Highly sensitive biological detection opens new opportunities for biomolecular sensing. Label-free detection with high-Q microcavities is highly advantageous to perform label-free sensing due to its high sensitivity. We propose to develop a platform for multiplex label-free sensing with microring resonators. Close to the ring, we fabricate nanoscale pores (nanopores) for positioning control. This allows control of biomolecules position by electrophoretic force, without the need of surface immobilisation. Structures are designed to allow for multiplex sensing. The sensitivity is optimised thanks to the microrings properties as well as positioning and properties of the nanopores. Microring resonators are fabricated on a silicon-on-insulator substrate, using standard CMOS processing, allowing for cheap mass fabrication and integration with multiple sensing spots for real-time sensing in a lab on chip format. SOI offers a high refractive index contrast suitable for the fabrication of nanophotonic circuits including micron- and submicron sized optical cavities of very high quality. Solid-state nanopores are fabricated on Si3N4 membranes, using focused ion beam process. We also implement fluidic integration and optical set-up for multiplex measurement of resonant profiles. A tunable light source beam of wavelength l=1.3 micron is coupled in an input waveguide. It is further multiplexed to sense several rings in parallel. Translocation events through the nanopores induce a change of refractive index and therefore of guiding properties which may be measured through resonant response. Our technique allows performing biological sensing without the need of biomolecules immobilisation on a chip substrate. Biological tests are first carried out with DNA ladders for fragment sizing. We will then study potential of our platform for fingerprinting of proteins. It will open new opportunities to diagnosis applications as well as to study analytical measurements in complex systems.
Field of science
- /natural sciences/biological sciences/biochemistry/biomolecules/proteins
- /natural sciences/biological sciences/biochemistry/biomolecules
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