The Detection Research Of A Reduced Cytochrome C Based On Surface Plasmon Polaritons Resonance

Surface Plasmon Polaritons (SPPs) is coherent oscillations of conduction electrons on a metal surface excited by electromagnetic radiation at a metal-dielectric interface, and it is the result of combination of light and nanometal perfectly SPPs is sensitive to the refractive index changes around metallic structures, it has attracted tremendous attentions utilizing its potentials in optical sensing. SPPs technology shows its unique characteristics for biomolecular interaction,biology molecular detection and imaging, and so on, because of its specific advantages. Based on the plasmon resonance energy transfer (PRET), we investigate the transmission characteristics of a one-dimensional metallic grating and a metallic slit covered by a reduced cytochrome (Cytc) molecule layer by using the finite-difference time-domain (FDTD) method. This research work can offer theoretical reference for the design of biological detector devices, and it has been shown to have great potential in ultrasensitive biological sensing and in vivo molecular imaging. The details are as follows:(1) Light transmission characteristics through one dimensional metallic grating covered by a reduced cytochrome c molecule layer is investigated using finite difference time domain method. It is found that the introduction of reduced Cyt c molecule layer leads to a transmission dip due to PRET from metallic grating to Cyt c molecules, and it implies that there exist two resonance mixed mode in the system corresponding to surface plasmon polaritons mode and localized surface plasmon mode which have obvious resonance spectral response to the Cyt c adsorbed on the structure. The findings expand our understanding of the PRET phenomenon and have potential applications in molecule identification and detection. Meanwhile, the effects of structure parameters were analyzed in our article. The transmission dip depth can be controlled by the period of metallic grating, the width and length of slit, and the Cyt c molecules layer number, while the transmission dip wavelength is unchanged with these parameters. This suggests that the transmission dip wavelength is decided by the nature of the Cyt c molecules. The transmission spectrum varies with the different structural parameters, which show that the structure parameters optimization is also the key to the device design success in practice.(2) Light transmission characteristics through a metallic slit covered by a reduced Cyt c molecule layer is investigated using finite difference time domain method. Comparison with one dimensional metallic grating, its transmission spectrum appears the same physical phenomenon and there is a transmission dip in the transmission spectrum. It suggests that the localized surface plasmon energy of the slit transfers to Cyt c molecules. The transmission of metallic the slit with different structure parameters are also studied in our articles. Our research shows that the transmission rate is low, but relatively transmission effect is obvious Based on PRET,LSP technology has the potential applications in molecule identification and detection.