Detection of β-Lactoglobulin by a Porous Silicon Microcavity Biosensor Based on the Angle Spectrum

In this paper, carbon quantum dot-labelled beta-lactoglobulin antibodies were used for refractive index magnification, and beta-lactoglobulin was detected by angle spectroscopy. In this method, the detection light is provided by a He-Ne laser whose central wavelength is the same as that of the porous silicon microcavity device, and the light source was changed to a parallel beam to illuminate the porous silicon microcavity' surface by collimating beam expansion, and the reflected light was received on the porous silicon microcavity' surface by a detector. The angle corresponding to the smallest luminous intensity before and after the onset of immune response was measured by a detector for different concentrations of beta-lactoglobulin antigen and carbon quantum dot-labelled beta-lactoglobulin antibodies, and the relationship between the variation in angle before and after the immune response was obtained for different concentrations of the beta-lactoglobulin antigen. The results of the experiment present that the angle variations changed linearly with increasing beta-lactoglobulin antigen concentration before and after the immune response. The limit of detection of beta-lactoglobulin by this method was 0.73 mu g/L, indicating that the method can be used to detect beta-lactoglobulin quickly and conveniently at low cost.