UA researchers develop more effective biosensors for monitoring glucose levels
The challenge is using materials having a high affinity with this substance and avoid false positives
UA researchers during the screening of substances and selective electrochemical sensor scheme
Alicante. Friday, 13 November 2015
The development of analytical small cheap, portable, reliable, and easy to use devices to determine a particular parameter is more and more necessary all the time. In this context, the University of Alicante Department of Physical Chemistry Research Group of Electrocatalysis and Polymer Electrochemistry has developed sensors and electrochemical biosensors for the detection of substances of medical and biological interest, such as neurotransmitters (dopamine, epinephrine, norepinephrine, etc. .) and various metabolites such as glucose, vitamin C, uric acid, and others.
At present, there are various electrochemical sensors that cause an interaction between an electrode and the molecule to be detected. The intensity of the electric current generated by this reaction is related to the amount of the molecule in the sample.
The greatest interest of the development of a sensor of this type is to be able to apply it directly on physiological fluids (blood, urine, saliva, etc.). But the greatest difficulty is to obtain correct analysis is the presence of other chemical species in these fluids interfering in their detection, which results in false positives. Hence, sometimes, the samples must undergo treatment in specialised laboratories that increases the time and cost of analysis.
The challenge tackled by UA researchers was to develop materials of high affinity with the molecule to be detected to avoid these false positives. To this end, the Group of Electrocatalysis and Polymer Electrochemistry creates electrodes using two basic strategies. The first is the development of third-generation biosensors that could be applied in glucose control in diabetics.
"We have immobilised a model protein using silica layers by sol-gel techniques. The silica (silicon oxide) is a common and cheap material —in fact, it is the main component of beach sand. By modulating the composition of these layers, a direct electrochemical reaction between the protein and the electrode occurs. Thanks to this innovation, we introduce other proteins, including glucose oxidase, and develop different substances control devices, explains one of the researchers of the Group, Francisco Montilla.
In another line, they are working in biomimetic sensors, that is, functioning as biosensors but they do not contain biomolecules such as the proteins necessary in the usual electrochemical sensors. "Although we found that biosensors have very interesting properties, they still have effiency problems, they are relatively expensive and, above all, sometimes you cannot find in the nature a protein that metabolises the particular molecule that we need to detect", Montilla said. "Therefore, in our laboratory, we are modifying electrodes with silica layers with special properties that act as a selective filter that we can produce ad hoc to a certain molecule", he adds.
In particular, this line of work has been developed thanks to funding from the Ramon Areces Foundationthat has finalised this year. Also, the research group is developing a project of the Ministry of Economy and Competitiveness within their call for Excellence and a Prometheus Project by the Valencian Government with which some of this research work is financed.
One of the tests performed by the Group for the development of biosensors. Specifically, electrochemical deposition of a sensor silica layer
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