Surface plasmonic resonance based five layered structure-biosensor for sugar level measurement in human

Abstract

In this paper, five layered Surface Plasmon Resonance (SPR) based optical biosensor has been designed for the detection of sugar concentration level in human body. For accuracy and sensitivity measurement here metamaterial and silica has been considered in the third layer for two different structure, respectively. Considering the advantages of exceptional properties of metamaterials, this is highly sensitive and label-free biosensor that has been simulated and analyzed. And a comparative study has been done by considering angle modulation method for better performance and structural design in SPR based biosensor. An Analysis and Simulation has been done for urine sample with various sugar concentration, present in normal person (0–15 mg/dL), and with diabetic person with 0.625, 1.25, 2.5, 5, and 10 g/dL. From literature surveys it is found that for variation in sugar concentration in urine sample, will have different refractive indices, respectively. Light source of 1632.8 nm is used for excitation of five-layer SPR based biosensor. After simulation it has been observed that by using metamaterial, it provides a much sharper reflectance dip and can significantly improve biosensor’s sensitivity. Comparative study has been made with two above mentioned structural design. As a result metamaterial layer-based structure is found to be highly sensitive in comparison with Silica-based biosensor for small changes in refractive index. It is seen that the small change in refractive index makes it highly sensitive. It is also observed that, for the small variation in refractive index there is a distinct shift in reflectivity in metamaterial based SPR biosensor in compare to the silica-based biosensor. This design will be applicable in measurement of sugar level in diabetic and normal person accurately.