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Institute
The reversible chemosensors to creatinine and desmetryn based on artificial chemoreceptors are described. A grafted photopolymerization combined with a technique of molecular imprinting was used for the receptor layer preparation. After polymer deposition and intensive washing from templates, the electrodes were investigated by impedance spectrometry. Creatinine and desmetryn binding were detected as a decrease in the electrode capacitance. Sensor response to creatining was highly selective. No response to the addition of sodium chloride, creatine, urea or glucose were observed. The electrodes coated with the molecularly imprinted polymers selective to desmetryn displayed specific binding of this herbicide: only small capacitive effects were observed to addition of terbumeton or atrazine, while metribuzine displayed capacitance decrease similar to desmetryn.
The technique of grafting polymerization has been used for preparation of thin films of molecularly imprinting polymers on the surface of polypropylene membranes and on hydrophobized gold electrodes. The herbicide desmetryn was used as a template. The solid supports used were hydrophobic, while the polymer was hydrophilic. The adsorbed layer of benzophenone, irradiated by UV-light, initiated a radical polymerization near the surface. Polymer films were characterized by weighing, contact angle measurements and impedance spectroscopy. The electrodes coated with the molecularly imprinted polymers displayed fairly specific binding of desmetryn, as detected by the decrease in the capacitance of the electrode. Only small capacitive effects were observed on addition of terbumeton or atrazine, while metribuzine displayed capacitance decrease similar to desmetryn.
Electropolymerized molecularly imprinted polymers as receptor layers in capacitive chemical sensors
(1999)
The first application of molecularly imprinted polymers to chemical sensors with capacitive detection is described. The sensitive layer was prepared by electropolymerization of phenol on gold electrodes in the presence of the template (phenylalanine). The insulating properties of the polymer layer were studied by electrochemical impedance spectroscopy. Electrical leakages through the polymer layer were suppressed by deposition of a self-assembled monolayer of mercaptophenol before polymerization and of alkanethiol after polymerization. At the final stage of sensor preparation, the template was removed. The multilayer system obtained displayed a decrease in electrical capacitance on addition of phenylalanine. Only a low response was observed toward other amino acids and phenol.
The first reversible chemosensor to creatinine based on artificial chemoreceptors is described. The receptor layer was prepared by molecularly imprinted photopolymerization of acrylamidomethylpropanesulfonic acid and methylenediacrylamide. The polymer layer was grafted onto the surface of gold electrodes coated with an alkanethiol monolayer. Creatinine binding was detected by a decrease in the electrode capacitance. The sensor response is reversible and highly selective: no response to addition of sodium chloride, creatine, urea or glucose were observed. The detection limit for creatinine is 10 μM which is optimal for medical applications.