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In this research, an efficient fabrication process of conducting polypyrrole (PPy)/silicon nitride (Si3N4) hybrid materials were developed in order to be employed as transducers in electrochemical sensors used in various environmental and biomedical applications. The fabrication process was assisted by oxidative polymerization of pyrrole (Py) monomer on the surface of Si/SiO2/Si3N4 substrate in presence of FeCl3 as oxidant. To improve the adhesion of PPy layer to Si3N4 surface, a pyrrole-silane (SPy) was chemically bonded through silanization process onto the Si3N4 surface before deposition of PPy layer. After Py polymerization, Si/SiO2/Si3N4-(SPy-PPy) substrate was formed. The influence of SPy concentration and temperature of silanization process on chemical composition and surface morphology of the prepared Si/SiO2/Si3N4-(SPy-PPy) substrates was studied by FTIR and SEM. In addition, the electrical properties of the prepared substrates were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that the best silanization reaction conditions to get Si/SiO2/Si3N4-(SPy-PPy) substrate with high PPy adhesion and good electrical conductivity were obtained by using SPy at low concentration (4.3 mM) at 90°C. These promising findings open the way for fabrication of new hybrid materials which can be used as transducers in miniaturized sensing devices for various environmental and biomedical applications. [ABSTRACT FROM AUTHOR]

Poly(pyrrole)-nanowires (PPy-NWs) were efficiently printed by using nano printing on flexible thermoplastics, and then used to device an impedimetric immunosensor. The present pioneering technology allow to create high sensitive and disponsable immunosensor devised using a low cost and simple fabrication. The innovative nanocontact printing uses a PDMS stamp replicated from a CD mold. The PPyNW printing uses controlled chemical polymerization to print PPy-NWs on poly (ethylene terephthalate) and polyether ether ketone surfaces. Atomic force microscopy analysis of PPyNW revealed a width, height and a separation length of 125 ± 8 nm, 377 ± 5 nm and 172 ± 4 nm, respectively. The PPy-NWs were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The XPS results evidenced the covalent bonding between the thermoplastic surface and the PPyNWs. As a final point, the immunosensor was tested for the quantification of Interleukin 6 recombinant human (IL6, Ag) using EIS. The PPy-NWs were functionalized via diazonium coupling reaction and carbodiimide crosslinker chemistry for the immobilization of Anti-human IL-6 monoclonal antibodies (IL6 mAb’s). The developed immunosensor exhibited a sensitivity of 0.013 (pg/mL) −1 (linear fitting at R 2 = 0.99) and limit of detection (LOD) of 0.36 pg/mL in a linear range of 1–50 pg/mL for Ag IL-6, with a relative standard deviation percentage (RSD%) at 7.6%. [ABSTRACT FROM AUTHOR]