Nano metamaterials for ultrasensitive Terahertz biosensing.

As a candidate for a rapid detection of biomaterials, terahertz (THz) spectroscopy system can be considered with some advantage in non-destructive, label-free, and non-contact manner. Because protein-ligand binding energy is in the THz range, especially, most important conformational information in molecular interactions can be captured by THz electromagnetic wave. Based on the THz time-domain spectroscopy system, THz nano-metamaterial sensing chips were prepared for great enhancing of detection sensitivity. A metamaterial sensing chip was designed for increasing of absorption cross section of the target sample, related to the transmitted THz near field enhancement via the composition of metamaterial. The measured THz optical properties were then analyzed in terms of refractive index and absorption coefficient, and compared with simulation results. Also, virus quantification regarding various concentrations of the viruses was performed, showing a clear linearity. The proposed sensitive and selective THz detection method can provide abundant information of detected biomaterials to help deep understanding of fundamental optical characteristics of them, suggesting rapid diagnosis way especially useful for such dangerous and time-sensitive target biomaterials.