| 摘要 |
A novel fluctuation spectroscopy technique based on interferometry is described. The technique, termed scattering interference correlation spectroscopy (SICS), autocorrelates the signal from the forward scattered and the transmitted laser light from nanoparticles (NPs) in solution. SICS has two important features: Firstly, for unlabeled NPs with known refractive index, it analyses not only the diffusion coefficient, but also the effective cross-section and concentration, in a single measurement. Secondly, it can be combined with fluorescence correlation spectroscopy (FCS) for simultaneous analysis of labeled and unlabeled NPs. SICS is here demonstrated on unlabeled M13 phages and on unlabeled NPs of 210 nm down to 26 nm diameter. It is also shown how the combination of SICS and FCS can determine the fraction of fluorescent NPs in a mixture, and estimate Kd from a single binding measurement. |
