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)×10−7 M and a detection limit around 0.55 µM.