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Determination of Albumin Using CdS/SiO 2 Core/shell Nanoparticles as Fluorescence Probes
Author(s) -
Zhu Changqing,
Liu Meigui,
Wang Peng,
Cao Ming,
Cao Chun
Publication year - 2009
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200990306
Subject(s) - chemistry , bovine serum albumin , fluorescence , detection limit , nanoparticle , biocompatibility , passivation , calibration curve , analytical chemistry (journal) , microemulsion , nuclear chemistry , shell (structure) , aqueous solution , chromatography , chemical engineering , organic chemistry , materials science , pulmonary surfactant , biochemistry , composite material , physics , quantum mechanics , layer (electronics) , engineering
CdS quantum dots (QD) were capped with SiO 2 via a microemulsion method for reducing the toxicity and imparting the biocompatibility of the CdS QD. The resulting CdS/SiO 2 core/shell nanoparticles (NP) showed an improved water‐solubility and stability even in pH 4.0 acidic medium. Their fluorescence could be effectively enhanced in the presence of bovine serum albumin (BSA), due to the passivation effect of BSA on the surface of the NP. Furthermore, the concentration dependence of the fluorescence intensity obeys the Langmuir‐type binding isotherm. Thus a novel fluorescence enhancement method for the determination of BSA has been developed using the less‐toxic CdS/SiO 2 core/shell NP as probes. Under optimal conditions, the linear range of calibration curve is 0.6–30 µg·mL −1 , and the detection limit is 0.18 µg·mL −1 . Compared with the water‐soluble CdS NP without SiO 2 shell, the CdS/SiO 2 core/shell NP exhibited slightly lower fluorescence response to BSA as well as other coexisting substances, such as heavy and transition metals, due to the inhibition of SiO 2 shell. The proposed method was applied to the quantification of BSA in synthetic and serum samples with satisfactory results.