The detection application of CdS quantum dots in labeling DNA molecules.

CdS nanoparticles with narrow symmetric emission and stable photochemical properties are synthesized. The particles are labeled on the probe DNA molecules due to the electrostatic interaction between the amidocyanogen DNA molecules with positive charges and the free carboxyl on the surface of CdS nanocrystals with negative charges. We find that the fluorescence intensity of the CdS-DNA decreases with the increasing temperature. The target DNA molecules immobilized on the quartz slides in two patterns, random and linear array, are successfully detected by the CdS labeled probe DNA molecules using the fluorescence of the particles. This may offer a more stable and quantitative mode of fluorescence in-situ research and biologic analysis.