We report that single-stranded deoxyribonucleic acids (ssDNAs) at very low concentrations can be detected using graphene-combined nano-slot-based terahertz (THz) resonance. A combination of the resonant structure and tuned electro-optical properties of graphene can provide unprecedentedly sensitive biomolecule sensing even using very low energy THz photons, overcoming the huge scale difference of 10,000:1 between the wavelength and the size of the ssDNAs. Ultrahigh sensitivity is obtained by the significant increase in the absorption cross-section of the graphene sheet with the targeted biomolecules, induced by strong THz field enhancement at the resonance frequency inside the slots. Clearly distinguishable THz optical signals were observed between different species of ssDNAs even at the nano-mole level and analyzed quantitatively in terms of the electro-optical properties of the suspended graphene layer modified by the attached ssDNAs without any molecular-specific labeling for the THz regime. Quantitative analysis of ssDNA molecule adsorption was carried based on the change in conductivity using a theoretical THz transmission model.
Bibliographical noteFunding Information:
This research was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (NRF-2016R1A2B2010858 and NRF-2017R1A6A3A11034292 and the Global Frontier Program CAMM-2019M3A6B3030638 and CAMM-2014M3A6B3063710), and KIST intramural grants (2E29490 and 2V06780).
This research was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (NRF- 2016R1A2B2010858 and NRF - 2017R1A6A3A11034292 and the Global Frontier Program CAMM - 2019M3A6B3030638 and CAMM - 2014M3A6B3063710 ), and KIST intramural grants ( 2E29490 and 2V06780 ).
© 2020 The Author(s)
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering
- Materials Chemistry