Terahertz Detection of Deoxyribonucleic Bases, Viruses and Nano Particles

A metamaterial composed of diamond-shaped (70 μm X 35 μm) copper patches was designed and used to detect nanoparticles with 0.75-1.1 terahertz transmission spectroscopy. Deoxyribonucleic acid (DNA) bases adenine, thymine, cytosine, and guanine were detected and identified. Cytosine showed 1.7 dB higher absorption around 0.975 THz than the other bases. SARS-CoV-2 infected saliva showed different spectrum and -10 dB higher absorption than uninfected saliva over 0.75-1.1 THz. Other nanoparticles consisting of 100–500 nm antimony, carbon black, zeolite aluminosilicate molecular sieves), Terfenol-D (Tb
0.3
Dy
0.7
Fe
2
), Cu2s,Ag2S, dust collected from bench tops, 10–100 μm size diamond particles, red polystyrene beads, iron particles and graphene sheets were also tested. Sensor sensitivity for uninfected saliva was 0.3 dB/ng and for infected saliva was 0.8 dB/ng. The metamaterial surface studied here enables detection of airborne particles larger than 10 μm in diameter.