Beliaev Leonid Yu, Stounbjerg Peter Groth, Finco Giovanni, Bunea Ada-Ioana, Malureanu Radu, Lindvold Lars René, Takayama Osamu, Andersen Peter E, Lavrinenko Andrei V
DTU Fotonik-Department of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, Building 345A, DK-2800 Kongens Lyngby, Denmark.
DTU Health-Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 345C, DK-2800 Kongens Lyngby, Denmark.
Nanomaterials (Basel). 2022 May 20;12(10):1748. doi: 10.3390/nano12101748.
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 () and limit of quantification () for the structures. PHCG showed a of 2.1 ng/mL and 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.
高对比度光栅（HCG）是用于无标记检测各种生物标志物的极佳选择，因为它们表现出尖锐且灵敏的光学共振。在这项工作中，我们通过实验展示了基座式高对比度光栅（PHCG）的性能，与传统的HCG相比，其性能有显著提升。发现PHCG在体折射率灵敏度方面提高了11.2%，从传统设计的482 nm/RIU提高到了536 nm/RIU。观察到的共振更窄，从而导致更高的品质因数和优值。通过沉积不同厚度的Al2O3、HfO2和TiO2作为模型分析物层，估计PHCG的表面灵敏度值提高了10.5%。为了评估传感器在溶液中的运行情况，使用抗生物素蛋白作为模型分析物。对于抗生物素蛋白检测，首先对HCG表面进行硅烷化处理，随后用生物素进行功能化，生物素以其选择性结合抗生物素蛋白的能力而闻名。随着每个功能层的添加，观察到一致的红移，并且通过分析不同浓度抗生物素蛋白的光谱位移，可以计算出这些结构的检测限（LOD）和定量限（LOQ）。PHCG的LOD为2.1 ng/mL，LOQ为85 ng/mL，分别显著优于传统HCG获得的3.2 ng/mL和213 ng/mL的值。这些结果表明，所提出的PHCG在生物传感应用中具有巨大潜力，特别是用于检测和定量低浓度分析物。
