Terahertz toroidal metasurface biosensor for sensitive distinction of lung cancer cells

Abstract

Lung cancer is the most frequently life-threatening disease and the prominent cause of cancer-related mortality among human beings worldwide, where poor early diagnosis and expensive detection costs are considered as significant reasons. Here, we try to tackle this issue by proposing a novel label-free and low-cost strategy for rapid detection and distinction of lung cancer cells relying on plasmonic toroidal metasurfaces at terahertz frequencies. Three disjoint regions are displayed in identifiable intensity-frequency diagram, which could directly help doctors determine the type of lung cancer cells for clinical treatment. The metasurface is generated by two mirrored gold split ring resonators with subwavelength sizes. When placing analytes on the metasurface, apparent shifts of both the resonance frequency and the resonance depth can be observed in the terahertz transmission spectra. The theoretical sensitivity of the biosensor over the reflective index reaches as high as 485.3 GHz/RIU. Moreover, the proposed metasurface shows high angular stability for oblique incident angle from 0 to 30°, where the maximum resonance frequency shift is less than 0.66% and the maximum transmittance variation keeps below 1.33%. To experimentally verify the sensing strategy, three types of non-small cell lung cancer cells (Calu-1, A427, and 95D) are cultured with different concentrations and their terahertz transmission spectra are measured with the proposed metasurface biosensor. The two-dimensional fingerprint diagram considering both the frequency and transmittance variations of the toroidal resonance dip is obtained, where the curves for different cells are completely separated with each other. This implies that we can directly distinguish the type of the analyte cells and its concentration by only single spectral measurement. We envisage that the proposed strategy has potential for clinical diagnosis and significantly expands the capabilities of plasmonic metamaterials in biological detection.

Optical Fiber, Nanomaterial, and THz-Metasurface-Mediated Nano-Biosensors: A Review

“…The THz regime is strongly sensitive to the presence of water molecules, which offers the possibility to identify a cancer cell by exploiting the difference in the water content between normal and cancer cells. Chiben Zhang et al [ 203 ] reported the identification of lung cancer cells by using metasurface operating in the THz band. The structure was made from a pair of split-ring resonators (SRRs) placed by facing the gap closed to each other with a 2.5 µm separation, as shown in Figure 9 a. Additionally, on the opposite side of the ring, a small gap is also introduced to the structure.…”

“…The sensitivity was reported as 485.3 GHz/RIU. The effect of height and dielectric dissipation are also investigated, and further details can be found in [ 203 ]. In the experimental part, to measure lung cancer, three different types of lung cancer were considered, i.e., Calu-1, A427, and 95D.…”

Analysis of Evolution of Coupled Lorentz Resonances and Their Sensing Properties in Terahertz Metamaterials

“…Metamaterial-based THz sensor can provide the sensitive detection of the analyte owing to their localized field enhancement properties; exhibiting the variation of the dielectric environment will induce the obvious change of sensing spectra involved with the resonant frequency and linewidth [31,32]. Recent excellent studies show the apparent shifts of both the resonant frequency and depth can be observed in THz toroidal metasurface for sensitive distinction of lung cancer cells [33]. The EIT-like resonance can experience frequency and magnitude variations when the properties of analytes change, showing that the glioma cells can be distinguished directly based on this EIT resonance [34].…”

A Photoexcited Switchable Dual-Function Metamaterial Absorber for Sensing and Wideband Absorption at THz Band

“…A metamaterial is a kind of periodic artificial structure that is composed of sub-wavelength resonant units. Its electromagnetic properties can be artificially controlled by designing its unit cell and it holds important application values in electromagnetic stealth, plate focusing, polarization conversion, and direction modulation [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. The metamaterial absorber is an important research aspect of a metamaterial.…”