Chemists from three leading higher education institutions of St. Petersburg have developed a method of diagnosing  kidney diseases with the help of juice boxes, a piece of a CD and a smartphone.

This was reported by the press service of the St. Petersburg State University. “The method makes it possible to define quickly and accurately the content of creatinine (the final product of a proteinaceous exchange in muscular tissue) in real biological liquids, whereas its accumulation is an indicator of kidney pathology. According to scientists, their development can be of great use to physicians working in remote places of the planet, where it is not always possible to make analyses necessary for diagnosis”, - the press service specified.

Normally creatinine is completely removed from an organism, but in case of particular kidney pathologies it starts accumulating. Therefore the indicators of creatinine level in urine or blood are an important clinical biomarker used for assessment of muscular metabolism and diagnosis of various kidney diseases.

Improvised Diagnostics 

Juice box carries out the function of lightproof case, a CD piece serves as a diffraction lattice, and a smartphone is needed to photography the received range. Picric acid is also necessary as a reagent and it is available in drugstores. Scientists explain that the work principle of the device is quite simple: a sample of urine or blood is poured into a container with transparent walls and picric acid is added there, thus making brightly-coloured complexes with creatinine. A narrow slit is cut in the box, and a piece of CD and a smartphone is placed inside. Then the sample is put against the slit and highlighted with an ordinary bulb. The light, passing through the sample and reflected from the CD creates a rainbow effect on the box walls. This image is photographed with the phone and processed on an ordinary computer.

Scientists have established that there is a direct dependence of range strips on the intensity of the sample’s coloring with picric acid, which is directly connected to concentration of creatinine. The whole operation, including the production of the device, takes several hours. The device is quite exact - relative errors make less than 10 percent. It is quite enough for getting primary diagnostics and assessing the scale of the problem.

The chief performer of the project Bruno Debeu, a postdoctoral research fellow of the St. Petersburg State University and a graduate of the Lille University (France) works in the chemical sensor laboratory of the St.Petersburg State University under the leadership of Andrey Legin and Dmitry Kirsanov. The work is carried out jointly with scientists from the St. Petersburg Polytechnical University and the National Research University of Information Technologies, Mechanics and Optics.