Terahertz Sensors Based On Metamaterials And Their Application In Cell Detection

Terahertz technology plays a unique role in astrophysics,communications,nondestructive testing and biomedicine due to its strong penetration,sensitivity to polar molecules,low energy and wide frequency band.As an artificial composite structure with extraordinary physical properties,metamaterial can exhibit local electric field enhancement effect and is very sensitive to the change of external environment.Therefore,metamaterial is very suitable for high sensitive biosensing applications.In this paper,the properties and applications of terahertz(THz)biosensor are introduced firstly,and then domestic and international research progresses of terahertz biosensors which based on metametarials are introduced in detail.Next,the terahertz time-domain spectroscopy(THz-TDS)and measuring method for terahertz band metamaterial information are described.On the basis of this,two structures of EIT-like metamaterial biosensors were designed to detect human tongue squamous cell carcinoma(HSC-3).Ⅰ.Design and simulation of two terahertz band EIT-like biosensors based on metamaterials are presented.One is a concentric ring structure and the other is a metal-wire and double SRR rings structure.Both sensors use flexible material polyimide as substrates,which are sensitive to changes in the refractive index and thickness of the object being measured.Cells with different sizes,concentrations and locations can cause significant changes in the transmission of the sensor.The concentric ring structure senser has more than one transparent window,and also has some advantages for measuring a dispersive medium.Cells located at the gaps of the metal SRR structures can cause the obvious division in transparent window,which makes it possible to detect the very small numbers of cells using this sensor.Ⅱ.The autophagy in human tongue squamous carcinoma cells is detected by using fabricated biosensers.Two groups of human tongue squamous carcinoma cells,untreated and drug-treated to induce autophagy,are selected as subjects for comparative study.The results show that autophagy occurred in the cells under the influence of drugs,which is mainly manifested by changes in cell morphology.It causes changes in the effective permittivity.Drug-treated and untreated cells have different effects on transmission of terahertz sensor,mainly causing a different frequency shift of the EIT-like transparent window.So our sensors can be used to detect whether autophagy has occurred.