Electro-templating of prussian blue nanoparticles in PEDOT:PSS and soluble silkworm protein for hydrogen peroxide sensing.

Herein, we demonstrate a high-accuracy H2O2 selective organic-inorganic 3D-heterointerface based on catalytically in-situ reduced Prussian-blue nanoparticles (PBNPs), Poly (3,4-ethylene dioxythiophene):poly (styrene sulfonic acid) (PEDOT:PSS) and water-soluble Silkworm protein (SWp). PBNPs were immobilized on an indium tin oxide-coated glass (ITO) electrode through the electrochemical polymerization process of PEDOT:PSS and the yielding intertwining composite was templated by the use of SWp, simultaneously. Since PSS and SWp act as poly-anionic and poly-cationic charge compensating elements, the sensing system's potential cycling and amperometric response stability have been significantly enhanced thanks to the arising physical blockage effect. Constructed sensing system showed a substantially high sensitivity (1031.7 µA mM-1 cm-2) and a low limit of detection value (LOD, 0.29 µM) between 1 and 130 µM H2O2. Eliminating the possible signal disruptions by common anion and cations in tap water, the (PEDOT:PSS:PB):SWp interface successfully selected H2O2 between the concentration of 10-40 µM with high recovery and relatively low RSDs oscillating between 94.2-110.9% and 2.9-5.1%, respectively. It is thought that the proposed heterointerface can be used in the field of sensor, biosensor and fuel cell systems run by H2O2 assay based on 3D scaffold-templated conductive polymer-PBNPs network.

Enzyme-free detection of hydrogen peroxide with a hybrid transducing system based on sodium carboxymethyl cellulose, poly(3,4-ethylenedioxythiophene) and prussian blue nanoparticles.

Herein, we report a two-layered hybrid catalytic interface composed of carboxymethyl cellulose (CMC), poly (3,4-ethylene dioxythiophene) (PEDOT), Prussian blue (PB) nanoparticles and Nickel-Hexacyanoferrate (Ni-HCF) layer for the enzyme-free detection of hydrogen peroxide (H2O2). Whereas the first layer, CMC:PEDOT:PB, is responsible for generating amperometric signals toward H2O2, Ni-HCF on CMC:PEDOT:PB layer is playing an active role as an operational stability-enhancer. In the study, where the systematic optimization of the sensor electrode is presented using cyclic voltammetry (CV), amperometry and electrochemical impedance spectroscopy (EIS) technique, the physical and chemical properties of the hybrid composite systems constructed is also supported by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) techniques. The amperometric signal generation of the H2O2 sensor was linear between 1 and 100 µM (R2 = 0.999) with a sensitivity of 416.11 µA mM-1cm-2, providing a limit of detection (LOD) of 0.33 µM. The sensing system, which was not affected by the various interfering molecules, creates a successful sensor platform for H2O2 measurements in tap water with a high recovery value between 94.0% and 110.5% and relatively small RSD in the range of 0.4-5.2%.

Processable and nanofibrous polyaniline:polystyrene-sulphonate (nano-PANI:PSS) for the fabrication of catalyst-free ammonium sensors and enzyme-coupled urea biosensors.

Tailoring conducting polymers (CPs) such as polyaniline (PANI) to deliver the appropriate morphology, electrochemical properties and processability is essential for the development of effective polymer-based electrochemical sensors and biosensors. Composite PANI electrodes for the detection of ammonium (NH4+) have been previously reported, but have been limited by their reliance on the electrocatalytic reaction between NH4+ and a metal/nano-catalyst. We report an advanced processable and nanofibrous polyaniline:polystyrene-sulphonate (nano-PANI:PSS) as a functional ink for the fabrication of catalyst-free NH4+ sensors and enzyme-coupled urea biosensors. The PSS provides both a soft-template for nanofibre formation and a poly-anionic charge compensator, enabling the detection of NH4+ based on an intrinsic doping/de-doping mechanism. The nanostructured morphology, chemical characteristics and electrochemical properties of the nano-PANI:PSS were characterised. We fabricated 3D-hierarchical sensor interfaces composed of inter-connected nano-PANI:PSS fibres (diameter of ~50.3 ± 4.8 nm) for the detection of NH4+ with a wide linear range of 0.1-11.5 mM (R2 = 0.996) and high sensitivity of 106 mA M-1 cm-2. We further demonstrated the coupling of the enzyme urease with the nano-PANI:PSS to create a urea biosensor with an innovative biocatalytic product-to-dopant relay mechanism for the detection of urea, with a linear range of 0.2-0.9 mM (R2 = 0.971) and high sensitivity of 41 mA M-1 cm-2. Moreover, the nano-PANI:PSS-based sensors show good selectivity for the detection of NH4+and urea in a urine model containing common interfering molecules. This processable and fibrous nano-PANI:PSS provides new advance on CP-based transducer materials in the emerging field of printed organic sensors and biosensors.