The wavelength modulation surface plasmon resonance (SPR) biosensor was designed based on fixing the incident angle of light and measuring the reflected intensities at the resonance wavelength simultaneously. The interaction between β-CD and serum albumin (human serum albumin, bovine serum albumin) was studied with the wavelength modulation SPR sensor, and kinetic constants, thermodynamic constants, and binding percentages were obtained, respectively. In addition, regeneration of the SPR biosensor was also studied. This method provides detailed information on affinities of the β-CD binding to serum albumin. The equilibrium constant of the reaction for the β-CD and HSA was 7.79 μmol/L, while that for the β-CD and BSA was 51.00 μmol/L. The binding percentages were 98.77% and 94.25% for β-CD binding HSA and BSA, respectively. These results indicated that their affinities were very high for β-CD towards HSA and BSA.

Key words: surface plasmon resonance, β-CD, serum albumin, binding percentage