Self-cleaning electrochemical sensors
The light will make the sensors clear
ChemPort.Ru based on materials from Chemistry World: Self-cleaning sensors see the lightResearchers from Italy have managed to create a simple and cheap electrochemical sensor that cleans itself when illuminated with ultraviolet light.
This system offers a new way to create self–cleaning electrodes that can be used in a huge number of practical applications - from detecting pollutants in water to measuring the concentration of drugs in the blood.
Nowadays, most chemical and biological sensors are electrochemical devices. The fact that electrochemical methods of analysis are becoming extremely popular is due to the advantages of analytical methods based on the use of electrodes. Recently, electrodes containing nanomaterials have become extremely popular – the high sensitivity and, as a rule, the low cost of such electrodes is due to the high ratio of surface area and volume of nanosystems.
Nevertheless, the main disadvantage of electrodes created using nanomaterials is that they are difficult to keep clean – this circumstance limits the possibilities of practical application of such systems. For example, river water may contain components that can irreversibly damage electrochemical sensors, making it impossible to reuse them. Similarly, it is impossible to reuse electrochemical nanosensors that have been in contact with dopamine, an important neurotransmitter involved in Parkinson's disease.
To solve the problem of irreversible damage to electrodes, Luigi Falciola and his colleagues from the University of Milan have developed an electrochemical sensor, the upper photoactive surface of which consists of titanium oxide; such a surface can be cleaned by ultraviolet light and, thus, used repeatedly. Titanium oxide covers highly ordered silver nanoparticles (they are the core of the system for electrochemical detection of analytes) deposited on a layer of silicon oxide.
Self–cleaning titanium oxide surfaces have recently become commonplace - they are used for the manufacture of self-cleaning windows or self-cleaning coatings for medical instruments. Cleaning of such systems is described by fairly simple chemistry – ultraviolet, the source of which can be both sunlight and artificial UV lamps, initiates photocatalytic processes that contribute to the destruction of organic pollutants. Researchers from the Falciola group decided to apply a similar principle to create a new sensor. According to the researcher, there are a number of examples of self-cleaning electrodes, but the device developed by chemists from Milan is simpler and probably cheaper to manufacture.
During the tests, it was demonstrated that the titanium oxide layer allows not only to clean the electrode, but also protects the electrodes modified by nanoparticles from oxidation and degradation of silver elements. Falchiola says that the new device does not undergo aging, and at the same time, only ultraviolet light is needed to clean it. The researcher suggests that titanium oxide can protect not only silver nanoparticles, but also other nanosystems.
Drawings from the article by Soliveri et al. Self-cleaning properties in engineered sensors
for dopamine electroanalytical detection (Analyst, 2015) – VM.
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