title: Alkanethiol-functionalized terahertz metamaterial as label-free, highly-sensitive and specific biosensor.
abstract: Specific biorecognition is essential for many biological processes, for which highly sensitive and label-free biosensors are strongly demanded. The recently developed metamaterials are a potential choice for biosensing due to their exotic properties. In the current work, a label-free and specific sensor for streptavidin-agarose (SA) was fabricated based on terahertz metamaterial functionlized by octadecanthiols and biotins. Both low and high frequency resonant modes from the metamaterials are found applicable for the detection of SA, and a redshift up to 6.76 GHz for the high frequency mode was measured in the undiluted commercial solution. The low frequency mode is attributed to inductor-capacitor (LC) oscillation, while the high frequency mode originates from the plasmonic dipole oscillator, both of which are highly sensitive to the micro-environment change. Adsorption of SA of different concentrations causes different redshifts, and the replacement of high refractive-index substrate with low refractive-index substrate can efficiently promote the sensitivity, well agreeing with the numerical simulation. Moreover, for a particular biomolecule, the sensitivity can be further improved by optimizing the metamaterial design. This method might be very helpful for desirable biorecognition in biology, medicine, and drug industry.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Wu
authors.forename: Baogang
authors.initials: B
authors.lastname: Quan
authors.forename: Xuecong
authors.initials: X
authors.lastname: Pan
authors.forename: Xinlong
authors.initials: X
authors.lastname: Xu
authors.forename: Xinchao
authors.initials: X
authors.lastname: Lu
authors.forename: Changzhi
authors.initials: C
authors.lastname: Gu
authors.forename: Li
authors.initials: L
authors.lastname: Wang
mesh_terms: D000473:Alkanes / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification*; D015374:Biosensing Techniques / Q000379:methods*; D001710:Biotin / Q000737:chemistry; D012031:Refractometry; D012685:Sepharose / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification; D013229:Stearic Acids / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry; D020349:Surface Plasmon Resonance; D055053:Terahertz Radiation
chemical_list: D000473:Alkanes; D001426:Bacterial Proteins; D013229:Stearic Acids; D013438:Sulfhydryl Compounds; C049538:streptavidin-agarose; C031183:stearic acid; D001710:Biotin; D012685:Sepharose