Controlled synthesis of CdSe and CdSe/CdS core/shell nanoparticles using Gemini surfactant Py-16-10-16 and their bioconjugates with BSA

CdSe and CdSe/CdS core/shell nanoparticles (NPs) were synthesized by using Gemini surfactant, 1,10-bis(alpha-hexadecyl pyridine) decamethylene dibromide (abbreviated Py-16-10-16), as a soft template. Subsequent analysis revealed that the as-synthesized CdSe NPs and CdSe/CdS core/shell NPs were highly luminescent with quantum yields of 18% and 35%, respectively, compared with Rhodamine 6G (95%). Furthermore, when the nanoparticles were conjugated with bovine serum albumin (BSA) in PBS buffer solution (pH 7.40), the fluorescence intensity of the BSA system was quenched by the addition of CdSe/TGA or CdSe/CdS/TGA NPs, while the fluorescence intensities of CdSe/TGA and CdSe/CdS/TGA NPs were enhanced by the addition of BSA. This enhancement and quenching of the fluorescence intensity by conjugating with BSA could be used to determine the albumin concentration. (C) 2009 Elsevier Inc. All rights reserved.