Advanced Materials: TechConnect Briefs 2015Advanced Materials TechConnect Briefs 2015

Nanocomposite Materials Chapter 6

Analytical system capable of rapidly quantifying food-borne pathogen for food safety and public health

J. Khang, D. Kim, K.W. Chung, J.H. Lee
Luminescent MD, LLC, United States

pp. 448 - 451

Keywords: graphene oxide (GO)/iron nanocomposites, pathogen, E. Coli, aptamer, chemiluminescence

Cost-effective and easy-to-use biosensor was developed for the rapid quantification and monitoring of Escherichia (E.) Coli O157:H7 in sample using E. Coli O157:H7 aptamer, graphene oxide (GO)/iron nanocomposites, and guanine chemiluminescence detection. E. Coli O157:H7 aptamer-conjugated 6-carboxyfluorescein (6-FAM) with excellent specificity captured E. Coli O157:H7 in a sample when the mixture was incubated for 1 hour at 37 C. Free E. Coli O157:H7 aptamers remaining in sample after the incubation were removed with GO/iron nanocomposites based on the principle of π-π stacking interaction between free aptamer and GO/iron nanocomposites. Then, E. Coli O157:H7 bound with aptamer-conjugated 6-FAM in sample emitted strong light when guanine chemiluminescent reagents (e.g., 3,4,5-trimethoxylphenylglyoxal hydrate, Tetra-n-propylammonium hydroxide) were added in the sample. The strength of light emitted in guanine chemiluminescence reaction was proportionally enhanced with the increase of E. Coli O157:H7 concentration. The limit of detection (LOD) of biosensor capable of quantifying E. Coli O157:H7 with good accuracy, precision, and reproducibility was as low as 4.5 × 103 cfu/ml. We expect that the rapid analytical system can be applied in the field of food safety as well as public health.