Ein Mikroringresonator als DEP-Elektrode: Biopartikelwechselwirkungen und Integration in die Biosensorik
Biomedizinische Systemtechnik
Zusammenfassung der Projektergebnisse
In the next decades, photonics are predicted to find more important applications in medicine and in the life sciences. This is especially true for silicon-integrated photonics, which in combination with microelectronics will enable extensive miniaturization, as a result of which technologies previously only used in laboratories can be used directly in the field or on patients as a point of care device. Recent progress related to ring resonator-based sensors is mainly due to improvements in fabrications technologies, waveguide/cavity design and read out systems aiming to lower the detectable changes in the refractive index around the waveguide through new detection approaches that surpasses technical noise sources. However, the miniaturization of microtechnology and its integration with microfluidics into so called lab on a chip (LOC) devices offers a large variety of new approaches to improve bio-sensing. For example, via more effective sample delivery systems, small handling volumes and lengths scales, a high degree of parallelization and automation as well as electric manipulation. In this project we have successfully developed a sensor that combines microring resonator-based sensing with dielectrophoresis in order to improve mass transfer of desired analytes. The surface chemistry of the ring resonator was explored and a suitable biofunctionalization strategy based on APTES was identified. A photonic chip that both enable the detection of analytes via microring resonator-based sensing as well as its concentration onto the sensing surface via dielectrophoresis was successfully designed and fabricated. To assist in the design, we performed FEM simulations that predicted a sufficiently generated ∇E2 for interaction with common analytes. Furthermore, a packaging strategy for the sensors was developed in collaboration with Prof Smith at the university of Edinburgh. The designed chip contains wire bonds that have to be protected against fluids and stress, grating couplers that should be accessible to fiber coupling but protected from liquids and the sensing area that should be exposed to the sample solution. As the chip dimensions are only 6 mm2 this was fairly challenging. A solution was developed based on a UV curable biocompatible epoxy resin that may be structured under a photomask to generate 3 cavities (two to enable fiber coupling and one to enable exposing of the sample solution) while protecting the wire bonds. The sample solution was delivered via a PDMS based microfluidic system. The position of the resonance peak of the realized ring resonator was confirmed to be linearly correlated to the refractive index of the environment, confirming its function as a sensor with a sensitivity of 4.9 ±0.03 nm/RIU and a Q factor of approximately 1-1.5x105. Finally, as a proof of principle, the microalgae C. cohni was successfully aligned onto the sensor surface by applying an AC field of 10 MHz and 10 Vpp. Dielectrophoresis has previously been successfully applied to achieve a 1000-fold improved detection efficiency in nanopore sensing and may significantly also increase the sensitivity in microring resonator biosensors as well.The preliminary experiments carried out in the project indicates that the developed sensors may be very useful and have high potential regarding future application in biosensing, for example, pathogen diagnostics through different approaches, such as detection of RNA or whole cells.
Projektbezogene Publikationen (Auswahl)
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Biofunctionalization of a microring resonator via hydrosilylation followed by copper free click chemistry, EnFi 2019 – 12th Engineering of Functional Interfaces, KU Leuwen Belgium, July 2019
A. Henriksson, L. Kasper, C. Schipp, P. Neubauer, M. Birkholz
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Biofunctionalization of a microring resonator via hydrosilylation followed by copper free click chemistry, the 9th International Workshop on Surface Modification for Chemical and Biochemical Sensing, Zelechow, Poland, July 2019
A. Henriksson, L. Kasper, C. Schipp, P. Neubauer, M. Birkholz
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Click Coupling Reactions on Flat and Nanostructured Hydrogen- Passivated Silicon Surfaces. Phys. status solidi (a) 2019, 216, 1800683
Henriksson, A.; Hoffmann, H.
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An Approach to Ring Resonator Biosensing Assisted by Dielectrophoresis: Design, Simulation and Fabrication, Micromachines 2020, 11(11), 954
Henriksson A, Kasper L, Jäger M, Neubauer P, Birkholz M
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„Applying Dielectrophoresis to Improve a Microring Resonator Biosensor Platform“, 6th BioProScale Symposium, 2021, Poster P18, March 29-31 2021, Berlin/Online
Anders Henriksson, Laura Kasper, Matthias Jäger, Peter Neubauer, Mario Birkholz
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„Design, Simulations and Manufacturing of a Microring Resonator Biosensor Assisted by Dielectrophoresis“, 3rd European Biosensor Symposiuim 2021, Poster PS3-03, March 09-12 2021, Wildau/Online
Anders Henriksson, Laura Kasper, Matthias Jäger, Peter Neubauer, Mario Birkholz
