An Immune AuRu Nanoalloy Probe for Trace CA125 Using Resonance Rayleigh Scattering as Detection Technique
The AuRu nanoalloy (GR) which Au/Ru molar ratio of 32:1 was prepared by the sodium borohydride reduction method. In the condition of pH 6.0, the GR was used to label CA125 antibody (Ab) to obtain an immunonanoprobe for CA125 (GRAb). In pH 7.0 citric acid-Na2HPO4 buffer solution, GRAb was aggregated nonspecifically to big clusters, which showed a strong resonance Rayleigh scattering (RRS) peak at 278nm. When CA125 was added, GRAb reacted specifically with CA125 and GR dispersive in the solution, which led to the RRS intensity decreased greatly. The decreased RRS intensity was linear to the concentration of CA125 in the range of 1.3-80 U/mL, a detection limit of 0.81 U/mL. The proposed method was applied to detect CA125, with satisfactory results.