ИСТИНА

The abundance of smartphones around the world provides the possibility of creating a cheap and easy to use point-of-care (POC) testing systems. POC tests are used to perform various assays in situ for a reasonable price. A lot of these systems have been developed and are used for analytical purposes in different fields of research and in everyday life. They include mobile applications for health assessment, smartphone-based microscopy, electrochemical sensing and diverse colorimetric assays. Nowadays rapid diagnostics for monitoring diseases, contamination of food and environment are usually performed using ELISA because of its commercial availability and simplicity. However expensive and bulky equipment is required. To solve this problem cameras, digital color analyzers, scanners and custom portable readers were applied and they demonstrated promising results. Nevertheless, these detectors are still expensive and require additional equipment. In this study we evaluated the efficiency of color codes reading using smartphones to quantify color and color intensity change. We developed a system for measuring pH level using pH strips. Color codes of the strips moistened with pH buffers were compared and analyzed using a mobile app “RGB”. Six smartphones were applied to compare their detection abilities. Calibration curves generated from the different gadgets varied insignificantly and allowed us to determine the pH level using any phone with 10 % error. This provides an opportunity to develop a mobile app for accurate pH detection. Furthermore, we developed a method for detecting colorimetric and falsely-plasmonic ELISA in 96-well microplate using a smartphone. This detection approach greatly simplifies the reading of ELISA, making it cheaper to use. For this different color codes to detect tetramethylbenzidine and gold nanoparticles were studied; optimal color code was used to make a calibration curve. The results of predicted samples acquired with calibration curves matched the real means within 15 %.