Using oligonucleotide-functionalized Au nanoparticles to rapidly detect foodborne pathogens on a piezoelectric biosensor

J Microbiol Methods. 2008 Apr;73(1):7-17. doi: 10.1016/j.mimet.2008.01.004. Epub 2008 Jan 18.


A circulating-flow piezoelectric biosensor, based on an Au nanoparticle amplification and verification method, was used for real-time detection of a foodborne pathogen, Escherichia coli O157:H7. A synthesized thiolated probe (Probe 1; 30-mer) specific to E. coli O157:H7 eaeA gene was immobilized onto the piezoelectric biosensor surface. Hybridization was induced by exposing the immobilized probe to the E. coli O157:H7 eaeA gene fragment (104-bp) amplified by PCR, resulting in a mass change and a consequent frequency shift of the piezoelectric biosensor. A second thiolated probe (Probe 2), complementary to the target sequence, was conjugated to the Au nanoparticles and used as a "mass enhancer" and "sequence verifier" to amplify the frequency change of the piezoelectric biosensor. The PCR products amplified from concentrations of 1.2 x 10(2) CFU/ml of E. coli O157:H7 were detectable by the piezoelectric biosensor. A linear correlation was found when the E. coli O157:H7 detected from 10(2) to 10(6) CFU/ml. The piezoelectric biosensor was able to detect targets from real food samples.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Bacterial / genetics
  • Animals
  • Biosensing Techniques / methods*
  • Cattle
  • DNA, Bacterial / genetics
  • DNA, Bacterial / isolation & purification
  • Electrochemistry
  • Escherichia coli O157 / genetics
  • Escherichia coli O157 / isolation & purification*
  • Escherichia coli Proteins / genetics
  • Food Microbiology*
  • Gold / analysis
  • Metal Nanoparticles / analysis*
  • Nucleic Acid Hybridization / methods*
  • Oligonucleotides / chemical synthesis
  • Oligonucleotides / genetics*
  • Polymerase Chain Reaction
  • Sensitivity and Specificity


  • Adhesins, Bacterial
  • DNA, Bacterial
  • Escherichia coli Proteins
  • Oligonucleotides
  • eaeA protein, E coli
  • Gold