Wood “diagnosis” of diseases of saliva.

By | May 9, 2023

He is one of the doctors’ permanent “helpers” when they want to check their patients’ throats. The reason for the tongue depressor, this wooden spatula that does exactly what its name says: press the tongue so that the specialist can have a better… view of the inside of the examinee’s mouth. Since this exam, although simple, is not the most “beloved” of young and old, today we have for you: it is actually not us, but researchers from the Laboratory of Analytical Chemistry of the Department of Chemistry of the National and Kapodistrian University. of Athens (EKPA) – an advanced tongue depressor of the future, which you won’t even need to put in your mouth, but when it comes in contact with some saliva, you will be able to diagnose different diseases in an easy and non-invasive and highly cheap!

The “intelligent” tongue depressor that was recently presented (online publication April 20) in the scientific journal “Analytical Chemistry” is the “child” of the collaboration of two groups from the EKPA Department of Chemistry – that of the associate professor Christos Kokkinos who was also the lead author of the relevant study as well as that of Prof. Anastasios Oikonomou (PhD students also participated Eleni Koukovitis and Dionysus Soulis).

For diabetes and periodontitis

As Mr. Kokkinos explains to BIMA-Science, the two groups have been working for years on the development of sensors that in the future can be used in clinics or even at home. “The trend now is to develop sensors without the need for special and very expensive instruments to manufacture. A typical example is the tongue depressor sensor that controls glucose levels related to diabetes, but also nitrites related to periodontitis and other gum diseases.”

A world first for the Greek team

The Greek researchers’ tongue twister is even linked to a world first: it is the first time, in terms of sensor creation, that a low-power diode laser has been used to graphite wood; Through graphitization, the wood becomes an electrode. “Our logic was to take a disposable tool and give it more functions so that it can become a biosensor” points out Mr. Economou and explains that nowadays the graphitization (commonly known as burning) of wood to create sensors involves a high-powered carbon dioxide laser that is very expensive, while very special conditions are required to make it cash. “It is essential that there is no oxygen so that the wood does not catch fire, which must also be covered with special flame retardants. Our study showed that the process can be done with a very low-cost laser engraver, which is sold commercially as a toy for home use.”

Future diagnosis of many diseases.

Two measurement zones have been engraved on the tongue depressor with the diode laser, which are separated from each other by a line drawn with a special marker: glucose measurement is carried out in one zone and glucose measurement is carried out in the other. nitrites. The user puts a saliva sample in each area to obtain the corresponding measurement. “In the future, more areas could be recorded in the tongue depressor that allow the simultaneous detection of different biomarkers” says Mr. Kokkinos, adding that another biomarker that could be “etched” into tongue pressure would be chlorides, the existence of which is linked to cystic fibrosis, or uric acid linked to gout, metabolic syndrome, diabetes and oral cancer.

After taking the sample, the biomarkers are measured with a potentiostat, an instrument that measures the current due to redox reactions of the biomarkers on the graphited wood electrodes. So far, the Greek scientists’ simple-to-develop and easy-to-use wood sensor has been tested on synthetic saliva samples and showed satisfactory sensitivity in detecting glucose and nitrite levels.

From theory to the hands of doctors

When could such a tool reach the hands of doctors? is a reasonable question that we asked the EKPA scientists. As they responded, “We are focusing on the development of sensor models, however, bringing such a sensor into clinical practice requires many steps, such as clinical trials by scientists from other fields and optimization of various assay parameters. Thus that we are giving a research idea and we hope that one day it will become flesh and blood”…

‘Finger’ drink control and ‘ring’ glucose detection

The EKPA Analytical Chemistry Laboratory team has developed other economical and easy-to-use sensors. One of those sensors that was presented in 2022 in the scientific journal “Analytical Chemistry” is a portable electronic finger, which detects the possible presence of violative substances and painkillers in drinks.

As Mr. Kokkinos explains, it is a “Do-it-yourself” electrochemical finger (e-finger) resulting from 3D printing, which allows the user to quickly and immediately self-diagnose the existence of psychotropic substances (flunitrazepam, scopolamine, ketamine ) used as “rape pills”, but also the pain reliever paracetamol (used in low-quality drinks – “bombs” – to reduce the hangover the next day so that its adulteration is not easily detected) by dipping it into a shot of alcohol.

“The e-finger can be printed at home in any size with an inexpensive home 3D printer. It connects to a miniature potentiometer installed in a “smart” mobile phone and allows direct control of the quality and safety of alcoholic beverages.

In 2021 with their publication again in “Analytical Chemistry” the two groups also presented an electrochemistry “ring” (e-ring), which measures blood glucose in sweat and offers non-invasive monitoring of diabetes. And the electronic ring, consisting of three carbon-based plastic electrodes, is 3D printed and connected to a small potentiometer controlled by a smartphone. Sensors of the future… for the future made in Greece!

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