Authors: H-S. Kim, J-H. Kim, S-H. Ko, Y-J. Cho, J-H Kim
Affilation: Ajou University, Korea
Pages: 483 - 486
Keywords: SPR, Au nanoparticle, sensor, label-free
In order to overcome the sensitivity limitation of SPR, nanoparticle-coupled SPR biosensors have explored since nanoparticles may significantly enhance the sensitivity by 1-2 orders of magnitude. Although the nanoparticle conjugated method contributes to the enhancement of the sensitivity, it does not take an advantage of SPR from the viewpoint of label-free detection. Herein we demonstrate the sensitivity enhancement with Au nanoparticles coupled- SPR immuno-sensor chip on which the specific size and surface density of the particles controlled as a label-free detection system. Au nanopariticles were synthesized and selected with a specific size. Surface density of immobilized 30 nm Au nanoparticles on bare Au film was estimated as 1x109 ea/cm2 using atomic force microscopy. With systematic control of the size of the Au nanoparticle and thickness of the bare Au film, it was found that 30 nm Au particles on 50 nm thick Au film demonstrated the largest resonance angle shift for surface reaction on the chip. This enhancement may result from both the effective surface area increase and the amplification of the resonance resonance effect. For human immunoglobulin G antibody-antigen analysis, this Au nanoparticle immobilized Au substrate shows highest SPR sensitivity comparing to the conventional bare Au film chip.