Biosensors Based On Surface Plasmon Polaritons Applied In PoCT(Point-of-Care-Testing)

The progress of science and technology promotes the development of society,facing the deteriorating living environment,the diversity of diseases caused by food pollution,industrial haze and deterioration of water quality has attracted wide attention,tracking the health status of human body timely and anywhere has become an urgent biomedical issue to be tackled.Therefore,real-time health monitoring and convenient medical security in modern medicine are facing enormous challenges,but also put forward higher requirements for biomedical health care system.Point-of-Care-Testing(PoCT)has gradually become an urgent need for the general public.PoCT is a kind of detection method which is carried out on the sampling site or in real time and can quickly get the test results by using portable analytical instruments and matching reagents.The surface plasmon biosensor Applied to PoCT(Point-of-Care-Test)has been developed according to the research work.The main work of this paper is carried out in two directions: the first kind of surface plasmon sensor chip,which combines the advanced THz technology and metamaterial theory,is applied to the biosensor detection of biological macromolecules;the second type is the design of surface plasmon biosensor in microwave and millimeter wave bands,which is commonly used in the detection of micro-dielectric constant,skin cancer and skin cancer,biosensing of water content in biological tissues.Specific research contents and achievements are as follows:As a promising candidate for rapid and ultrasensitive sensing of biomolecules,terahertz time-domain spectroscopy(THz-TDS)can be considered with superior performance in label-free,non-contact,non-invasive and non-destructive detection.In particular,almost significant conformational information can be captured with THz-TDS.Meanwhile,THz metamaterial or metasurface biosensing chips based on THz-TDS were proposed to promote the detection sensitivity within strong local field-matter enhancement.In this paper,the ultrasensitive terahertz(THz)biosensing metamaterial and metasurface for DNA/RNA detecting based on spoof surface plasmon polaritons(SSPPs)are probed.The simulated results show the maximum frequency sensitivity of the proposed metamaterial and metasurface for DNA/RNA biosensing can respectively approach to 2.52 THz/refractive index unit(RIU)and 2.23THz/RIU.In addition,the film thickness sensitivities of metamaterial and metasurface biosensors are respectively higher than 71.1 GHz/?m and 79.2 GHz/?m when the thickness of biomaterial is thinner than 4 ?m.All these ascendant performances achieved in the proposed metamaterial and metasurface biosensors can be realized and exploited for ultrasensitive biomolecules detection,health monitoring,medical film sensing and safety inspection in THz regime.A planar Jerusalem cross metamaterial absorber biosensor for different virus detection based on spoof surface plasmon polaritons(SSPPs)in THz band is investigated.Strongly confined SSPPs modes are extracted from the absorption spectra of biosensing metamaterial absorber associated with local field enhancement.Meanwhile,equivalent complex refractive index(N)of different virus subtypes and protein concentrations is numerically investigated for virus detection.Besides,simulated detections for different virus subtypes(different N)are probed with the proposed biosensing metamaterial absorber.Especially for the simulated detections of three representative Avian Influenza(AI)viruses(H5N2,H1N1,H9N2),the proposed THz biosensing metamaterial absorber chip performed ultrasensitive sensitivity and high resolution by extracting the shifted resonance frequencies(?F)and the changed values at maximum absorptions(?A).All these foundings show great significance on a rapid real-time procedure for diseases diagnosis especially for the contagious and time-sensitive target virus.Besides,this paper demonstrates three microwave biosensors in microwave and millimeter wave regime based on the spoof surface plasmon polaritions(SSPPs)excited by a planar plasmonic waveguide,which can be used in cancer diagnosis and in-vivo measure the water content timely and accurately.(a)A symmetric Mirror-metamaterial element-based microstrip-line biosensor based on spoof surface plasmon polaritons is proposed to detect micro change in dielectric.(b)A SSPPs microstrip-line reference-line biosensor is simulated and fabricated in sensing cutaneum carcinoma in skin tissues.And the equivalent complex dielectric constant of different water contents of human skin tissues is numerically computed.The biosensing results show high resolution in distinguishing the situation of cancerization.(c)A SSPPs staggered grid biosensor is fabricated and measured using the vector network analyzer with a human finger as a real model.Experimental results of the biosensor with/without normal human finger skin tissues and pure water have a good agreement with our simulation.In conclusion,the three SSPPs biosensors have potential applications for the areas of in-vivo measurement of the human stratum corneum,water content with topical cosmetics,early diagnostics of superficial tumors such as malignant melanoma and lymphatic cancer,and also in the guiding tumors resection.