E.coli O157:H7 is one of the harmful foodborne pathogenic disease causing bacterium which leads many illnesses and even deaths each year. IDT or IDE (Interdigitated Electrode) based biosensors usually use electrochemical behavior through impedometric detection. In this paper we describe a novel mechanism for E.coli O157:H7 ssDNA target detection via electrical behavior through E.coli O157:H7 probe and (3-Aminopropyl)triethoxysilane (APTES) functionalized Au IDE biosensor. Tween-20 was used as blocking the nonspecific binding on non-immobilized area of the E.coli ssDNA probes. Au IDE was fabricated on the Si substrate using CMOS and conventional photolithographic process. Fabricated Au IDE was physically characterized by using high power microscope (HPM) and scanning electron microscope (SEM). IDE electrode edges were characterized using 3D nano profiler. The E.coli O157:H7 ssDNA probes were used as the receptor to capture the specific target ssDNA and Au IDE was used as the transducer. I-V characteristics were performed for each functionalization step as bare Au IDE, silanization and immobilization. Well functionalized biosensor was hybridized with complementary, non-complementary and single base mismatch ssDNA to confirm the specificity. Sensitivity measurements were done using different concentrations of complementary ssDNA targets from 1fM to 10 µM. The sensitivity and limit of detection (LOD) of the biosensor are 14.3 mAM−1 and 0.8 fM respectively. It was confirmed that Au IDE biosensor shown here is capable to detect specific and low concentrated E.coli O157:H7 ssDNA targets successfully.
