A Multiplexed Magneto-Assay Platform with Dye-Encoded Polyelectrolyte Microcapsules

• Applicant: Dr. Metin Kayci
• Subject Area: Synthesis and Properties of Functional Materials ; Polymeric and Biogenic Materials and Derived Composites ; Polymer Materials
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 506083804

This proposal aims to develop encoded microsensor platforms for multiplexed sensing of biomolecules with integrated bioreceptors targeting specific analytes in complex biological samples, and Nitrogen-Vacancy (NV) quantum centers-based measurement system that detects magnetic nanotag (MNT) conjugated probe molecules through the optically detected magnetic resonance (ODMR) spectrum. It presents design methodologies for the synthesis of polyelectrolyte microcapsules, which transduce the binding events occurring on their surface into magnetic dipoles, and the complementary experimental setup to extract the effective magnetic field exerted on the NV quantum centers.Encoded microcapsules will be investigated for sensing applications where the detection is not limited to imaging a planar surface but rather extended to a three-dimensional reservoir. While a stationary sensor design can only allow the detection of a local layer close to the sensor surface, with this strategy, floating microstructures will enable an active sensing mechanism in the target sample. First, we will develop polyelectrolyte microcapsules with a multilayer architecture that allows the incorporation of fluorescent dyes for multiplexing and serves as a magneto-assay platform that immobilizes MNTs on their surface upon target interactions, thereby enabling parallel measurements of target molecules. Based on our recent work (PNAS 118, 51 (2021)), we will then use our bulk diamond-based magnetic imaging system to perform magnetic profile measurements on these dye-encoded microstructures to detect target molecules. Second, with the integration of fluorescent nanodiamonds (FNDs) into the outer layer of the developed polyelectrolyte microcapsules, we will eliminate the need for chip-scale diamond measurements and develop miniaturized microsensor systems that provide a direct ODMR signal through the embedded NV quantum centers. The ultimate goal will be to establish magnetic nanotag (MNT)-based aptasensor platforms and employ them to detect thrombin molecules, which is crucial for the homeostasis process and plays a critical role in life-threatening thrombosis associated with numerous diseases such as atherosclerosis and stroke. One main step towards this goal will be the detection of DNA hybridization events with a low limit of detection and high selectivity for the target DNA molecules. Further engineering of the hybrid architecture of microcapsules will be another focus for the development of multifunctional building blocks. For example, therapeutics or signaling molecules incorporated into the microcapsule architecture can provide delivery vehicles for a controlled release mechanism, while the embedded NV quantum centers can be used for the simultaneous detection of specific targets. The realization of such a system in a microfluidic-based complementary detection platform will pave the way for low-volume and cost-effective manipulation and analysis of biological samples.

• DFG Programme: Research Grants