Laboratory on paper

Testing for malaria or cancer at home is becoming a reality

Daria Zagorskaya, Vesti

Malaria is one of the main health problems in Africa, Southeast Asia and some other regions. In 2015 alone, about 214 million cases of the disease were recorded worldwide. 438 thousand sick people died and mostly these are children of Africa.

Associate Professor of Ohio University Abraham Badu-Tawiah, knowing about this situation, decided to find an easy way to diagnose malaria and other diseases at all costs. Such a solution is necessary for remote settlements, from which it takes weeks to get to the nearest hospital.

The main idea is that people can put a drop of blood on paper and send it to the laboratory for diagnosis, and contact a doctor only if any disease is detected.

The already patented technology is described in an article in the Journal of the American Chemical Society (Chen et al., Mass Spectrometry for Paper-Based Immunoassays: Towards On-Demand Diagnosis), resembles the actively developing "laboratory on a chip" technique. But instead of plastic, in this case, the most ordinary paper is used, glued together with double-sided tape and passed through a conventional inkjet printer. That's just the ink in the printer is not ordinary, but wax.

As a result, after printing on paper, channels and reservoirs with waterproof contours are formed, which allow you to capture and hold a drop of blood between the layers. Dozens of individual tests can fit on a regular A4 sheet, a little larger than a postage stamp. It remains simply to cut them and use them for their intended purpose.

"In order to be tested, it is enough for a person to leave a drop of blood on a strip of paper, fold it in half, put it in an envelope and send it by mail," Badu–Tavia says in a press release from the university Testing for malaria-or cancer-at home, via cheap paper strips.

Note that the principle of operation of the new tests differs from the already familiar tests for blood sugar and pregnancy, which use enzymes or gold nanoparticles to change the color of the carrier. Instead, small synthetic chemical probes carrying a positive charge are placed on the new paper strips. It is these ultra-sensitive "ion probes" that make it possible to test test strips using a portable mass spectrometer.

Each ion probe captures a specific biomarker of the disease from the blood. When this happens, all the compounds obtained during the past chemical reaction remain unchanged for at least 30 days (which is more than enough for a trip to a remote laboratory).

The system remains stable under the influence of standard environmental conditions – light, temperature, humidity (even in the African climate). Modern enzymatic tests did not even dream of this, the developers of the novelty note. They are extremely capricious and require strict storage conditions.

The first tests showed the possibility of effective detection of the biomarker of the most common pathogen of malaria – malaria plasmodium (Plasmodium falciparum). In addition, with the help of the new test, cancer biomarkers were successfully detected – antigen 125, indicating ovarian cancer, and carcinoembryonic antigen, indicating colon cancer.

The reliability of the new diagnostic system opens up a new world of medical care not only in third world countries, but also in any other. Going to the doctor often requires not only time, but also serious financial costs, for example, in the USA. In particular, people with cancer in remission should take tests to monitor their condition at least once a month. If they can independently conduct tests and send them to the laboratory by mail, the control can be carried out much more often.

The cost of one test strip in Ohio can be as little as 50 cents, and mass production will only make it cheaper. Laboratories will have to bear the biggest costs. A portable mass spectrometer currently costs about 100 thousand US dollars (almost 6.5 million rubles at the current exchange rate). However, now there is an active development of a cheaper and more compact model that can be installed anywhere.

Nevertheless, such costs are fully justified and are a potential boon for the African economy, where malaria annually takes $12 billion from the budgets of countries due to the loss of the working capacity of the population.

Now Ohio University is planning to license a new technology for medical diagnostics. The developers hope that clinical trials will take place in the next three years. In addition, the researchers are working to expand the list of identified diseases and plan to make their tests non-invasive, that is, so that there is enough saliva or urine for their use.

Portal "Eternal youth" http://vechnayamolodost.ru  01.07.2016