A facile electrochemical sensor was developed by electrochemical deposition of PtIr nanoparticles on poly(3,4ethylenedioxythiophene) (PEDOT) modified carbon fiber paper electrode (CFP). The modified electrodes were characterized by Field emission scanning electron microscopy (FESEM) with energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), RAMAN spectroscopy, Fourier transform infrared spectroscopy (FTIR) and electroanalytical techniques. PtIr-PEDOT modified CFP electrode was used successfully in the determination of an anti-hypertensive prodrug Olmesartan medoxomil (OM) at femtomolar (fM) level for the first time. Under optimal conditions, the prepared electrochemical sensor has shown broad linear range between 0.001 pM and 0.220 pM and superior detection limit of 3.42 fM was observed based on Differential pulse voltammetric (DPV) study. In addition, the designed electrochemical sensor was successfully demonstrated as a novel platform in the electrochemical determination of OM in human urine and pharmaceutical samples.

Development of pressure sensors which display high sensitivity, and are flexible, inexpensive, and easy to manufacture has drawn significant interest due to their diverse applications such as tactile skin sensors (e.g.''electronic skin''), pulse detectors, speech recognition elements, and others. While varied technologies and molecular constructs have been demonstrated for pressure sensing, considerable conceptual and technical challenges still hamper broad implementation of many such systems. A novel flexible piezoresistive sensor comprising a conductive Au-coated elastomeric polymer sponge is presented. The piezoresistive sponge is prepared through a simple chemical route in which Au nanoribbons are spontaneously grown upon an aminefunctionalized polyurethane framework. The Au nanoribbon layer coats the internal surfaces within the polymer pore network, resulting in electrical current modulation upon pressure application/release through changes in the overall contact areas between the conductive surfaces. The Au-polyurethane piezoresistive sensor exhibits excellent functionalities, including enhanced sensitivity, low detection threshold, high fidelity, and physical stability. Application of the sensor is demonstrated for high resolution monitoring of wrist arterial pulses. Experimental section MaterialsHAuCl 4 Á3H 2 O, KSCN, branched polyethylenimine (b-PEI) with average M w B 25 000 by LS average M n B 10 000 by GPC, N-hydroxysuccinimide (NHS), 2-(N-morpholino)ethane sulfonic acid (MES) and

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Polydiacetylenes (PDAs) constitute a family of conjugated polymers exhibiting unique colorimetric and fluorescence transitions, and have attracted significant interest as chemo- and biosensing materials. We spin-coated PDA films upon poly(methyl methacrylate) (PMMA), and investigated the photophysical properties and sensing applications of the new PDA configuration. Specifically, the as-polymerized blue PDA layer underwent distinct transformations to purple, red, and yellow phases, which could be quantified through conventional color scanning combined with application of image analysis algorithms. Furthermore, we recorded a reversible red-purple PDA transition that was induced by ultraviolet irradiation, a phenomenon that had not been reported previously in PDA film systems. We show that distinct color and fluorescence transitions were induced in the PMMA-supported PDA films by amphiphilic substances-surfactants and ionic liquids-and that the chromatic transformations were correlated to the analyte structures and properties. Overall, this study presents a new chromatic PDA film system in which noncovalent interactions between the PMMA substrate and spin-coated PDA give rise to distinct chromatic properties and molecular sensing capabilities.