Pedot:Pss–Modified Platinum Microelectrodes for Measurements in Aqueous Media: Effect of Polymer Surface Area on Long-Term Anodic Peak Current Stability (original) (raw)
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IIUM Engineering Journal
Contamination of drinking water by hazardous agents is becoming a serious global threat, so it is necessary to develop more efficient sensing technologies for applications in liquid media. The limited working lifetime of electrochemical biosensors, especially when measurements are made continuously in liquid media, remains an unsolved challenge. We studied the effect of PEDOT:PSS surface area on platinum microelectrodes with respect to electrode ability to conduct reversible ion-to-electron transduction in liquid media. Electropolymerization of 3,4-ethylenedioxythiophene:poly(styrene sulfonate) EDOT:PSS to poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was conducted on microplatinum electrodes 5 and 10 mm long using a galvanostatic mode. Cyclic voltammetry was used to determine capacitive peak current; higher peak current indicates higher redox capacitance. Field-emisison scanning-electron microscopy was used to study the surface morphology of the PEDOT:PSS tra...
Construction, Activation and Modification of Platinum Microelectrodes for (Bio)Sensors Development
In this paper we investigate the possibilities to use microelectrodes for the analysis of two biological significant compounds: L-cysteine (L-Cys) and hydrogen peroxide and subsequently This paper presents the construction and surface activation of vacuum-deposed microelectrodes tested for the detection of biologically significant compounds like hydrogen peroxide and L-cysteine. It was demonstrated that the platinum working electrode surface etching by cyclic voltammetry in sulfuric acid aqueous solution lead to a significant amperometric analytical signal increase. The microelectrodes were tested as transducers for biosensor development by immobilizing acetylcholinesterase using diazonium chemistry.
Sensors and Actuators B: Chemical, 2004
An aqueous dispersion of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS) was cast on screenprinted gold substrates. PEDOT(PSS) was ionically (physically) crosslinked by multivalent cations, including Mg 2+ ,Ca 2 + ,Fe 2 + / 3 + and Ru(NH 3 ) 6 2+/3+ to form a hydrogel in order to decrease the water solubility of the PEDOT(PSS). The resulting Au/PEDOT(PSS) electrodes were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and energy-dispersive X-ray analysis (EDXA). Ionic crosslinking of PEDOT(PSS) with Fe 2+/3+ and Ru(NH 3 ) 6 2+/3+ was faster than with Mg 2+ and Ca 2+ ions and resulted in PEDOT(PSS) films that were less soluble in water. Among the multivalent cations tested, Ru(NH 3 ) 6 2+/3+ resulted in PEDOT(PSS) films with the most stable potential. Incorporation of Ru into PEDOT(PSS) was shown by EDXA. Based on CV and EIS, ionic crosslinking of PEDOT(PSS) with the electroactive Ru(NH 3 ) 6 2+/3+ was found to increase the bulk redox capacitance of the PEDOT(PSS) film, compared to ionic crosslinking with electroinactive Mg 2+ ions. Potentiometric measurements showed that PEDOT(PSS) ionically crosslinked with Ru(NH 3 ) 6 2+/3+ was less sensitive to CO 2 (pH) than the bare Au substrate. The Au/PEDOT(PSS) electrodes were found to work well as ion-to-electron transducer (solid contact) in all-solid-state K + -ion-selective electrodes (ISEs).
Sensors, 2019
Nanostructured materials have attracted considerable interest over the last few decades to enhance sensing capabilities thanks to their unique properties and large surface area. In particular, noble metal nanostructures offer several advantages including high stability, non-toxicity and excellent electrochemical behaviour. However, in recent years the great expansion of point-of-care (POC) and wearable systems and the attempt to perform measurements in tiny spaces have also risen the need of increasing sensors miniaturization. Fast constant potential electrodeposition techniques have been proven to be an efficient way to obtain conformal platinum and gold nanostructured layers on macro-electrodes. However, this technique is not effective on micro-electrodes. In this paper, we investigate an alternative one-step deposition technique of platinum nanoflowers on micro-electrodes by linear sweep voltammetry (LSV). The effective deposition of platinum nanoflowers with similar properties t...
Intelligent System and Applied Material, Pts 1 and 2, 2012
Poly(3,4-ethylenedioxy-thiophene):polystyrenesulfonic acid (PEDOT:PSS), a commercially available aqueous conducting polymer, as the electrode modified material for the development of sensing and biosensing devices has not been widely reported due to its swelling and disintegration in aqueous solution. For this purpose, A poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) modified electrode was facilely fabricated for the electrochemical detection of catechol. 1-butyl-3-methylimidazolium hexafluorophosphate, one of hydrophobic ionic liquids, was used for secondary dopant and enhancer to improve the water-resistance and the electrochemical properties of PEDOT:PSS polymer film. The as-prepared PEDOT:PSS modified electrode exhibited the pronounced water-stability and good sensing performance, which make PEDOT:PSS as an interesting candidate of the electrode modified material for application in sensing and biosensing devices in the near future.
Biosensors and Bioelectronics, 2004
Potentiometric pH sensors based on linear polyethylenimine (L-PEI) and linear polypropylenimine(L-PPI), two synthetic enzymes and biocompatible polymers, films were prepared by electropolymerization of three different monomers: ethylenediamine (EDA), 1,3-diaminopropane (1,3-DAP) and diethylenetriamine (DETA) in order to be used in clinical, dermatological and biological applications, such as in vivo analysis. In a first step a biosensor was tested which consisted in a platinum wire protruded from glass sheath. The polymer film coated on these platinum electrodes showed good linear potentiometric responses to pH changes from pH 3 to 10. Resulting electrodes present both good reversibility and good stability versus time. The effect of the different polymer film thicknesses to potentiometric responses was also studied. This study allowed us to develop a miniaturized pH biosensor in the second step. This sensor was fabricated using photolithography, followed by sputtering and lift-off processes, and it included an electronic detection system. We have also successfully studied the potentiometric responses to pH changes of this device over a period of 1 month, and so we propose this new pH microbiosensor as an alternative to classical pH sensors currently used in dermatology.
Electroanalysis, 2013
Thin layers of the thermo sensitive cross-linked poly(N-isopropylacrylamide) gel were anchored on the surface of platinum micro-and regular-electrodes. No preliminary functionalization of the surface was used; just electroformation of radicals at the surface led to strong binding of the polymer net. The electroanalytical investigation was focused on how the volume phase transition affects the height of the voltammetric peak of a model compound, 1,1'ferrocenedimethanol. The changes in the oxidation peak current of the electroactive compound upon switching temperature were perfectly reversible. Additionally, it was found that these changes were very fast and the polymer film was very stable. Very good adhesion of poly(N-isopropylacrylamide) gel to platinum surface and excellent reversibility of the shrinking/swelling process (volume phase transition) may produce new possibilities in electroanalysis.
Development of miniaturized pH biosensors based on electrosynthesized polymer films
Analytica Chimica Acta, 2007
A new type of pH biosensor was developed for biological applications. This biosensor was fabricated using silicon microsystem technology and consists in two platinum microelectrodes. The first microelectrode was coated by an electrosynthesized polymer and acted as the pH sensitive electrode when the second one was coated by a silver layer and was used as the reference electrode. Then, this potentiometric pH miniaturized biosensor based on electrosynthesized polypyrrole or electrosynthesized linear polyethylenimine films was tested. The potentiometric responses appeared reversible and linear to pH changes in the range from pH 4 to 9. More, the responses were fast (less than 1 min for all sensors), they were stable in time since PPy/PEI films were stable during more than 30 days, and no interference was observed. The influence of the polymer thickness was also studied.