Abstract: Two types of CdS nanoparticles with different fluorescence characteri stics were directly synthesized in an aqueous solution by using mercaptoacetic a cid as the stabilizer. The fluorescence spectra show that these two types of CdS nanoclusters emit strong blue and yellow fluorescence respectively. T he biomolecules such as the functional protein, specific antibodies can be coupled with the free carboxyl groups on CdS nanoparticle by means of t heir amino-groups, which has laid the foundation of simultaneously labelling se veral kinds of biololgical macromolecules.

Key words: CdS, nanocluster, fluorescence spectroscopy