Highly sensitive optical waveguide sensor platform for the multiplexed detection of biochemical analytes

• Applicant: Professor Dr. Bernhard Roth
• Subject Area: Microsystems ; Measurement Systems
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 493687068

The goal of this project is to demonstrate a novel micro- and nanostructured optical sensor platform with a high number (> 100) of spatially separated sensor spots (<100 µm) to enable highly sensitive and specific detection of various biomarkers simultaneously from a minimal amount of sample solution. The project addresses the great demand for integrated, robust and at the same time sensitive sensor concepts for the multiplex detection of different substances in environment, technology, life sciences and medicine and aims to develop a powerful alternative concept compared to conventional approaches.The proposed concept combines 3D printing of polymer-optical micro- and nanostructures as the basis of the platform with optical frequency domain reflectometry (OFDR) for highly sensitive and fast signal evaluation. For this purpose, light coupled into the sensor platform will be reflected on tailored micro- and nanostructured waveguide elements (Bragg structures as sensor spots) and detected by coherent measurement. Since the amplitudes and phases of the partial reflections depend on the surrounding refractive index at the reflection point, the refractive index profile along the optical waveguide structures can be determined with high spatial resolution. For the highly specific detection of different target substances, functionalization with spatially separated bio-receptors will be implemented. The local refractive index changes induced by binding events, which lead to spatially encoded amplitude and phase changes, will be decoded by a suitable signal processing algorithm, so that parallel detection of a large number of different substances and thus highly parallelized biosensing are possible. On the one hand, (i) a high spatial resolution of the platform and thus multiplexing as well as (ii) high sensitivity through precisely manufactured micro- and nanooptical structures and the OFDR unit need to be demonstrated, on the other hand (iii) high specificity through suitable functionalization concepts need to be realized. The central scientific challenges for the funding period proposed here (36 months) are: (i) the modeling and production of the micro- and nanooptical polymer waveguide structures, (ii) the realization and implementation of the OFDR unit and the evaluation algorithm, and (iii) the functional verification as highly sensitive and selective biosensor platform by using a mouse IgG/anti-mouse IgG model system and first simple microfluidics (target parameters: see work program). In a possible second funding period, the integrated microfluidics and miniaturization of the system towards a mobile platform and the further development of the fabrication towards high-throughput-compatible production will be addressed.

• DFG Programme: Research Grants
• Major Instrumentation: Nano-Plotter
• Instrumentation Group: 1060 Dilutoren, Pipettiergeräte, Probennehmer