@inproceedings{HauslerGensleinRothetal., author = {Hausler, Peter and Genslein, Christa and Roth, Carina and Vitzthumecker, Thomas and Hirsch, Thomas and Bierl, Rudolf}, title = {Miniaturized Surface Plasmon Resonance based Sensor System}, series = {Proceedings of the 6th International Conference on Photonics, Optics and Laser Technology - PHOTOPTICS, Funchal, Madeira, Portugal}, booktitle = {Proceedings of the 6th International Conference on Photonics, Optics and Laser Technology - PHOTOPTICS, Funchal, Madeira, Portugal}, publisher = {SciTePress}, isbn = {978-989-758-286-8}, doi = {10.5220/0006555400630066}, pages = {63 -- 66}, abstract = {We describe the miniaturization of the Surface Plasmon Resonance (SPR) technology which mainly finds its applications in pharmaceutical screening and biotechnology so far. SPR spectroscopy is a label-free, non-destructive and highly sensitive measurement principle detecting changes in the refractive index in striking distance to a gold surface. A transfer of this technology to a miniaturized sensor will broaden the range of possible applications. A promising feature which is included in the miniaturized system is the angle-dependent recording of the SPR signals without moving parts. Commercial SPR assays are mainly working with a small number of sensing spots. In contrast, the SPR imaging system shown here will allow to use an array of many sensing spots. In combination with chemical receptors designed as an artificial nose, the simultaneous detection of many analytes is envisioned for future applications.}, language = {en} } @inproceedings{HauslerRothAumeretal., author = {Hausler, Peter and Roth, Carina and Aumer, F. and Vitzthumecker, Thomas and Genslein, Christa and Hirsch, Thomas and Bierl, Rudolf}, title = {Miniaturisiertes Sensorsystem zur Oberfl{\"a}chenplasmonenresonanzspektroskopie}, series = {118. Jahrestagung der deutschen Gesellschaft f{\"u}r angewandte Optik (DGaO), 6.-10. Juni 2017, Dresden}, booktitle = {118. Jahrestagung der deutschen Gesellschaft f{\"u}r angewandte Optik (DGaO), 6.-10. Juni 2017, Dresden}, abstract = {Die Oberfl{\"a}chenplasmonenresonanzspektroskopie (SPR) wird aufgrund ihrer Vorz{\"u}ge der zerst{\"o}rungs- und markierungsfreien Messung, sowie der hohen Sensitivit{\"a}t sehr erfolgreich im Labormaßstab eingesetzt. Aufgrund der hohen Kosten geschieht dies bislang haupts{\"a}chlich in der Bioanalytik und dem Wirkstoffscreening. Gezeigt wird ein Ansatz, mit dem diese Technologie auf ein ultrakompaktes, kosteng{\"u}nstiges Sensorsystem {\"u}bertragen wird, welches in der Lage ist, hoch-sensitiv {\"A}nderungen im Brechungsindex von 10-6 Einheiten (RIU) zu detektieren. F{\"u}r Wasser bewirkt eine Temperaturschwankung von 1 K bereits eine {\"A}nderung von 1 mRIU. Daher wird durch ein integriertes Referenzsystem, sowie die Miniaturisierung erreicht, dass das System gegen{\"u}ber Temperaturschwankungen, weitestgehend stabil ist. In dem MOEMS wird anstatt der konventionellen 1-Punkt bzw. 2-Punkt Messung ein bildgebendes Verfahren angewendet. Die Sensorfl{\"a}che von 15 x 15 mm wird dabei mit einem handels{\"u}blichen 4 Mio. Pixel CMOS Sensor ausgewertet. Um verl{\"a}ssliche Datenpunkte zu erhalten ben{\"o}tigt man eine Fl{\"a}che von 10 x 10 Pixel. Demzufolge k{\"o}nnen auf dem Sensor theoretisch bis zu 40.000 Sensorspots parallel ausgewertet werden.}, language = {de} } @article{GensleinHauslerKirchneretal., author = {Genslein, Christa and Hausler, Peter and Kirchner, Eva-Maria and Bierl, Rudolf and Baeumner, Antje J. and Hirsch, Thomas}, title = {Graphene-enhanced plasmonic nanohole arrays for environmental sensing in aqueous samples}, series = {Beilstein Journal of Nanotechnology}, journal = {Beilstein Journal of Nanotechnology}, number = {7}, doi = {10.3762/bjnano.7.150}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:355-epub-398623}, pages = {1564 -- 1573}, abstract = {The label-free nature of surface plasmon resonance techniques (SPR) enables a fast, specific, and sensitive analysis of molecular interactions. However, detection of highly diluted concentrations and small molecules is still challenging. It is shown here that in contrast to continuous gold films, gold nanohole arrays can significantly improve the performance of SPR devices in angle-dependent measurement mode, as a signal amplification arises from localized surface plasmons at the nanostructures. This leads consequently to an increased sensing capability of molecules bound to the nanohole array surface. Furthermore, a reduced graphene oxide (rGO) sensor surface was layered over the nanohole array. Reduced graphene oxide is a 2D nanomaterial consisting of sp2-hybridized carbon atoms and is an attractive receptor surface for SPR as it omits any bulk phase and therefore allows fast response times. In fact, it was found that nanohole arrays demonstrated a higher shift in the resonance angle of 250-380\% compared to a continuous gold film. At the same time the nanohole array structure as characterized by its diameter-to-periodicity ratio had minimal influence on the binding capacity of the sensor surface. As a simple and environmentally highly relevant model, binding of the plasticizer diethyl phthalate (DEP) via π-stacking was monitored on the rGO gold nanohole array realizing a limit of detection of as low as 20 nM. The concentration-dependent signal change was studied with the best performing rGO-modified nanohole arrays. Compared to continuous gold films a diameter-to-periodicity ratio (D/P) of 0.43 lead to a 12-fold signal enhancement. Finally, the effect of environmental waters on the sensor was evaluated using samples from sea, lake and river waters spiked with analytically relevant amounts of DEP during which significant changes in the SPR signal are observed. It is expected that this concept can be successfully transferred to enhance the sensitivity in SPR sensors.}, language = {en} } @inproceedings{HauslerHollerHirschetal., author = {Hausler, Peter and Holler, Sven and Hirsch, Thomas and Bierl, Rudolf}, title = {High integrated miniaturized sensor based on Surface Plasmon Resonance}, series = {International Biosensor Conference, 11th Workshop on Biosensors \& Bioanalytical Microtechniques in Environmental, Food \& Clinical Analysis, BBMEC 11, 26.-30. September 2015, Regensburg, Germany}, booktitle = {International Biosensor Conference, 11th Workshop on Biosensors \& Bioanalytical Microtechniques in Environmental, Food \& Clinical Analysis, BBMEC 11, 26.-30. September 2015, Regensburg, Germany}, language = {en} } @article{GensleinHauslerKirchneretal., author = {Genslein, Christa and Hausler, Peter and Kirchner, Eva-Maria and Bierl, Rudolf and Baeumner, Antje J. and Hirsch, Thomas}, title = {Graphene-enhanced plasmonic nanohole arrays for environmental sensing in aqueous samples}, series = {Beilstein Journal of Nanotechnology}, volume = {7}, journal = {Beilstein Journal of Nanotechnology}, publisher = {Beilstein-Institut}, doi = {10.3762/bjnano.7.150}, pages = {1564 -- 1573}, abstract = {The label-free nature of surface plasmon resonance techniques (SPR) enables a fast, specific, and sensitive analysis of molecular interactions. However, detection of highly diluted concentrations and small molecules is still challenging. It is shown here that in contrast to continuous gold films, gold nanohole arrays can significantly improve the performance of SPR devices in angle-dependent measurement mode, as a signal amplification arises from localized surface plasmons at the nanostructures. This leads consequently to an increased sensing capability of molecules bound to the nanohole array surface. Furthermore, a reduced graphene oxide (rGO) sensor surface was layered over the nanohole array. Reduced graphene oxide is a 2D nanomaterial consisting of sp2-hybridized carbon atoms and is an attractive receptor surface for SPR as it omits any bulk phase and therefore allows fast response times. In fact, it was found that nanohole arrays demonstrated a higher shift in the resonance angle of 250-380\% compared to a continuous gold film. At the same time the nanohole array structure as characterized by its diameter-to-periodicity ratio had minimal influence on the binding capacity of the sensor surface. As a simple and environmentally highly relevant model, binding of the plasticizer diethyl phthalate (DEP) via π-stacking was monitored on the rGO gold nanohole array realizing a limit of detection of as low as 20 nM. The concentration-dependent signal change was studied with the best performing rGO-modified nanohole arrays. Compared to continuous gold films a diameter-to-periodicity ratio (D/P) of 0.43 lead to a 12-fold signal enhancement. Finally, the effect of environmental waters on the sensor was evaluated using samples from sea, lake and river waters spiked with analytically relevant amounts of DEP during which significant changes in the SPR signal are observed. It is expected that this concept can be successfully transferred to enhance the sensitivity in SPR sensors.}, language = {en} } @inproceedings{HauslerFischerWunderlichetal., author = {Hausler, Peter and Fischer, Johannes and Wunderlich, Lukas and Recum, Patrick and Peller, Sebastian and Hirsch, Thomas and Bierl, Rudolf}, title = {Miniaturisierte Sensoren basierend auf Oberfl{\"a}chenplasmonenresonanz, Chancen und Herausforderungen}, series = {DGaO-Proceedings 2021}, booktitle = {DGaO-Proceedings 2021}, publisher = {Dt. Gesellschaft f{\"u}r angewandte Optik}, address = {Erlangen-N{\"u}rnberg}, abstract = {Derzeit gibt es zahlreiche Bereiche, wie Umwelt Monitoring und zivile Infrastruktur in denen geeignete Sensoren f{\"u}r die {\"U}berwachung der Systeme fehlen. SPR-basierte Sensoren haben das Potential diese L{\"u}cke zu schließen. Um f{\"u}r den Einsatz in der Umwelt tauglich zu werden, m{\"u}ssen die Sensoren noch robuster werden. Hier wird eine m{\"o}gliche L{\"o}sung gezeigt.}, language = {de} } @inproceedings{HauslerGensleinRothetal., author = {Hausler, Peter and Genslein, Christa and Roth, Carina and Hirsch, Thomas and Bierl, Rudolf}, title = {Mikro-Opto-Elektro-Mechanisches Sensorsystem zur Oberfl{\"a}chenplasmonenresonanzspektroskopie}, series = {MikroSystemTechnik Kongress 2017 : MEMS, Mikroelektronik, Systeme 23.-25. Oktober 2017 in M{\"u}nchen}, booktitle = {MikroSystemTechnik Kongress 2017 : MEMS, Mikroelektronik, Systeme 23.-25. Oktober 2017 in M{\"u}nchen}, number = {CD-ROM}, publisher = {VDE-Verlag}, address = {Berlin}, isbn = {978-3-8007-4491-6}, pages = {645 -- 647}, abstract = {Gezeigt wird die Miniaturisierung eines Messsystems f{\"u}r Oberfl{\"a}chenplasmonenresonanzspektroskopie (SPR), einer markierungs-, sowie zerst{\"o}rungsfreien als auch hoch sensitiven Technologie. Aufgrund der hohen Kosten klassischer SPR-Ger{\"a}te wird sie bisher jedoch vornehmlich in der Bio- und Medizintechnik eingesetzt. Das Messprinzip erm{\"o}glicht die Erfassung von Brechungsindex{\"a}nderungen nahe einer Oberfl{\"a}che. Der Transfer dieser Technologie von Laborger{\"a}ten hin zu einem miniaturisierten Sensorsystem senkt die Kosten, macht das System robuster und erm{\"o}glicht so ein wesentlich breiteres Anwendungsspektrum. Ein sehr vielversprechendes Merkmal des hier vorgestellten Systems ist die M{\"o}glichkeit den SPR-Effekt winkelabh{\"a}ngig zur Lichtquelle ohne bewegliche Bauteile zu verfolgen. The miniaturization of Surface Plasmon Resonance (SPR) technology, which mainly finds its applications in pharmaceutical screening and biotechnology so far, is described. SPR spectroscopy is a label-free, non destructive and highly sensitive measurement principle which is capable of detecting changes in the refractive index in striking distance to a gold surface. A transfer of this technology to a miniaturized sensor will broaden the range of possible applications. A promising feature which is included in the miniaturized system is the angle-dependent recording of the SPR signals without moving parts.}, language = {de} } @article{WunderlichHauslerMaerkletal., author = {Wunderlich, Lukas and Hausler, Peter and Maerkl, Susanne and Bierl, Rudolf and Hirsch, Thomas}, title = {Nanoparticle Determination in Water by LED-Excited Surface Plasmon Resonance Imaging}, series = {Chemosensors}, volume = {9}, journal = {Chemosensors}, number = {7}, publisher = {MDPI}, issn = {2227-9040}, doi = {10.3390/chemosensors9070175}, pages = {1 -- 9}, abstract = {The increasing popularity of nanoparticles in many applications has led to the fact that these persistent materials pollute our environment and threaten our health. An online sensor system for monitoring the presence of nanoparticles in fresh water would be highly desired. We propose a label-free sensor based on SPR imaging. The sensitivity was enhanced by a factor of about 100 by improving the detector by using a high-resolution camera. This revealed that the light source also needed to be improved by using LED excitation instead of a laser light source. As a receptor, different self-assembled monolayers have been screened. It can be seen that the nanoparticle receptor interaction is of a complex nature. The best system when taking sensitivity as well as reversibility into account is given by a dodecanethiol monolayer on the gold sensor surface. Lanthanide-doped nanoparticles, 29 nm in diameter and with a similar refractive index to the most common silica nanoparticles were detected in water down to 1.5 mu g mL(-1). The sensor can be fully regenerated within one hour without the need for any washing buffer. This sensing concept is expected to be easily adapted for the detection of nanoparticles of different size, shape, and composition, and upon miniaturization, suitable for long-term applications to monitor the quality of water.}, language = {en} } @inproceedings{HauslerHollerHirschetal., author = {Hausler, Peter and Holler, Sven and Hirsch, Thomas and Bierl, Rudolf}, title = {Miniaturisierte Oberfl{\"a}chenplasmonenresonanz Sensorplattform}, series = {MEMS, Mikroelektronik, Systeme, MikroSystemTechnik Kongress 2015, 26.- 28. Oktober 2015, Karlsruhe, proceedings}, booktitle = {MEMS, Mikroelektronik, Systeme, MikroSystemTechnik Kongress 2015, 26.- 28. Oktober 2015, Karlsruhe, proceedings}, publisher = {VDE Verlag}, address = {Berlin}, isbn = {978-3-8007-4100-7}, language = {de} } @inproceedings{HauslerWunderlichFischeretal., author = {Hausler, Peter and Wunderlich, Lukas and Fischer, Johannes and Pfab, Christina and Heckscher, Simon and Hirsch, Thomas and Bierl, Rudolf}, title = {Surface plasmon resonance imaging for detection of drug metabolites in water}, series = {Proceedings of SPIE, Optical Sensors 2019, 1 - 4 April 2019, Prague, Czech Republic}, volume = {Vol. 11028}, booktitle = {Proceedings of SPIE, Optical Sensors 2019, 1 - 4 April 2019, Prague, Czech Republic}, issn = {0277-786X}, doi = {10.1117/12.2522324}, pages = {11}, abstract = {The analysis of surface water, groundwater, drinking water as well as sewage is important to get information about the contamination of the water cycle. Currently, these time-consuming investigations require special equipment, like for example hyphenated mass spectrometry. Surface plasmon resonance (SPR) is a faster alternative as it is highly sensitive to changes in the dielectric medium next to a thin metal layer and makes it a quasi-universal detector. Therefore, and due to the labelfree nature, SPR is a widely used sensing tool for real-time monitoring of molecular interactions of various analytes. SPR imaging (SPRi) has several advantages to standard surface plasmon resonance, as it allows to observe many analytes in parallel as well as the integration of referencing technologies. However, the homogenous illumination of a large area (several millimeters) with a small light source is challenging and demands new approaches. Allopurinol, a drug used to lower the blood concentration of urate and hence decrease the affection of gout, gets metabolized to oxipurinol in the body and dropped out almost entirely by urinary excretion. After wastewater treatment, concentrations of oxipurinol up to 21.7 μg•L-1 are detected. Further tracking of oxipurinol in the urban water cycle showed its presence in rivers and streams or even in groundwater. Therefore, the high biological stability of oxipurinol allows this molecule to be used as a marker for domestic wastewater in the environment. For the detection of oxipurinol by SPR graphene was used as receptive layer, as the analyte can bind via π-stacking to this surface. An SPRi technique was developed and compared to conventional SPR system for the detection of oxipurinol.}, language = {en} } @inproceedings{GensleinHauserKirchneretal., author = {Genslein, Christa and Hauser, Peter and Kirchner, Eva-Maria and Bierl, Rudolf and Baeumner, Antje J. and Hirsch, Thomas}, title = {Detection of small molecules with surface plasmon resonance by synergistic plasmonic effects of nanostructured surfaces and graphene}, series = {SPIE Proceedings, Plasmonics in Biology and Medicine XIV, 2017, San Francisco, California}, volume = {10080}, booktitle = {SPIE Proceedings, Plasmonics in Biology and Medicine XIV, 2017, San Francisco, California}, number = {1008001F}, doi = {10.1117/12.2252256}, abstract = {Surface plasmon resonance depends on the dielectric medium at the vicinity and makes it a quasi-universal detector. Therefore, and due to the label-free nature, SPR is a widely used sensing tool for real-time monitoring molecular interactions of various analytes. However, detection of highly diluted analytes and small molecules (< 400 Da) is still challenging. Gold nanohole arrays provide plasmonic hotspots with improved surface sensitivity and 2D carbon nanomaterials enable binding near the surface. Both effects together are promising in the development of SPR sensors for the efficient determination of small molecules. Graphene is known for efficient binding of molecules with delocalized aromatic π-systems. Additionally, the electromagnetic field is locally enhanced and modulated by the interaction of graphene photonics with the plasmonics of metal nanostructures. The advantages of chemical vapor deposition (CVD) graphene over reduced graphene oxide (rGO) is illustrated by a proof of concept study. In comparison to substrates consisting of a continuous film the surface sensitivity is enhanced for a nanohole arrays and further improved for CVD graphene functionalization in contrast to rGO. The feasibility of the sensor was demonstrated for the detection of adenine down to a concentration of 0.9 μM.}, language = {en} } @article{JobstRecumEcijaArenasetal.2023, author = {Jobst, Simon and Recum, Patrick and {\´E}cija-Arenas, {\´A}ngela and Moser, Elisabeth and Bierl, Rudolf and Hirsch, Thomas}, title = {Semi-Selective Array for the Classification of Purines with Surface Plasmon Resonance Imaging and Deep Learning Data Analysis}, series = {ACS sensors}, volume = {8}, journal = {ACS sensors}, number = {9}, publisher = {American Chemical Society}, doi = {10.1021/acssensors.3c01114}, pages = {3530 -- 3537}, year = {2023}, abstract = {In process analytics or environmental monitoring, the real-time recording of the composition of complex samples over a long period of time presents a great challenge. Promising solutions are label-free techniques such as surface plasmon resonance (SPR) spectroscopy. They are, however, often limited due to poor reversibility of analyte binding. In this work, we introduce how SPR imaging in combination with a semi-selective functional surface and smart data analysis can identify small and chemically similar molecules. Our sensor uses individual functional spots made from different ratios of graphene oxide and reduced graphene oxide, which generate a unique signal pattern depending on the analyte due to different binding affinities. These patterns allow four purine bases to be distinguished after classification using a convolutional neural network (CNN) at concentrations as low as 50 μM. The validation and test set classification accuracies were constant across multiple measurements on multiple sensors using a standard CNN, which promises to serve as a future method for developing online sensors in complex mixtures.}, language = {en} }