Sensitivity Enhancement of a Miniaturized Surface Plasmon Resonance Sensor Using Combination of Self-Assembled Mono layer and Protein G

Abstract

The detection capabilities of surface plasmon resonance (SPR) sensor chips modified with protein G, a self-assembled monolayer (SAM), and a combination of protein G and a SAM were investigated and compared using a miniaturized SPR sensor system. The miniaturized SPR system had two flow channels, with one used as a reference. To immobilize the antibodies on the SPR sensor chip for the detection of C-reactive protein (CRP), different linker molecules were formed on the gold SPR sensor chip at the beginning of the experiment. The CRP has been reported as a biomarker of future cardiovascular events. The antibody of CRP and bovine serum albumin (BSA) were then sequentially injected. The responses to CRP at concentrations of 0.5, 1, 3, and 5 μg/ml were observed and the sensitivities of each system compared. The SPR sensor chips modified with the protein G on the SAM layer exhibited the highest sensitivity and a stable linearity. The results demonstrated the feasibility of using the proposed SPR immunosensors for detecting CRP for early diagnosis without any additional chemical treatments. Copyright © 2012 American Scientific Publishers.