5,5'-Dithiobis( succinimidyl-2-nitrobenzoate) Functionalized Surface-enhanced Raman Scattering Nanoprobe for Immunoassay

A biofunctionalized nanoprobe for surface-enhanced Raman scattering( SERS)-based immunoassay was designed. 5,5'-Dithiobis( succinimidyl-2-nitrobenzoate)( DSNB) was employed as a linker for protein and gold nanoparticle,which can help to maintain the biological activity of the proteins. Besides that,DSNB possesses a high Raman scattering section,which can be used as the SERS probe as quantitative determination of proteins. Two kinds of biological systems( avidin-streptavidin and antigen-antibody) were selected for the target protein and nanoprobe specific binding to the protein chip. Meanwhile,silicon slide was employed as a carrier,which provides a Raman peak at 520 cm-1and can be used as a good internal standard for quantitative analysis of proteins. Using this method,anti-human Ig G concentration in solutions can be quantitatively measured at concentrations as low as 5 pg / m L.