A Novel Sensor Based on Layer-by-Layer Hybridized Phosphomolybdate and Poly(ferrocenylsilane) on a Cysteamine Modified Gold Electrode

A fast and facile electrochemical method for the simultaneous detection of epinephrine, uric acid and folic acid based on ZrO2/ZnO nanocomposites as sensing material

A novel electrochemical sensor based on ZrO₂ and ZnO hybrid nanocomposites was developed for simultaneous determination of epinephrine (EA), uric acid (UA) and folic acid (FA) with the highly selective and ultrasensitive. The nanocomposites have been synthesized by chemical precipitation and thermal calcine method with economical, eco-friendly and practical nature. Their structure and electrochemical properties were investigated by X-ray diffraction (XRD), X-ray photo electron spectroscopy (XPS), scanning electron microscopy (SEM) and electrochemical techniques. The results reveal that the ZrO₂/ZnO nanocomposites can possesses highly exposed catalytic sites, favorable conductivity, and the sensor excellent signal response for EP, UA and FA under the optimal condition. The electrochemical sensing platform has a low detection limit of 0.039 μM, 0.29 μM and 0.037 μM and a wide detection range of 0.8-420 μM, 10-2400 μM and 2-480 μM, respectively. It was also tested with a human blood serum sample at physiological pH with recovery 97.3-103.8% and relation standard deviation less than 5%. It indicates that the electrochemical sensors has a hopeful capacity of extensive applications in bioanalysis and diseases diagnosis.

Printing "Smart" Inks of Redox-Responsive Organometallic Polymers on Microelectrode Arrays for Molecular Sensing

Printing arrays of responsive spots for multiplexed sensing with electrochemical readout requires new molecules and precise, high-throughput deposition of active compounds on microelectrodes with spatial control. We have designed and developed new redox-responsive polymers, featuring a poly(ferrocenylsilane) (PFS) backbone and side groups with disulfide units, which allow an efficient and stable bonding to Au substrates, using sulfur-gold coupling chemistry in a "grafting-to" approach. The polymer molecules can be employed for area selective molecular sensing following their deposition by high-precision inkjet printing. The new PFS derivatives, which serve as "molecular inks", were characterized by ¹H NMR, ¹³C NMR, and FTIR spectroscopies and by gel permeation chromatography. The viscosity and surface tension of the inks were assessed by rheology and pendant drop contact angle measurements, respectively. Commercial microelectrode arrays were modified with the new PFS ink by using inkjet printing in the "drop-on-demand" mode. FTIR spectroscopy, AFM, and EDX-SEM confirmed a successful, spatially localized PFS modification of the individual electrodes within the sensing cells of the microelectrode arrays. The potential application of these devices to act as an electrochemical sensor array was demonstrated with a model analyte, ascorbic acid, by using cyclic voltammetry and amperometric measurements.

A chitosan–Pt nanoparticles/carbon nanotubes-doped phosphomolybdate nanocomposite as a platform for the sensitive detection of nitrite in tap water

A polyoxometalate-based composite film decorated with CNTs and Pt–CHIT NPs was constructed on an electrode using the LBL self-assembly method. It acted as an electrochemical nitrite sensor with greatly enhanced electron transfer ability and sensing performance.