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Biocompatible polymers, such as poly(ethylene glycol) (PEG), are of great significance in the development of bio-interfaces and biosensors, as they possess excellent biocompatibility and are easy for modification. A novel highly biocompatible polymer composite was synthesized herein through electrochemical polymerization of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and a PEG derivative, 4-arm PEG terminated with thiol groups. The electrodeposited conducting polymer composite of PEG doped PEDOT (PEDOT/PEG) exhibited flake-like nanostructure, large surface area and outstanding stability. In order to further immobilize antibodies, gold nanoparticles (AuNPs) were introduced to the PEDOT/PEG composite surface through their unique interaction with the thiol groups. AuNPs modified PEDOT/PEG provided a desirable support for the immobilization of various biomolecules such as antibodies for alpha fetoprotein (AFP), a vital tumor biomarker for liver cancer. The fabricated AFP biosensor demonstrated favorable selectivity, high sensitivity, and ultralow detection limit. Furthermore, owing to the presence of PEG polymers that are highly hydrophilic, such AuNPs/PEDOT/PEG based AFP biosensor also exhibited good anti-fouling ability, and it was capable of assaying target AFP in 10% (V/V) human serum samples, indicating highly feasible potential for clinical diagnosis. [ABSTRACT FROM AUTHOR]

Biosensors have tremendous revolutionary potential for the precise location and rapid detection of biomarkers for human disease. However, the minimization of nonspecific protein adsorption interactions and surface contamination is critical for their application in complex media. We report herein, the antifouling interface was constructed by electrochemical copolymerization of poly (3,4-ethylenedloxythlophene) (PEDOT) and glycyrrhiza polysaccharide (GPS). Hydrophilic PEDOT/GPS can reduce the interference and nonspecific adsorption of biological protein macromolecules, which has been verified by electrochemical and fluorescent characterization. Gold nanoparticles (AuNPs) were subsequently modified onto PEDOT/GPS surface to attach biomacromolecules containing thiol groups. MicroRNA, the promising biomarker of a large numbers of genetic diseases, was used as the testing model. Due to the robust antifouling capability of PEDOT/GPS as well as high biocompatibility of GPS/AuNPs, the fabricated biosensor based on PEDOT/GPS/AuNPs demonstrated excellent sensing performance, such as a wide detection range (0.01 nM–10 nM), a low detection limit (300 fM) and high reproducibility, showing great potential of medical applications. Glycyrrhiza polysaccharide (GPS) and poly (3,4-ethylenedloxythlophene) (PEDOT) was constructed by electrochemical copolymerization. Hydrophilic PEDOT/GPS can reduce the interference and nonspecific adsorption of biological protein macromolecules. The biosensor based on PEDOT/GPS/AuNPs demonstrated excellent sensing performance, such as wide detection range, low detection limit and high reproducibility. Image 1 • Conducting polymer PEDOT/GPS was prepared by a simple electrochemical way. • The PEDOT/GPS demonstrated good conductivity and antifouling property. • The low fouling, label-free biosensor based on PEDOT/GPS has been constructed for MicroRNA. • The biosensor based on PEDOT/GPS/AuNPs has shown excellent sensing performances. [ABSTRACT FROM AUTHOR]

Conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) possesses high electrical conductivity but limited catalytic activity, and doping with suitable nanomaterial to fabricate multifunctional electrical substrate is an ideal approach to broaden the application of PEDOT. Herein, Au@graphene (AG) core-shell nanoparticles with high conductivity, catalytic activity and stability, were synthesized and doped into PEDOT to build PEDOT/AG nanocomposite material by a facile electrodeposition method. The PEDOT/AG composite exhibited high conductivity and excellent catalytic activity toward the redox of paracetamol, and owing to the presence of AG nanoparticles, the electrochemical signals and peak profiles of paracetamol at the PEDOT/AG modified electrode were significantly improved. Under optimum conditions, the PEDOT/AG modified electrode exhibited high sensitivity to paracetamol over a wide linear range of concentrations from 0.15 μM to 5.88 mM, with a detection limit of 41 nM (S/N = 3). Furthermore, the fabricated sensor exhibited high selectivity and long-term stability, and was capable of detecting paracetamol in real pharmaceutical samples with satisfying accuracy. [ABSTRACT FROM AUTHOR]

Conducting polymer polyaniline (PANI) nanowire arrays were electrochemically in situ synthesized on the surface of glassy carbon electrodes, which were modified with self-assembled multi-walled carbon nanotubes (CNTs) networks. The ordered PANI nanowire arrays and CNTs networks were integrated to create 3D nanostructured PANI/CNTs composites. Owing to their unique microstructure and conductivity, the PANI/CNTs nanocomposite exhibited excellent electrical properties such as remarkable supercapacitor performance and catalytic activity toward nitrite electrochemical reduction. It was found that the PANI/CNTs nanocomposite was capable of delivering high specific capacitance and showed excellent cycling stability. Moreover, it could be utilized as an electrochemical sensor for the detection of nitrite, with an outstanding sensitivity, low detection limit (6.1 μM, a signal to noise ratio of 3) and a fast response time of less than 5 s. [ABSTRACT FROM AUTHOR]