Purification of denatured bovine serum albumin coated CdTe quantum dots for sensitive detection of silver(I) ions

Abstract

CdTe quantum dots (QDs) were synthesized in aqueous solution with 3-mercaptopropionic acid as the stabilizer. Chemically reduced bovine serum albumin (BSA) was used to modify the surface of the QDs. Experimental results showed that the denatured BSA (dBSA) could be effectively conjugated to the surface of CdTe QDs. Column chromatography was used to purify the conjugates and determine the optimal ratio of dBSA to QDs. Further experimental results showed that the conjugation of QDs by dBSA efficiently improved the photoluminescence quantum yield, the chemical stability of QDs and their stability against photobleaching. A facile and sensitive method for determination of silver(I) ions was proposed based on the fluorescence quenching of the dBSA-QDs. Under the optimal conditions, the relative fluorescence intensity decreased linearly with the concentration of the silver(I) ions in the range 0.08-10.66 microM. The detection limit was 0.01 microM. This study provides a new method for the detection of metal cations.

Fluorescent nanoparticles for chemical and biological sensing

“…In principle, competitive binding of the ligands between the analytes and the QDs would alter the luminescence of NPs, suggesting a feasible route to developing sensing constructs. Recently, a lot of metal ions sensors for Pb 2+ [75], Cu 2+ [76,77], Hg 2+ [78], Ag + [79], Cr 3+ [80], etc., have been developed based on the thios-ligand competition-induced fluorescence quenching.…”

Luminescence of Polyethylene Glycol Coated CdSeTe/ZnS and InP/ZnS Nanoparticles in the Presence of Copper Cations

“…[27] The PL of ZnS:Mn QDs protected with a thick silica shell is efficiently quenched by Cu 2 + but not Pb 2 + , and this is attributed to different diffusion properties of the cations in silica. [19] Organic coatings such as chitosan, [20] polyamidoamine dendrimer, [29] or bovine serum albumin [21,43] have been described to play a role in access of the cations to the QD surface and therefore the PL quenching efficiency. However, this role is not clear.…”

Selective detection of parathion-methyl based on near-infrared CuInS2 quantum dots

“…Many metal ions, such as Cu 2+ , Hg 2+ , Pb 2+ , Co 2+ and Ag + , could quench the PL intensity of QDs (Cai, Shi, Zhao, & Ma, 2012;Liu, Pang, Na, & Su, 2014;Wang et al, 2007;Yang, Ma, Yu, & Su, 2011). It can be seen from Fig.…”