Magneto-plamonic nanoparticles enhanced surface plasmon resonance TB sensor based on recombinant gold binding antibody

Abstract

The magneto-plamonic nanoparticles (MPNs) have been employed to enhance the signal of surface plasmon resonance (SPR) spectroscopy to gain new insight into MPN and gold film SPR interaction. Three different morphologies MPNs (sphere, short spiky and long spiky) of Fe3O4@Au nanoparticles with good dispersion were synthesized and characterized carefully. A sandwich SPR immunosensor was constructed by immobilizing gold binding anti-CFP-10 (Ab1) onto a gold chip surface via Au-S bond firstly. Gold binding anti-CFP-10 (Ab2) captured on MPN surface was utilized to amplify the SPR signals specifically. Compared with spiky MPNs, the structure of spherical MPN, which concentrates the electric charge density and immobilize more Abs on its surface coverage, could enhance the electronic coupling effect significantly. Attribute to the super paramagnetism of MPNs, a facile solution route was fabricated to capture and separate analyte from the real sample by outside extend magnetic field. Implementation of MPNs results in 30-fold enlargement of the SPR signal at the limit of detection. To this end, an immunoassay is carried out that couples the specificity of antibody-antigen interactions with the high sensitivity based on spherical MPNs signal enhancement SPR.