Imprinted electrode surfaces

Electrochemical sensors using surfaces modified with imprinted polymers are finding increasing use in analytical chemistry [46]. Electrode surfaces can be modified in a similar way to the crystal surface of a QCM. The application of imprinted polymer particles as an ink to the surface of an electrode is a convenient way of preparing an imprinted surface and can provide a cheap and relatively simple route to prepare a sensing device. Imprinted electrode surfaces have also been prepared... 

The histamine [131], adenine [132] and dopamine [133] amines are electroactive in the positive potential range, in which the thiophene is electropolymerized. Therefore, these amines could be oxidized at the electrode surface in the course of deposition of the MIP film. That way, products of these oxidations might be available in the electrode vicinity for imprinting rather than the desired pristine... 

Prasad, B., and Pandey, 1. (2013). Electrochemically imprinted molecular recognition sites on multiwalled carbon-nanotubes/pencil graphite electrode surface for enantioselective detection of D- and L-asparticacid, ElecUvchinLAc 88, 24-34. 

A broader range of sensor devices has been developed, where the sensor response is modulated by the presence of an imprinted polymer, or an imprinted surface. Perhaps the simplest way of preparing an imprinted surface is in the use of self-assembled monolayer (SAM) techniques. A cholesterol-specific SAM was prepared by Piletsky et al. [44], in which a gold electrode was treated with a solution of cholesterol and hexadecanethiol in methanol. After the SAM had been established, the template was removed, leaving cholesterol-shaped cavities in the imprinted surface. Amperometric measurements were then used to investigate the sensitivity of the electrode towards cholesterol. It was found that the unmodified electrode, and the imprinted electrode displayed the same peak current. However, exposure of the imprinted electrode to a solution of template caused a decrease in... 

The electrochemical sensors with chemical recognition applied to pesticides analyses take advantage of the analytical features of the differential pulse voltammetry, square-wave voltammetry, and stripping voltammetry [26-30], which allow pesticides detection at residues levels. Current efforts are directed toward sensitivity and selectivity improvement by chemical modification of the electrode surface by molecularly imprinted polymers and micro- and nanostructured materials [31]. 

A sensor for the detection of Uric acid was proposed in (Yu J.C.C. Lai, 2006) by polymerization of polymethacrylic acid on the surface of vinyl-functionalized CNTs in the presence of the template. The MIP adsorbs more Uric acid than NIP and the imprinting efficiency was found to be about 4.41. The MIP modified MWCNTs can be deposited on the MWCNTs electrode surface and used for the electrochemical detection for the template. The differences of adsorption amounts between MIP and NIP electrodes were determined by CVs with different adsorption times. The adsorption reached saturation after 5min of adsorption and the result was close to the rebinding experiments. The sensitivities of the MIP and NIP modified electrodes were about 11.03 and 5.39 mAM i cm"2, respectively, and the difference mainly came from the affinity cavities which were created by the imprinted template. 

Zhang, Z., Nie, L., and Yao, S. (2006) Electrodeposited sol-gel-imprinted sensing film for cytidine recognition on Au-electrode surface. Talanta, 69, 435-442. 

An early attempt to make a real electrochemical sensor based on a molecularly imprinted methacrylate polymer utilised conductometric measurements on a field-effect capacitor [76]. A thin film of phenylalanine anilide-imprinted MAA-EDMA copolymer was deposited on the surface of semiconducting p-type silicon and covered with a perforated platinum electrode. An AC potential was applied between this electrode and an aluminium electrode on the back side of the semiconductor and the capacitance measured as a function of the potential when the device was exposed to the analyte in ethanol. The print molecule could be distinguished from phenylalanine but not from tyrosine anilide and the results were very variable between devices, which was attributed to difficulties in the film production. The mechanism by which analyte bound to the polymer might influence the capacitance is again rather unclear. 

Zhou Y, Yu B, Shiu E, Levon K (2004) Potentiometric sensing of chemical warfare agents surface imprinted polymer integrated with an indium tin oxide electrode. Anal Chem 76(10) 2689-2693... 

Ethylene glycol dimethacrylate (EDMA)-methacrylic acid (MAA) copolymer-based imprinted polymer particles were mixed with poly(vinyl chloride) in THF, and the solution was then spread on the electrode of the QCM by spin coating. After evaporation of the THF, the polymer particles were immobilized on the surface. A phenobarbital-imprinted QCM sensor prepared in this way worked in ethanol [1], while epinephrine- and caffeine-imprinted QCMs worked in buffer solutions (pH 6.0 and pH 8.0, respectively) [2, 3],... 

AMP-imprinted polyion complex layers were deposited on the electrode of a QCM [7]. At first, an anionic surface was prepared by exposing 3-mercaptopropionic acid. Then cationic polyion-containing ben-zeneboronic acid residues and anionic polyion-containing quaternary ammonium residues were alternatively deposited on it with a template molecule, adenosine monophosphate (AMP). When AMP was re-bound to the polyion complex, the shrinking of the imprinted polyion complex was induced, causing the frequency to change. 

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