rapid and sensitive electrochemical detection of dna with silvernanoparticle dispersed poly (9, 9-dioctylfluorene-ran-phenylene) nanocomposites

In this study a sensitive electrochemical sensor for the detection of e.coli has been developed using silvernanoparticle (ag) embedded poly (9, 9-dioctylfluorene-ran-phenylene) (cfp) nanocomposite as a conductiveplatform and dna hybridization technique. the new polymer was synthesized from 9, 9-dioctylfluorene and1, 3-dichlorobenzene and biphenyl through friedel crafts alkylation reaction and the synthesized polymeras well as the ag nanoparticles loaded composite were characterized using fourier-transform infraredspectroscopy (ftir), nuclear magnetic resonance (nmr), x-ray powder diffraction (xrd), scanningelectron microscopy (sem) and transmission electron microscopy (tem) analysis. for accurate andrapid label-free electrochemical detection of pathogenic bacteria such as e.coliwas studied by spin coatingthe nanocomposite suspension into indium tin oxide electrode (ito) followed by the immobilization ofaminoterminated oligonucleotide (pdna), as probe. the resultant pdna/ag-cfp/ito biosensor was thenused to detect ssdna, cleaved from genomic dna of e.coli, using differential pulse voltammetry (dpv)technique. under optimal experimental conditions, the biosensor could detect ssdna in a wide linear rangefrom 1 × 10^-15 m to 1 × 10^-22 m with a lowest detection limit of 1 × 10^-22 m.