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Electrochemically active nanostructured polypyrrole (PPy) coated with polyaniline (PANi) was deposited on the electrode followed by the gluteraldehyde (GA) attachment for grafting 5'-amine modified single strand DNA (ssDNA) to form the PPy-PANi-GA-ssDNA and DNA hybridization in phosphate buffer solution. Differential pulse voltammetry (DPV) was used to monitor the hybridization events with methylene blue as electrochemical indicator. The exhibited sensitivity and selectivity was attributed to 10 the nanotubical structure of PPy-PANi and 472 times greater conductivity than the conventional PPy-PANi composite. The biosensor has been characterized by Cyclic Voltammetry (CV), Electrochemical Impedance (EI), FT-IR, Differential Pulse Voltammetry (DPV) and Scanning Electron Microscope (SEM). This sensor showed good stability, selectivity and higher sensitivity than the MWCNT/AgNPs and PPy/MWCNT/AuNPs composites reported previously. The dynamic range observed was 1 ×10 -9 to 1 15 × 10 -13 M, with a lower detection limit 50 fM. 65 Furthermore, the preparation of nanostructure of conducting polymer is another issue currently limiting their application in biosensor. In general, hard-template and soft-template methods are widely employed in the synthesis of conducting polymer nanostrucutres. However, simple, efficient, controlled and large-70 scale synthesis method for preparation of conducting polymer nanostructure are still lacking.

The electrochemical behavior of riboflavin (RF) at a glassy carbon electrode modified with α-Fe2O3/MWCNT/AuNPs was investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV).

We report the easy fabrication of gold nanoparticles (AuNPs) functionalized poly(3,4ethylenedioxythiophene) (PEDOT) film on a glassy carbon (GC) electrode for label free DNA sensing in the presence of a [Ru(NH 3 ) 6 ] 3+ (RuHex) redox probe in Tris-HCl buffer. Cyclic voltammetry (CV) and chronocoulometry (CC) techniques were employed for interrogating the electrochemical behavior of the modified GC electrode and DNA sensing. Incorporation of the AuNPs in the PEDOT matrix induces 10fold increase in conductivity and also eliminates the direct functionalization of the native polymer for DNA attachment. The modified films were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy, Atomic Force Microscopy (AFM), CV and CC techniques. The observed dynamic detection range is 1.0 Â 10 À13 to 1.0 Â 10 À15 M, with the lowest detection limit (3s/b) of 2.6 Â 10 À16 M.

We have found that magnetic α-Fe2O3 nanocubes exhibit an intrinsic catalytic activity toward the electrochemical sensing of dopamine (DA) and uric acid (UA) in the presence of ascorbic acid.

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In this study, marigold flower-like self-assembled β-NiS (nickel sulfide) nanosheets were grown on rGO (reduced graphene oxide) by a single-step hydrothermal process and then gold nanospheres (AuNS) were electrochemically deposited on the β-NiS@rGO nanostructures.