlear implants are the most successful neural prostheses worldwide and routinely restore sensorineural hearing loss by direct electrical stimulation of the auditory nerve. Enhancing this standard implant by chemical sensor functionality opens up new possibilities, ranging from access to the biochemical microenvironment of the implanted electrode array to the long-term study of the electrode status. We developed an electrochemical method to turn the platinum stimulation microelectrodes of cochlear implants into electrochemical sensors. The electrodes showed excellent and stable chemical sensor properties, as demonstrated by in vitro characterizations with combined amperometric and active potentiometric dissolved oxygen and hydrogen peroxide measurements. Linear, stable and highly reproducible sensor responses within the relevant concentration ranges with negligible offset were shown. This approach was successfully applied in vivo in an animal model. Intracochlear oxygen dynamics in rats upon breathing pure oxygen were reproducibly and precisely measured in real-time from the perilymph. At the same time, correct implant placement and its functionality was verified by measurements of electrically evoked auditory brainstem responses with clearly distinguishable peaks. Acute measurements indicated no adverse influence of electrical stimulation on electrochemical measurements and vice versa. Our work is ground-breaking towards advanced implant functionality, future implant lifetime monitoring, and implant-life-long in situ investigation of electrode degradation in cochlear implant patients.
Schlagwörter	animal models ; biosensors ; brain stem ; dissolved oxygen ; electrical treatment ; electrochemistry ; hydrogen peroxide ; microelectrodes ; nerve tissue ; oxygen ; platinum
Sprache	Englisch
Erscheinungsverlauf	2022-0301
Erscheinungsort	Elsevier B.V.
Dokumenttyp	Artikel
ZDB-ID	1011023-9
ISSN	1873-4235 ; 0956-5663
ISSN (online)	1873-4235
ISSN	0956-5663
DOI	10.1016/j.bios.2021.113859
Datenquelle	NAL Katalog (AGRICOLA)

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Artikel ; Online: Electrochemical Microsensor for Microfluidic Glyphosate Monitoring in Water Using MIP-Based Concentrators.

Uka, Besnik / Kieninger, Jochen / Urban, Gerald A / Weltin, Andreas

ACS sensors

2021 Band 6, Heft 7, Seite(n) 2738–2746

Abstract: Glyphosate (GLY) is a broad-spectrum herbicide and is the most used pesticide worldwide. This vast usage has raised strong interest in the ecotoxicological impacts and human risks, with contamination of water being a major concern. Decentralized ... ...

Abstract	Glyphosate (GLY) is a broad-spectrum herbicide and is the most used pesticide worldwide. This vast usage has raised strong interest in the ecotoxicological impacts and human risks, with contamination of water being a major concern. Decentralized analytical techniques for water monitoring are of high importance. In this work, we present a small, low-cost, and time-effective electrochemical, chip-based microfluidic device for direct electrochemical detection of GLY downstream of a molecularly imprinted polymer (MIP) concentrator. We studied the electrochemical behavior of GLY and its metabolite aminomethylphosphonic acid (AMPA) using cyclic voltammetry with noble metal electrodes in acidic, neutral, and basic media. A chronoamperometric sensor protocol was developed for sensitive and selective GLY measurements on gold electrodes. The optimized protocol was transferred to a chip-based microsensor platform for online and real-time detection of GLY in a microfluidic setup. The results in the range from 0 to 50 μM GLY in 0.5 M H
Mesh-Begriff(e)	Glycine/analogs & derivatives ; Humans ; Microfluidics ; Molecular Imprinting ; Molecularly Imprinted Polymers ; Organophosphonates ; Water ; Glyphosate
Chemische Substanzen	Molecularly Imprinted Polymers ; Organophosphonates ; Water (059QF0KO0R) ; aminomethylphosphonic acid (AMPA) (90825O5C1U) ; Glycine (TE7660XO1C)
Sprache	Englisch
Erscheinungsdatum	2021-07-13
Erscheinungsland	United States
Dokumenttyp	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	2379-3694
ISSN (online)	2379-3694
DOI	10.1021/acssensors.1c00884
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: Microfluidic organ-on-chip system for multi-analyte monitoring of metabolites in 3D cell cultures.

Dornhof, Johannes / Kieninger, Jochen / Muralidharan, Harshini / Maurer, Jochen / Urban, Gerald A / Weltin, Andreas

Lab on a chip

2022 Band 22, Heft 2, Seite(n) 225–239

Abstract: Three-dimensional cell cultures using patient-derived stem cells are ... ...

Abstract	Three-dimensional cell cultures using patient-derived stem cells are essential
Mesh-Begriff(e)	Biosensing Techniques ; Cell Culture Techniques, Three Dimensional ; Drug Evaluation, Preclinical ; Energy Metabolism ; Humans ; Lab-On-A-Chip Devices ; Metabolomics/methods ; Microfluidic Analytical Techniques ; Microfluidics/methods ; Organoids
Sprache	Englisch
Erscheinungsdatum	2022-01-18
Erscheinungsland	England
Dokumenttyp	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2056646-3
ISSN	1473-0189 ; 1473-0197
ISSN (online)	1473-0189
ISSN	1473-0197
DOI	10.1039/d1lc00689d
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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