Preparation of novel composite nanoclusters and their application in the ultrasensitive detection of proteins

An ultrasensitive method for detecting protein by synchronous fluorescence scan technique with a novel composite nanoclusters has been developed. The novel composite nanoclusters has been prepared by an in situ polymerization method and applied as a protein synchronous fluorescence probe. The surface of the composite nanoclusters was covered with functional groups (---COOH, ---CONH---, ---OH). These groups may have "synergistic effect" and play a major role in the ultrasensitive method. The nanoclusters are water-soluble, stable and biocompatible. The synchronous fluorescence intensity of the composite nanoclusters is significantly increased in the presence of trace protein at pH 1.09. Based on this, a new synchronous fluorescence scan (SFS) analysis was developed for the determination of proteins including BSA, HSA and human (gamma)-IgG. The liner range is 0.03–2.0 (mu)g ml^-1 for HSA, 0.02–2.2 (mu)g ml^-1 for BSA and 0.02–1.5 (mu)g ml^-1 for human (gamma)-IgG, respectively. Besides high sensitivity, the method is characterized by good reproducibility, excellent accuracy and few interfering substances.