Pixeled metasurface for multiwavelength detection of vitamin D

Nanophotonics

article

Valentina Di Meo¹  Alessio Crescitelli¹  Massimo Moccia²  Annamaria Sandomenico³  Angela M. Cusano⁴  Marianna Portaccio⁵  Maria Lepore⁵  Vincenzo Galdi²  Emanuela Esposito¹ 

[1] Institute of Applied Sciences and Intelligent Systems Unit of Naples, National Research Council;Fields & Waves Lab, Department of Engineering, University of Sannio;Institute of Biostructure and Bioimaging, National Research Council;CeRICT scrl;Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”

关键词: biochemical sensing;    nanostructures;    plasmonic metasurfaces;    SEIRA effect;   

DOI  :  10.1515/nanoph-2020-0103

学科分类：社会科学、人文和艺术（综合）

来源: De Gruyter

【 摘 要 】

The steadily increasing demand for accurate analysis of vitamin D level, via measurement of its best general marker, 25-hydroxyvitamin D (25(OH)D), pushes for the development of novel automated assays capable of working at very low concentrations. Here, we propose a plasmonic biosensor of 25(OH)D3 (calcifediol) based on surface-enhanced infrared absorption spectroscopy, which exploits the resonant coupling between plasmonic nanoantennas and vibrational excitation of small molecules. Specifically, our proposed platform features a large-area (several mm 2 ) metasurface made of gold nanoantennas fabricated on a silicon substrate, comprising different macroregions (“pixels”) of area 500 × 500 µm 2 . In each pixel, the nanoantenna geometrical parameters are tuned so as to support localized surface plasmon resonances (and hence large field enhancements at the nanoscale) within different regions of the infrared spectrum. As a result, a single chip is capable of performing analysis from the region of functional groups to that of fingerprint. Two different designs are fabricated via electron beam lithography, functionalized with a correlated antibody for the detection of 25(OH)D3, and characterized via Fourier-transform infrared spectroscopy. Our experiments demonstrate the capability to detect a concentration as low as 86 pmol/L, and an amount of immobilized small molecules of 25(OH)D3 monohydrate (molecular weight: 418.65 g/mol) as low as 4.31 amol over an area of 100 × 100 µm 2 .

【 授权许可】

CC BY