Characterization of surface plasmon resonance wavelength by changes of protein concentration on protein chips

We have characterized surface plasmon resonance (SPR) wavelength as a function of protein concentration on protein array by a new ex situ SPR sensor based on wavelength interrogation. The spectral range of the spectrometer was from 500 to 700 nm and the surface structure of protein array is consisted of glass/Ti/Au/tTGase/air (ex situ). The ex situ SPR sensor was self-constructed and its detection limit of minimal refractive index variation was calculated to be 7.6×10−5. The experimental result showed that the SPR wavelength was linearly shifted with respect to the increment of tissue transglutaminase concentration from 20 to 120 μg/ml. These results suggest that the ex situ wavelength interrogation-based SPR sensor can be used as a good tool for the analysis of protein array.