Electrochemical DNA biosensor for potential carcinogen detection in food sample

Abstract

The presence of carcinogens in food is a major food safety concern. A nanocomposite-based electrochemical DNA biosensor was constructed for potential carcinogen detection in food samples by immobilizing amine terminated single stranded DNA onto silica nanospheres deposited onto a screen-printed electrode modified using gold nanoparticles. The effect of three different DNA sequences: 15-base guanine, 24-base guanine and 24-base adenine-thymine rich DNA on carcinogen (formaldehyde and acrylamide) detection was evaluated. The competitive binding of the DNA with the carcinogen and electroactive indicator, Methylene blue (MB) was measured using differential pulse voltammetry. Optimization studies were conducted for MB concentration and accumulation time, DNA concentration, buffer concentration, pH and ionic strength. Overall, the 24-base guanine rich DNA yielded the best results with a detection limit of 0.0001 ppm, linear range between 0.0001 ppm and 0.1 ppm and reproducibility below 5% R.S.D. Finally, the results obtained using the biosensor were validated using Ames test.

Keywords: 23-Aminopropyl-triethoxysilane (PubChem CID: 110154); Acetic acid (PubChem CID: 176); Acetyl acetone (PubChem CID: 31261); Ammonia (PubChem CID: 222); Ammonium Acetate (PubChem CID: 517165); Carcinogens; Di-potassium hydrogen phosphate (PubChem CID: 24450); Electrochemical biosensor; Ethanol (PubChem CID: 702); Glutaraldehyde (PubChem CID: 3485); Gold nanoparticles; Guanine rich DNA; Mercaptoethanol (PubChem CID: 1567); Potassium chloride (PubChem CID: 4873); Potassium dihydrogen phosphate (PubChem CID: 516951); Potassium ferricyanide (PubChem CID: 26250); Silica nanospheres; Sulfuric acid (PubChem CID: 1118); Tetraethoxysilane (PubChem CID: 6517); Toxicity.