Abstract
In this paper, a core-shell based on the Fe(3)O(4)@SiO(2)@Au nanoparticle amplification technique for a surface plasmon resonance (SPR) sensor is proposed. Fe(3)O(4)@SiO(2)@AuNPs were used not only to amplify SPR signals, but also to rapidly separate and enrich T-2 toxin via an external magnetic field. We detected T-2 toxin using the direct competition method in order to evaluate the amplification effect of Fe(3)O(4)@SiO(2)@AuNPs. A T-2 toxin-protein conjugate (T2-OVA) immobilized on the surface of 3-mercaptopropionic acid-modified sensing film competed with T-2 toxin to combine with the T-2 toxin antibody-Fe(3)O(4)@SiO(2)@AuNPs conjugates (mAb-Fe(3)O(4)@SiO(2)@AuNPs) as signal amplification elements. With the decrease in T-2 toxin concentration, the SPR signal gradually increased. In other words, the SPR response was inversely proportional to T-2 toxin. The results showed that there was a good linear relationship in the range of 1 ng/mL~100 ng/mL, and the limit of detection was 0.57 ng/mL. This work also provides a new possibility to improve the sensitivity of SPR biosensors in the detection of small molecules and in disease diagnosis.