A Polymer-Based Electrochemical DNA Biosensor for Salmonella: Preparation, Characterization and Calibration

In this paper, we present the results of the use of bifunctional polymeric films of polystyrene (10.3 KD-49.5 KD) to anchor oligo sequences of various lengths (15, 35 and 70-mer). The polymers were prepared by radical polymerization with 4,4'-azobis(4-cyanovaleric acid) as initiator and 3-Carboxy PROXYL to control the molecular weight and polydispersity. They were further modified with N-hydroxysuccinimide to anchor the (5'-AmMC12) oligos. The anchoring reaction was done on a polymer-modified glassy carbon electrode. The probes were hybridized with their ferrocene-labeled complementary sequences. The hybridization reaction was followed by Osteryoung square wave voltammetry (OSWV). The calibration curve showed a narrow and sharp linear range between (5.7-8.0) x 10(-7) M and a detection limit around 0.55 mu M.