Signal Amplification of Surface Plasmon Resonance based on Gold Nanoparticle- Antibody Conjugate and its Application to Protein Array

Surface plasmon resonance (SPR) is a versatile, convenient, and low-power technique that may be used to determine the change of thin dielectric film. Although the sensitivity is very high, when small molecule is a target for immobilization or detection, the changes in the angledependent attenuated total reflectance (ATR) are often small so the use of SPR method is limited for generic application. The specific interaction between target molecules and Au nanoparticle-antibody conjugate induce the change of the surface properties such as mass and electric coupling, which can be represented as the change of plasmon resonance angle. In this study, gold (Au) nanoparticle-antibody conjugate was applied for the signal enhancement of SPR. Antibody was immobilized with an oriented configuration on Au surface. Au nanoparticleantibody conjugated was prepared after coagulation test based on spectrophotometric method. Experimental results showed that tremendous signal amplification was observed, which represent remarkable advances of SPR technique for ultrasensitive detection. And the detection limit of binding events was also improved.