Quantitative characterization of quantum dot-labeled lambda phage for Escherichia coli detection

Biotechnol Bioeng. 2009 Dec 15;104(6):1059-67. doi: 10.1002/bit.22488.


We characterize CdSe/ZnS quantum dot (QD) binding to genetically modified bacteriophage as a model for bacterial detection. Interactions among QDs, lambda (lambda) phage, and Escherichia coli are examined by several cross-validated methods. Flow and image-based cytometry clarify fluorescent labeling of bacteria, with image-based cytometry additionally reporting the number of decorated phage bound to cells. Transmission electron microscopy, image-based cytometry, and electrospray differential mobility analysis allow quantization of QDs attached to each phage (4-17 QDs) and show that lambda phage used in this study exhibits enhanced QD binding to the capsid by nearly a factor of four compared to bacteriophage T7. Additionally, the characterization methodology presented can be applied to the quantitative characterization of other fluorescent nanocrystal-biological conjugates.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Bacteriophage lambda / metabolism*
  • Bacteriophage lambda / physiology*
  • Base Sequence
  • Capsid Proteins / metabolism
  • Escherichia coli / isolation & purification*
  • Escherichia coli / virology
  • Flow Cytometry
  • Fluorescence
  • Microscopy, Electron, Transmission
  • Molecular Sequence Data
  • Quantum Dots*
  • Staining and Labeling / methods*
  • Virus Attachment*


  • Capsid Proteins