Simple Label-Free DNA Sensor Based on CeO2 Nanorods Decorated with Ppy Nanoparticles

A facile label-free DNA sensor based on cerium oxide nanorods decorated with polypyrrole nanoparticles (CeO2-NRs/Ppy-NPs) matrix has been developed for detection of Salmonella. The sensor was fabricated by hydrothermal synthesis of CeO2-NRs on the microelectrode surface followed by in situ chemical oxidative polymerization of pyrrole on the CeO2-NRs to prepare a CeO2-NR/Ppy-NPs electrode. Single-stranded DNA (ssDNA) sequences were immobilized onto the modified microelectrode by covalent attachment. The properties of the material were explored by field-emission scanning electron microscopy, x-ray diffraction analysis, and Fourier-transform infrared spectroscopy techniques. The response of the DNA biosensor was investigated by electrochemical impedance spectroscopy with [Fe(CN)(6)](3-/4-) as redox probe. The results showed that the response of the DNA biosensor exhibited good linearity within the range of 1.0 x 10(-9) mol L-1 to 1.0 x 10(-6) mol L-1 with sensitivity of 14.7 x 10(6) omega/mol L-1 cm(-1). The limit of detection and limit of quantification of the DNA biosensor were low, with values of 2.86.10(-7) mol L-1 and 9.56.10(-7) mol L-1, respectively.