One-step synthesis of biofunctional carbon quantum dots for bacterial labeling

Cheng I. Weng, Huan Tsung Chang, Chia Hua Lin, Yu Wei Shen, Binesh Unnikrishnan, Yu Jia Li, Chih Ching Huang*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

144 Scopus citations

Abstract

In this study, we used a simple one-step dry heating method to synthesize mannose-modified fluorescent carbon quantum dots (Man-CQDs) from solid ammonium citrate and mannose, and successfully applied for labeling Escherichia coli. The highly soluble Man-CQDs had an average particle diameter of 3.1±1.2nm and exhibited a quantum yield of 9.8% at excitation and emission wavelengths of 365 and 450nm, respectively. The fluorescent Man-CQDs could selectively bind to the FimH lectin unit in the flagella of the wild-type 1 E. coli K12 strain. We optimized the labeling efficiency of the Man-CQDs by controlling the ratio of ammonium citrate to mannose during their synthesis. The specific binding of the mannose units to E. coli allowed quantitative detection of the bacteria at levels down to 450 colony forming units mL-1 in lab samples, and facilitate the application of the Man-CQDs for bacterial analyses of real samples (tap water, apple juice, human urine). The synthesis of our Man-CQDs, their labeling, and their use in the detection of bacteria were all simple, inexpensive and efficient processes.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalBiosensors and Bioelectronics
Volume68
DOIs
StatePublished - 05 06 2015
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2014 Elsevier B.V.

Keywords

  • Bacterial labeling
  • Carbon quantum dots
  • E. coli
  • Lectin
  • Mannose

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