earticle

영어

The combination of Localized Surface Plasmon Resonance (LSPR) with interferometry using gold-capped porous anodic alumina (PAA) layer chip for the detection of C-reactive protein (CRP) antibody-antigen interactions is demonstrated. The combination of LSPR with interferometry on a gold capped PAA layer chip enables two important aspects of optical sensing systems, the shift in λmax and the increment in the absorbance intensity in a new and highly sensitive format. The excitation of the optical characteristics and the detection was performed using only one optical fiber, which made our device user-friendly and suitable for the development of hand-held diagnostic devices. For the fabrication of PAA layer chip, we developed a two-step anodizing method. The porous portion of PAA layer chip consisted of close-packed hexagonal inter-pores, each with a central straight nano-pore perpendicular to the surface of Al surface. Diameters of the nano-pore and the cell were about 60 nm (1.2X1010pores/cm2) and 120 nm, respectively. Then, PAA layer chip surface was deposited with gold by using thermal evaporator. The CRP antibody immobilization was carried out with the functional SAM on the surface of gold-capped PAA layer chip. For the measurement of CRP antibody-antigen interactions, small volumes of label-free CRP antigen were applied onto the surface of gold-capped PAA layer chip. Subsequently, evaluation of optical properties was carried out. In the presence of CRP antigen, the change of absorbance intensity in the interferometric pattern and a significant bathochromic shift was observed.