Direct synthesis of water soluble CuS and CdS nanocrystals with hydrophilic glucuronic and thioglycolic acids

Synthetic methods for high-quality monodispersed nanoparticles in organic solvents are well-developed, but their biological applications are restricted due to the lack of water solubility and tailored surface chemistry. Herein we report on the synthesis of water soluble nanocrystals of CuS and CdS via the direct use of hydrophilic glucuronic and thioglycolic acid ligands. The employed method successfully derived water-soluble particles. The solubility test revealed that the glucuronic acid was a more effective ligand for rendering the nanocrystals water soluble. However the morphologies of the glucuronic acid-capped nanocrystals showed a higher degree of agglomeration thought to be as a result of the interaction between the OH groups. The thioglycolic acid ligand was less effective than the glucuronic acid and this was attributed to the non-aromatic nature of the ligand and the presence of fewer polar groups. Nevertheless, both the CuS and CdS thioglycolic acid-capped nanocrystal showed better dispersity.