CdSe/ZnS quantum dots with multi-shell protection: Synthesis and application in the detection of ractopamine residue in swine urine

Changhua Zhou, Hang Yuan, Xin Wang, Huaibin Shen, Yi Guo, Li Xu, Feng Wu, Ma Lan, Lin Song Li

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

In this paper, we aimed to prepare ultra-stable aqueous CdSe/ZnS quantum dots (QDs) as fluorescent labels to detect ractopamine (Rac) residue in swine urine based on a competitive lateral flow immunoassay (LFIA) biosensor system. Such CdSe/ZnS QDs with multi-shell protection were prepared by various shellencapsulating strategies, which included preparing aqueous amphiphilic oligomer-CdSe/ZnS QDs, encapsulating aqueous CdSe/ZnS QDs within a silica shell, grafting the silica surface with long-chain hydrocarbons, and re-transferring the hydrophobic QDs-SiO2 nanoparticles into water with amphiphilic oligomer. The size of multishell protected CdSe/ZnS QDs tested by TEM could be tuned from 11.7 to 27.3 nm. The QDs can be stabilized in a broad range of chemical conditions, including strong acidic solutions (pH = 1) and high concentrations of salts, and can withstand thermal treatment at 80 °C. Even in swine urine, the multi-shell protected CdSe/ZnS QDs can still retain their high fluorescence. Eventually, the reliable detection limit for Rac residue by using CdSe/ZnS QDs with multi-shell protection in swine urine is successfully pushed down to 0.1 ng/mL, which is over 30 times higher than commercial Rac LFIA strips.

Original languageEnglish (US)
Pages (from-to)285-294
Number of pages10
JournalScience of Advanced Materials
Volume5
Issue number3
DOIs
StatePublished - Jul 23 2013

Keywords

  • CdSe/ZnS QDs
  • Multi-Shells protecting
  • Ractopamine residue
  • Silica

ASJC Scopus subject areas

  • Materials Science(all)

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