Nano metamaterials for ultrasensitive Terahertz biosensing

Abstract

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.

Terahertz biosensing metamaterial absorber for virus detection based on spoof surface plasmon polaritons

“…Meanwhile, to fulfill the detection for virus, virus samples are assumed as nonmagnetic lossy clads, possessing equivalent complex refractive indices N = α n + i β к , α and β are frequency‐independent parameters in the range of 1.0‐1.4 (for n ) and 1.0‐2.0 (for к ), where α and β determine the virus subtypes and protein concentrations. n and к are the real and imaginary parts of , respectively, where the permittivity ε is modeled by the following formula With ω p = 4.0 THz, ω 0 = 2.8π THz, and γ = 4.0 THz.…”

“…The artificial THz metamaterial and tunable THz‐TDS spectral features enable tremendous promising applications blooming in biomedical engineering territories by taking advantage of metamaterial with strongly confined near‐fields at resonant modes. For instance, it can be applied to medical imaging, time‐sensitive virus biosensing, DNA/RNA analysis and early disease prediction …”

“…More interestingly, the variation in refractive index of the material cladding on the metal surface will change the propagation constant of the SSPPs, the resonance wavelength, the mode field distribution and the phase of guided optical wave . Thus, it provides another significant sensing method in THz regime to effectively detect the micro dielectric changes of virus, polypeptide, and biological antibiotics . On the basis of SSPPs, massive planar metamaterial structures for biosensing based on tightly confined SSPPs mode have been reported, such as nano‐antenna metamaterial, square apertures metasurface, nano‐gap split‐ring metamaterial, and corrugated‐stripe metamaterial …”

“…In this article, Jerusalem cross apertures metamaterial absorber based on the strongly confined SSPPs resonance mode in THz regime is proposed for different subtypes and protein concentration biosensing of AI viruses. Equivalent models for the virus are numerically investigated to extract various compositions of dielectric constants . Besides, simulated detections for different virus subtypes (different N ) are probed with the proposed biosensing metamaterial absorber.…”

“…Besides, simulated detections for different virus subtypes (different N ) are probed with the proposed biosensing metamaterial absorber. According to the protein concentration of three common AI viruses (H5N2, H1N1, H9N2), the compositions of three equivalent models for the AI virus are extracted for the simulations of finite‐difference time‐domain (FDTD) . Shifted resonance frequencies and variational resonant peak values of the proposed metamaterial absorber are observed as a function of virus types and protein concentrations.…”