Graphene-MoS2-Au-TiO2-SiO2 Hybrid SPR Biosensor: A New Window for Formalin Detection

Abstract

In this article, numerically a surface plasmon resonance (SPR) biosensor is developed based on Graphene-M­­­­_OS₂-Au-TiO₂-SiO₂ hybrid structure for formalin detection. This developed sensor sensed the presence of formalin by applying attenuated total reflection (ATR). In ATR method, we developed and observed two characteristics curve, one is “SPR angle versus minimum reflectance (R_min)” and another is “SPR frequency (SPRF) versus maximum transmittance (T_max). In the proposed sensor, Chitosan is used as probe legend to perform specific reaction with the formalin (40% formaldehyde) as target legend. Here, graphene and MoS₂ both are used as biomolecular acknowledgment element (BAE). And TiO₂ as well as SiO₂ bilayers are used to improve sensor sensitivity and Gold (Au) is to sharp SPR curve. In numerical results, the variation of SPRF and SPR angle for inappropriate sensing of formalin is quiet insignificant which confirms the absence of formalin. On the other hand, these variations for appropriate sensing is considerably significant that confirms the presence of formalin. At the end of this article, a study of variation of sensitivity of the proposed biosensor in corresponding to the increment of refractive index with a refractive index step 0.01 RIU is measured. In inclusion of TiO₂-SiO₂ bilayers with Graphene-M­­­­_OS₂, maximum sensitivity of 85.375% more is numerically reported.