You are here

Research Spotlight: Validation of Gold Nanoparticle DNA-based Biosensors for the Detection of Non-PCR Amplified Bacterial Foodborne Pathogens in Food Matrices

Wednesday, February 25, 2015

This project introduces protocol efficiencies and completes validation of a simple, economical, and portable DNA-based biosensor. This biosensor detection system will perform sensitive, rapid, PCR-independent detection of foodborne pathogens within food matrices both in lab and field settings.


There are multiple commercially available detection methods for bacterial food pathogens using microbiological, immunological, and molecular biological techniques.  Although, these detection mechanisms are accurate they can take between 2-7 days for confirmation and require special reagents, large equipment, and facilities.

Equally, several biosensors for rapid detection of biological pathogens incorporating nanoparticles have been developed, however, most of these systems require purified and PCR amplified DNA targets.  Comparable to the commercially available options, these PCR-based systems are complex, expensive, time-consuming, and labor-intensive.

Validation of Gold Nanoparticle DNA-based Biosensors


The DNA-based biosensor system can detect specific genomic DNA targets extracted from bacterial samples or contaminated food matrices using magnetic nanoparticles to isolate and pull out the pathogenic DNA targets and gold nanoparticles for signal amplification.  This technology eliminates the need for PCR amplification while still retaining the PCR sensitivity.

At the present time the total time needed to go from sample preparation to detection is approximately six to seven hours. Current efforts involve optimizing the limits of the incubation and extraction steps involved in the DNA isolation from test samples down to one and a half hours, and optimizing the limits of the hybridization steps within the biosensor detection system to establish detection within a matter of two hours, while keeping its high specificity and sensitivity.  These optimization efforts will help use achieve detection within a three and a half hour window.


This DNA-based biosensor can detect fresh, directly extracted DNA from food matrices and provide detection within hours, not days, as current commercially available methods do.  The system is easy to use, inexpensive to fabricate (about $3.00/sample), environmental-friendly when disposed of, requires only inexpensive multimeter for signal read-out, and is expected to be highly portable for field applications.

Key Users

• Customs and Border Protection
• Transportation Security Administration
• Department of Defense
• Emergency Responders
• Food and Agriculture Laboratories
• Food Industry


• Centers for Disease Control and Prevention
• Department of Homeland Security
• U.S. Food and Drug Administration
• USDA Food Safety and Inspection Service
• Food Industry

Project Dates

• 2014-2015

Co-Principal Investigators:

Sylvia Vetrone, Ph.D.
Associate Professor in Biology
Whittier College    

Evangelyn Alocilja, Ph.D.
Professor in Biosystems Engineering
Michigan State University


Download Project Spotlight


This project is funded through the National Center for Food Protection and Defense by the Department of Homeland Security Science and Technology Directorate’s Office of University Programs through Award Number 2010-ST-061-FD0001.