The rapid detection of cancer cells is crucial for clinical diagnosis in biomedical field. The traditional flow cytometry (FC) in visible band, a fluorescence-labelling detection, gives rise to the complicated sample preparation and the irrecoverable antibody consumption; it blocks the development toward a convenient detection platform with fast, inexpensive and non-labelling. Here, a specifically designed metamaterial based on split ring resonators (SRRs) is proposed. Such metamaterial operating in terahertz (THz) range exhibits polarization-dependent resonances, which are observed both in experiments and simulations. Additionally, the biosensing property of the metamaterial is investigated. On metamaterial surfaces, the lung cancer cells A549 are cultured. Under the irradiation of x-polarized THz waves, it is found that for the cell concentrations from 1×10<sup>5</sup> cells/ml to 5×10<sup>5</sup> cells/ml, the maximum frequency shift Δ<i>f</i> (the frequency difference between measured sample and bare one) at 2.24 THz increases from 15 GHz to 137 GHz, respectively. Such results also imply that a larger cell concentration leads to a higher frequency shift. Subsequently, the samples are further measured at different polarization angles. The results show that for cell concentration of 5×10<sup>5</sup> cells/ml, the Δ<i>f</i> exhibits the same value of 130 GHz when polarization angle equals 30° and 150°, and 15 GHz when polarization angle equals 60° and 120°. Our proposed metamaterial may supply a potential biosensing method for the detection of cancer cells, exhibiting a new insight toward the cancer cell biosensing with certain information of polarization response.
Real-time detection for living cells in vitro is essential for cell physiology, leading to a strong requirement of low cost and label free biosensors. At present, the terahertz plasmonic metamaterials (TPMMs) are an especially attractive application for biosensing owing to their sharp resonances respond. Compared with traditional biosensors, such as flow cytomertry, the TPMMs biosensors have many unique advantages, containing real-time monitoring, free label and high sensitivity. In this paper, we proposed a TPMMs which is designed by digging out periodically arranged regular hexagonal holes on the metal plate with the thickness of 200 nm. The samples of the TPMMs is used as a platform for detecting liver cancer cell GEP2 concentration at five levels (1 × 10<sup>4</sup>, 5 × 10<sup>4</sup>, 1 × 10<sup>5</sup>, 3 × 10<sup>5</sup> and 5 × 10<sup>5</sup>cells/ml). The results show that The THz PMMs biosensor cannot distinguish cell concentrations within the orders of magnitude between 1 × 10<sup>4</sup> and 5 × 10<sup>4</sup> cells/ml, however, it can distinguish cell concentrations within the orders of magnitude between 1 × 10<sup>4</sup> and 1 × 10<sup>5</sup> cells/ml based on the x-polarized reflection spectrum TPMMs biosensor. On the other hand, the transmission spectrum TPMMs biosensor has a significant detectability of the orders of magnitude cell concentration between 10<sup>4</sup> and 10<sup>5 </sup>cells/ml. The proposed TPMMs biosensor paves a fascinating platform for have been widely applied for cell detection, biotechnology.