Submitted to: Trade Journal Publication
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/5/2009
Publication Date: 8/5/2009
Citation: Fu, J., Park, B., Zhao, Y. 2009. Nanorod mediated surface plasmon resonance sensor based on effective medium theory. Applied Optics 48: 4637-4649. Interpretive Summary: Food pathogens have become a serious danger to human lives and sometimes low concentrate level of bio-threat agents can be harmful. Therefore, accurate method with high sensitivity and specificity is needed for pathogenic bacteria detection. This paper reports food related nanotechnology for food pathogen detection using a surface plasmon resonance (SPR). In this study, a nanorod mediated SPR sensor was investigated and a new SPR sensor was designed based on effective medium theory. Increasing high aspect ratio by nanorod surface provided more analyte absorption property to understand anisotropic nanorod layer in a SPR sensor. This innovative nanotechnology-based detection method can be used for food safety and security applications.
Technical Abstract: A novel nanorod mediated surface plasmon resonance (SPR) sensor was investigated for enhancing sensitivity of the sensor. The theoretical model containing an anisotropic layer of nanorod was investigated using four-layer Fresnel equations and effective medium theory. The properties of the nanorod mediated SPR curves, such as the reflectance minimum, SPR resonance angle, and SPR curve width in the environment with refractive index 1 and 1.33, versus the metal thin film thickness, length and diameter of nanorod were studied. An optimal configuration was proposed based on the theoretical analysis. Compared to the conventional thin metal film SPR configuration, the nanorod mediated SPR sensor presents a larger resonance angle shift and the sensitivity enhancement increases with increasing refractive index of the target analyte. Therefore, the sensor can be designed based on estimated refractive index changes induced by targeted interactions for enhancing the sensitivity.