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Development of handheld DNA Sensor for foodborne pathogen detection: Fundamental factors & Challenges

Vijayalakshmi Velusamy Khalil Arshak 1Olga Korostynska Kamila Oliva-Stasiak Catherine Adley 

1. University of Limerick (UL), Plassey Technological Park, Limerick 02098, Ireland


A range of sophisticated technologies to detect the contaminants in food are available. However, foodborne outbreaks from microbial contamination, toxins and chemicals are common in many countries. The electrochemical devices have received significant attention in the development of DNA biosensors. The use of a handheld DNA biosensor platform is essential for the real-time detection of specific pathogens from mixed food matrices.

The current study is aimed at developing a highly sensitive (< 1µg/mL) and stable method for the electrochemical detection of foodborne pathogens. The electrochemical technique cyclic voltammetry was used as a method of transduction and the conducting polymer, while polypyrrole was used as a platform for immobilizing DNA on the gold disc electrodes (2mm diameter).

The electrical conduction in polypyrrole is the result of electron movement within delocalized orbitals and positive charge defects which are known as polarons. Both monovalent (Na, K) and divalent electrolytes (Ca2+, Cu2+, Mg2+, Mn2+) are used as dopant for the polymerisation of polypyrrole. These dopant materials (electrolytes) are naturally found in the bacterial cells and have strong affinity to the DNA backbone. The rate of electropolymerization of pyrrole is varied with the electrolyte concentration (0.1 M – 0.5 M), applied voltage (0.5-1V), and monomer concentration (0.01 M – 0.1 M). The electrochemical entrapment was chosen as an immobilization method because it is rapid, simple, label free and is a one-step technique. Bonding efficiency and the stability of the DNA immobilised on the polypyrrole film obtained from various electrolytes are studied. Furthermore, the main factors to be considered while designing a DNA biosensor and the challenges for the real time detection of bacterial pathogens is also discussed.

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Presentation: Oral at E-MRS Fall Meeting 2009, Symposium F, by Khalil Arshak
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-05-21 18:22
Revised:   2009-06-07 00:48