| Autor: |
Beliaev LY; DTU Fotonik-Department of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, Building 345A, DK-2800 Kongens Lyngby, Denmark., Stounbjerg PG; DTU Health-Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 345C, DK-2800 Kongens Lyngby, Denmark., Finco G; DTU Fotonik-Department of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, Building 345A, DK-2800 Kongens Lyngby, Denmark.; Optical Nanomaterial Group, Department of Physics, Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, HPT D5, 8093 Zürich, Switzerland., Bunea AI; DTU Nanolab-National Centre for Nano Fabrication and Characterization, Technical University of Denmark, Ørsteds Plads, Building 347, DK-2800 Kongens Lyngby, Denmark., Malureanu R; DTU Fotonik-Department of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, Building 345A, DK-2800 Kongens Lyngby, Denmark., Lindvold LR; DTU Health-Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 345C, DK-2800 Kongens Lyngby, Denmark., Takayama O; DTU Fotonik-Department of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, Building 345A, DK-2800 Kongens Lyngby, Denmark., Andersen PE; DTU Health-Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 345C, DK-2800 Kongens Lyngby, Denmark., Lavrinenko AV; DTU Fotonik-Department of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, Building 345A, DK-2800 Kongens Lyngby, Denmark. |
| Abstrakt: |
High-contrast gratings (HCG) are an excellent candidate for label-free detection of various kinds of biomarkers because they exhibit sharp and sensitive optical resonances. In this work, we experimentally show the performance of pedestal HCG (PHCG), which is significantly enhanced in comparison with that of conventional HCG. PCHGs were found to provide a 11.2% improvement in bulk refractive index sensitivity, from 482 nm/RIU for the conventional design to 536 nm/RIU. The observed resonance was narrower, resulting in a higher Q-factor and figure of merit. By depositing Al2O3, HfO2, and TiO2 of different thicknesses as model analyte layers, surface sensitivity values were estimated to be 10.5% better for PHCG. To evaluate the operation of the sensor in solution, avidin was employed as a model analyte. For avidin detection, the surface of the HCG was first silanized and subsequently functionalized with biotin, which is well known for its ability to bind selectively to avidin. A consistent red shift was observed with the addition of each of the functional layers, and the analysis of the spectral shift for various concentrations of avidin made it possible to calculate the limit of detection ( LoD ) and limit of quantification ( LoQ ) for the structures. PHCG showed a LoD of 2.1 ng/mL and LoQ of 85 ng/mL, significantly better than the values 3.2 ng/mL and 213 ng/mL respectively, obtained with the conventional HCG. These results demonstrate that the proposed PHCG have great potential for biosensing applications, particularly for detecting and quantifying low analyte concentrations. |
